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TT24-7 User Manual

1. If the split function is configured configuration e3 this rear valve has four points of connection i e to the T piece connecting the two front valves to the tube desorption line to the split effluent line and finally to a transfer line leading to the capillary column See section 2 5 for an overview flow schematic of this 3 heated valve configuration Figure 8 shows the schematic of this rear valve QUI 1016 V2 2 Aug 06 22 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Figure 8 Schematic of third rear valve Figure 9 shows the relative position of these three valves valve within the TT24 7 It also shows the location of the heated transfer line connection port into the TT24 7 the twin trap box assembly the pneumatics module and the tube desorption assembly Rear heated valve Front heated valves Trap box assembly Pneumatics module pnly on e2 e3 onfigurations Tube desorption assembly Figure 9 Position of the principle system components of the TT24 7 2 4 2 Pneumatics module The pneumatics module is a single sub assembly located at the front of the TT24 7 as seen in Figure 9 It is locked in position by a single M4 retaining screw Removal of a trap from its location in the valve box requires the pneumatics assembly to be removed See section 3 4 for complete details of how to remove replace the traps The modu
2. PC to GC Communications cable eg LAN RS232 Agilent UTD 5098 Remote Start Cable P N Thermo UTD 5108 Figure 69 Direct serial connection Figure 70 shows a similar schematic but in this case USB communication is used QUI 1016 V2 2 Aug 06 95 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International USB Hub USB to Serial cables P N U USBSR Standard USB Cable Serial Cables Remote Start P N 2 0189 PC to GC Communications cable eg LAN Agilent UTD 5038 Remote Start Cable P N Thermo UTD 5108 Figure 70 USB connection It is possible to have a combined configuration in which one of the serial communication cables is connected directly to the PC from the TT24 7 and the other connects via USB 3 1 4 Power recycle box Remote system control of the TT24 7 and associated GC or GCMS can be very useful Where access to the system is difficult e g remote location high security worker exposure safety etc the ability to run and monitor the respective instruments remotely is very advantageous This is particularly evident where the continuous sampling mode is being used Remote PC to PC control is achieved using commercially available software packages an example of this is VPN A specific use of this is in the case of power failure Power failures will close down both the TT24 7 and the GC system however the con
3. 11 Spherocarb UniCarb 60 80 mesh only 12 Carbosieve SIII 60 80 mesh only 13 Carboxen 1000 range of mesh sizes 14 Molecular Sieve 5A 15 Molecular Sieve 13X Retention Volumes and Safe Sampling Volumes Table of Contents Figures TT24 7el1 basic system configured only for continuous sampling TT24 7e2 standard system configured with the following additional features TT24 7e3 Figure 1 TT24 7 User Interface showing both sampling modes Figure 2 Sample gas inlet on TT24 7 Figure 3 Schematic representation of TT24 7 sequence in continuous operation Figure 4 TT24 7e2 showing tube accessory fitted and sorbent tube ready to be sealed into position Figure 5 TT24 7e2 showing tube accessory fitted and sorbent tube sealed into flow path Figure 6 TT24 7e3 showing the tube desorb and split accessories fitted Figure 7 Schematic showing the two TT24 7 trap valves Figure 8 Schematic of third rear valve Figure 9 Position of the principle system components of the TT24 7 Figure 10 Position of Trap A and Trap B within the trap housing Figure 11 TT24 7 cold trap note the restricted inlet outlet end and the quartz collar on the unrestricted end Figure 12 Transfer line connection between TT24 7 and GC system QUI 1016 V2 2 Aug 06 7 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com 129 130 130 130 131 131 132 132 133 133 134 134 135
4. Desorption Tube MFC amp Pump Sample in Trap B KEY Flowof Carrier Gas Carrier Gas no flow a Flowof Sarple Gas Sarrple Gas no flow Figure 24 TT24 7e2 Continuous sampling trap A desorbing trap B sampling Trap A now fires If this is the first run for A this run is treated as a clean up run however if this is a subsequent run then real sample will be transferred across to the capillary column for analysis To see how the time overlap of sampling dry purging trap fire and cooling occurs relative to the GC oven cycle time please refer to section 2 3 1 QUI 1016 V2 2 Aug 06 41 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 2 Tube desorb mode TT24 7e2 2 5 2 2 1 Standby Desorption Tube MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no flaw gt Flow of Sample Gas Sample Gas no flow Figure 25 TT24 7e2 Tube desorb mode standby In this non sampling mode carrier gas alone is continuously supplied to the capillary column No other gas flow occurs within the TT24 7 unit during this time QUI 1016 V2 2 Aug 06 42 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 2 2 Leak testing tube MFC amp Pump Sample in KEY Flo
5. Sorbent Strength Medium Strong Specific Surface Area m2 g 560 Approximate analyte volatility range n C3 4 to n Cg Boiling point 50 C to 150 C Example Analytes Light hydrocarbons Sorbent Maximum Temperature gt 400 C 350 C to 400 C 350 C to 400 C Notes Hydrophobic Recommended Conditioning Temperature Recommended Desorption Temperature Low artefacts lt 0 1 ng Some activity with labile compounds Friable 6 Chromosorb 102 range of mesh sizes available Sorbent Strength Medium Specific Surface Area m2 g 350 Boiling point 50 C to 200 C Alcohols oxygenated compounds haloforms less volatile than methylene chloride Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature 250 C Recommended Conditioning Temperature 225 C to 250 C Recommended Desorption Temperature No higher than 220 C Notes High artefacts 10 ng Hydrophobic Inert suitable for labile compounds For trace level analysis condition at 225 C amp desorb sample tubes no higher than 200 C to reduce background 7 Porapak Q range of mesh sizes available Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range QUI 1016 V2 2 Aug 06 Markes International Ltd T 44 0 1443 230935 Medium 550 n Cs to n C12 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Boiling point 50 C to 200 C VOC s within volat
6. TT24 7 Near Real Time Monitoring Operators Manual AuGcust 2006 QUI 1016 VERSION 2 2 MARKES ational Ltd 4 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International This page left intentionally blank QUI 1016 V2 2 Aug 06 1 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International TT24 7 User Manual Table of Contents Introduction 1 0 Quickstart Guide using the TT24 7 1 1 Running the TT24 7 system 1 1 1 Using an existing TT24 7 method 1 1 2 Creating a new TT24 7 method 2 0 The TT24 7 Thermal desorption System 2 1 An introduction to the TT24 7 system 2 2 TT24 7 Hardware configurations 2 3 Sampling modes 2 3 1 Continuous sampling 2 3 2 Single tube desorption 2 3 3 Split sampling 2 4 Principle system components 2 4 1 Valving assembly 2 4 2 Pneumatics module 2 4 3 Peltier cooled traps A and B 2 4 4 Heated transfer line 2 4 5 Tube desorption and sample split pneumatics 2 4 6 Electronic pneumatic control EPC 2 4 6 1 Carrier gas connections 2 4 6 2 Connection to Agilent Technologies 6890GC 6850 GC 2 4 6 3 Connection to Thermo Electron Trace FOCUS GC 2 4 6 4 Connection to other GC systems QUI 1016 V2 2 Aug 06 1 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com 11 13 13 13 14 15 15 16 16 16 18
7. 07 500 ml mi TrapB State 0 4 0 0 25 0 C Sample Gas Air Sample Time 0 0 min Transfer Line 0 0 120 0 C Carrier Gas He Dual Front HY 0 0 120 0 C Figure 50 Instrument status bar TT24 7e1 QUI 1016 V2 2 Aug 06 68 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International The instrument status bar figure 50 is located at the bottom of the top level screen It is divided into four sections i e Instrument Status Heated zones GC and Flow Controller 2 9 1 3 1 Instrument status This shows the status of the continuous sampling run which is operating Instrument status Indicates the current status of traps Aand B Examples of status messages are Sampling Purging Desorbing Waiting for GC Ready Equilibrating Sample Time How long the current trap has been sampling for see section 2 9 1 1 5 2 9 1 3 2 Heated zones This section shows the heated zones monitored within the TT24 7 Trap A Trap B Transfer Line Dual front HV The status bar shows two adjacent numbers The first represents the actual value and the second the set point value If these two numbers are equal they appear in black font if however the actual value is not at the set point it will appear blue If the TT24 7 is started when any one of these values is blue then the software will enter an equilibrating mode and the run will only commence when the value becomes ready
8. 21 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 4 3 Peltier cooled cold traps A and B 2 4 4 Heated sample transfer line 2 4 5 Optional tube desorption and or sample split pneumatics 2 4 1 Valving assembly The valving assembly within the TT24 7 consists of up to three heated valves Each valve is manufactured from a solid block of PTFE and machined to provide the required flow paths for sampling and desorption of a sample gas stream For hardware configuration e1 which only offers the continuous sampling configuration two valves are required one for each trap Each valve has three points of connection i e where the trap locates into the valve where sample gas enters the valve and where the desorbed analytes leave the valve Figure 7 is a schematic which shows these connections and the two opposing pins at the top and bottom of the valve which control the active flow path within the valve i e sampling dry purging backflush desorption etc These pins are either up or down and are actuated by an external gas supply mo Two trap valves HVA amp HVB Figure 7 Schematic showing the two TT24 7 trap valves When the additional configurations of tube desorption and split sampling are built into the TT24 7 configurations e2 e3 then a third heated valve is required which connects via a T connection to the two valves described above
9. He 7 Sample Gas air 7 Cancel Figure 52 Options dialogue box gas tab This section defines the pressure units and the sample and carrier gas selection Pressure units The pressure unit selection is either psi or kPa Note 1 psi 101 325 kPa However note that there are no displays of pressure on the instrument status bar on a TT24 7e1 system Carrier gas type Choices of Helium He Nitrogen N2 Hydrogen H2 and diagnostic air are available Sample gas type Choices of Air N2 He Hz safety considerations may apply using this gas and Carbon Dioxide CO gt are available This selection configures the flow calibration of the mass flow controller QUI 1016 V2 2 Aug 06 72 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 1 5 2 Ports Gas Ports System E Mail Communications Port Analyser Port COMI MFC Port coms Baud Rate 57600 Baud Rate 57600 r GC Interface Logic f Open Start f Open Ready GCStart out GC Ready fin i Closed Start Closed Ready Figure 53 Options dialogue box ports tab This screen consists of two sections the communications port and the GC interface logic These two sections control communication between the TT24 7 and the associated PC system and the ready not ready and start signal logic betw
10. These values have to be equal 2 C tolerance value for the system to become ready The transfer line and heated valves are controlled collectively by the flow path temperature see section 2 9 1 1 3 2 9 1 3 3 GC The cable connecting the TT24 7 to the associated GC see section 3 1 performs two functions Firstly it monitors the GC ready status as specified in the GC interface logic of the TT24 7 software see section 2 9 1 5 2 If the GC set point values are correct and equilibrated and the software for the GC is in a state to accept a start signal from the TT24 7 then the GC will be ready This ready status is relayed to the TT24 7 and observed in the GC status box If the GC is not ready then a Not Ready comment appears When the GC is ready the second function for the cable is to send the start signal from the TT24 7 to the GC at the point of trap fire so it can begin its analytical process If the GC is not ready at the end of the sampling time then extended or fixed time sampling commences see section 2 9 1 5 3 QUI 1016 V2 2 Aug 06 69 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 1 3 4 Flow controller This component of the status box is not shown by default and requires configuring within the TT24 7 software see section 2 9 1 5 3 When configured following information is given Flow rate the sampling flow rate
11. Where fine mesh size material is used i e 80 100 mesh or finer the maximum flow rate will be reduced Ultimately the fastest flow rate achievable is determined by specifying the maximum flow rate of 1 L min and observing the actual flow value on the status bar see section 2 9 1 3 at the bottom right side of the user interface In certain applications where the analyte concentration is very low i e sub ppb and there is a time restriction on sampling i e NRT there is a temptation to set a very fast sampling flow rate to maximise the amount of analyte passing into the trap in unit time For example sampling at 1 L min for 10 minutes results in a sampling volume of 10L If the analyte concentration is very low e g in the pg L concentration i e ppt then a 10L volume would contain sufficient sample in theory for detection by selective GC detectors or by GCMS However sensitivity is very dependant on the signal to noise S N ratio of the resultant chromatographic peak If this is sharp i e peak widths lt 5 seconds then much better integration and detection is possible than for peak widths gt 15 seconds In practice it has been shown that very fast sampling flow rates gt 800 mL min with certain sorbent materials produces poor or broad peak shapes and this can compromise the minimum detection limit MDL for that compound If the same compound is run at a lower flow i e 400 mL min as opposed to 800 mL min this can result in a m
12. because the flow controller was unable to pull the required flow rate over the sampling time due to a failing cold trap or other problem A warning message does not affect the operation of the TT24 7 system but gives information about something which may affect the quantitation and the results 2 9 2 7 3 Error messages ERROR Trap A not heating ERROR Valve not heating ERROR Line not heating ERROR Trap A over temperature ERROR Valve over temperature ERROR Line over temperature If one of the above errors occur then the TT24 7 system will shut down and await operator service engineer intervention 3 0 User Installed Components and Maintenance 3 1 System cabling TT24 7 PC GC This section describes the cabling connections required to correctly operate and control the TT24 7 system The TT24 7 has electrical connections with both the associated GC and the controlling PC A power supply is also required 100 240V There are four cables attached to the back of the TT24 7 system These consist of i and ii Two 9 pin D serial RS232 communication cables P N Z 0189 iii A single 25 pin remote GC start stop cable which is instrument specific Agilent GC P N UTD 5098 Thermo Electron GC P N UTD 5108 any other GC system uses UTD 5095 iv A power cable P N Z 0024 These four cables must be connected correctly for successful operation of the TT24 7 system and remote starting of the associated GC QUI 1
13. described in section 1 1 above The user interface for both sampling modes is shown below and varies slightly depending on the selection made Figure 1 Method default mth modified Method default mth modified Mode 14m n A4 free hie TrapB Flow Path Temp C Purge Flow Path Temp C Prepurge Time Prepurge Time 1 0 min H and TL 120 0 1 0 min H and TL 120 0 es TT Sampling Sample Flow Rate Trap Low Temp Desorb Flow Trap Low Temp 500 0 ml min 25 0 ie 500 0 ml min 25 0 e Sample Time Trap High Temp Desorb Time Trap High Temp 10 0 min 100 0 C 3 0 a 100 0 c Trap Hold Time Desorb Temp Trap Hold Time 10 0 min 250 0 C 10 0 fame Split u Enable Trap Split Save Figure 1 TT24 7 User Interface showing both sampling modes Step 2 Enter set point values After selecting the sampling mode the desired set point values for each field need to be specified so that the correct temperatures and flows are used for the sampling and desorption phases The Quickstart guide supplied with the TT24 7 ITSO15 has a description of these fields on the reverse side see section 2 9 for further details Note the split functionality shown in the user interface above is only present if the split option is configured within the TT24 7 Product Number TT24 7e3 QUI 1016 V2 2 Aug 06 14 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E
14. enquiries markes com TT24 7 User Manual Markes International Without this the system samples in a splitless mode directly into the capillary column for maximum sensitivity Step 3 Save the method After all the set points are specified click the Save button shown on the interface above This allows the operator to specify the correct method file name ending in a mth suffix To operate the TT24 7 simply follow the stepwise process described above in section 1 1 1 2 0 The TT24 7 Thermal desorption System This section covers the design philosophy of the TT24 7 the sampling protocols available and the hardware options that can be configured to achieve these different sampling techniques 2 1 An introduction to the TT24 7 system Thermal desorption as an analytical technique can be broadly divided into two sampling categories namely off line or on line Off line sampling incorporates both tube based pumped or diffusive and canister bag grab samples whereas for on line analysis the sample is a flowing gas stream passing directly into the focusing trap for enrichment Tube based sampling has the benefit of two stage pre concentration i e from the primary tube into the cold trap of the thermal desorption system e g UNITY and then from the cold trap into the capillary column These two phases can typically enrich the sample by a factor of 106 However for on line analysis a much faster analysis time is required so
15. 11 12 12 12 14 17 18 19 19 21 22 23 23 24 25 26 TT24 7 User Manual Markes International Figure 13 Carrier gas supply connections on the back panel of the TT24 7 29 Figure 14 TT24 7 flow schematic e3 configuration showing the additional gas lines associated with the GC EPC module Figure 15 TT24 7e1 Standby Figure 16 TT24 7e1 Trap A sampling trap B purging Figure 17 TT24 7e1 Trap A sampling trap B desorbing Figure 18 TT24 7e1 Trap A purging trap B sampling Figure 19 TT24 7e1 Trap A desorbing trap B sampling Figure 20 TT24 7e2 Continuous sampling standby Figure 21 TT24 7e2 Continuous sampling trap A sampling trap B purging Figure 22 TT24 7e2 Continuous sampling trap A sampling trap B desorbing Figure 23 TT24 7e2 Continuous sampling trap A purging trap B sampling Figure 24 TT24 7e2 Continuous sampling trap A desorbing trap B sampling Figure 25 TT24 7e2 Tube desorb mode standby Figure 26 TT24 7e2 Tube desorb mode leak testing tube Figure 27 TT24 7e2 Tube Desorb Mode Leak testing trap A Figure 28 TT24 7e2 Tube desorb mode tube purge Figure 29 TT24 7e2 Tube desorb mode tube desorption Figure 30 TT24 7e2 Tube desorb mode trap A purge Figure 31 TT24 7e2 Tube desorb mode trap desorption Figure 32 TT24 7e3 Continuous sampling standby Figure 33 TT24 7e3 Continuous sampling trap A sampling trap B dry purging
16. 20 21 22 23 24 25 27 27 28 30 31 31 TT24 7 User Manual 2 5 TT24 7 flow schematics 2 5 1 TT24 7e1 hardware configuration 2 5 1 1 Standby 2 5 1 2 Trap A sampling trap B purging 2 5 1 3 Trap A sampling trap B desorbing 2 5 1 4 Trap A purging trap B sampling 2 5 1 5 Trap A desorbing trap B sampling 2 5 2 TT24 7e2 hardware configuration 2 5 2 1 Continuous sampling mode TT24 7e2 2 5 2 1 1 Standby 2 5 2 1 2 Trap A sampling trap B purging 2 5 2 1 3 Trap A sampling trap B desorbing 2 5 2 1 4 Trap A purging trap B sampling 2 5 2 1 5 Trap A desorbing trap B sampling 2 5 2 2 Tube desorb mode TT24 7e2 2 5 2 2 1 Standby 2 5 2 2 2 Leak testing tube 2 5 2 2 3 Leak testing trap A 2 5 2 2 4 Tube purge 2 5 2 2 5 Tube desorption 2 5 2 2 6 Trap A purge 2 5 2 2 7 Trap A desorption 2 5 3 TT24 7e3 hardware configuration 2 5 3 1 Continuous sampling mode TT24 7e3 2 5 3 1 1 Standby 2 5 3 1 2 Trap A sampling trap B dry purging 2 5 3 1 3 Trap A sampling trap B desorbing 2 5 3 1 4 Trap A purging trap B sampling 2 5 3 1 5 Trap A desorbing trap B sampling 2 5 3 2 Tube desorb mode TT24 7e3 2 5 3 2 1 Standby 2 5 3 2 2 Leak testing tube QUI 1016 V2 2 Aug 06 2 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 Markes International E enquiries markes com 31 32 32 33 34 35 36 37 37 37 38 39 40 41 42 42 43 44 45 46 47 48 49 49 49 50 51 52 53 54
17. 3 butadiene 350 C 400 C 300 C 350 C max increase temperature gradually from 100 C To suit analyte Significantly hydrophilic do not use in humid conditions High artefacts gt 10 ng Easily amp irreversibly contaminated by higher boiling components F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Retention Volumes and Safe Sampling Volumes The most accurate method of ensuring a particular sorbent tube will quantitatively retain a particular analyte is to determine its retention volume for that analyte Retention volumes are usually quoted in litres per gram of sorbent and must be extrapolated to determine the retention volume on the mass of sorbent in a standard tube They are always quoted at a set temperature usually 20 C A comprehensive list of retention volumes for different analytes on several sorbents packed into industry standard 3 5 x 1 4 OD tubes is given in MDHS 72 Volatile Organic Compounds in Air The MDHS Methods for the Determination of Hazardous Substances series comprises validated methods produced by the United Kingdom Health and Safety Executive for occupational hygiene work Copies of these publications may be ordered from The Stationary Office Holburn Book Shop 59 60 Holburn Viaduct London EC1A 2FD UK It is possible to measure retention volumes in the laboratory by the following procedure using a gas chromatograph configured with a
18. 54 55 TT24 7 User Manual 2 5 3 2 3 Leak testing trap A 2 5 3 2 4 Tube purge 2 5 3 2 5 Tube desorption 2 5 3 2 6 Trap A purge 2 5 3 2 7 Trap A desorption 2 6 Software control and configuration 2 7 Software installation 2 8 Firmware download 2 9 Software control top level 2 9 1 User interface for TT24 7el1 hardware configurations 2 9 1 1 Method parameters 2 9 1 1 1 Mode 2 9 1 1 2 Prepurge time 2 9 1 1 3 Flow path temp 2 9 1 1 4 Sample flow rate 2 9 1 1 5 Sample time 2 9 1 1 6 Trap low temperature 2 9 1 1 7 Trap high temperature 2 9 1 1 8 Trap hold time 2 9 1 1 9 Save 2 9 1 2 Flow display 2 9 1 3 Instrument status bar 2 9 1 3 1 Instrument status 2 9 1 3 2 Heated zones 2 9 1 3 3 GC 2 9 1 3 4 Flow controller 2 9 1 4 Software icons and menu items 2 9 1 4 1 Software icons 2 9 1 4 2 Menu bar 2 9 1 5 Options 2 9 1 5 1 Gas QUI 1016 V2 2 Aug 06 3 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E Markes International 56 57 58 59 60 61 62 62 64 65 65 65 65 65 66 66 67 67 68 68 68 68 69 69 69 70 70 70 71 72 72 enquiries markes com TT24 7 User Manual 2 9 1 2 9 1 2 9 1 5 2 Ports 5 3 System 5 4 eMail 2 9 1 6 User diagnostics 2 9 1 7 Reporting module 2 9 1 7 1 Information messages 2 9 1 7 2 Warning messages 2 9 1 7 3 Error messages 2 9 2 User interface for TT24 7e2 and TT24 7e3 hardware configurations 2 9
19. 9 2 7 Reporting module 2 9 2 7 1 Information messages 2 9 2 7 2 Warning messages 2 9 2 7 3 Error messages 3 0 User Installed Components and Maintenance 3 1 System cabling TT24 7 PC GC 3 1 1 TT24 7 power cable ON OFF switch 3 1 2 Communications and Remote start cabling 3 1 3 Serial and or USB Cable connections 3 1 4 Power recycle box 3 2 Gas requirements 3 2 1 User maintenance for gas requirements 3 3 Installation and removal of heated transfer line 3 3 1 Connecting the transfer line to the gas chromatograph 3 3 2 Installing the fused silica transfer line insert 3 3 3 Connecting the transfer line to the TT24 7 3 3 3 1 e1 systems 3 3 3 2 e2 e3 systems 3 3 4 Coupling the fused silica transfer line to the GC column 3 3 5 User maintenance of transfer line 3 4 Installation and removal of Cold Traps 3 4 1 Installing cold traps 3 4 2 Removing the cold traps QUI 1016 V2 2 Aug 06 5 87 88 89 90 91 91 92 92 92 92 93 93 95 96 97 98 98 98 100 101 101 105 107 107 108 108 109 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 4 3 Available Cold Traps 3 4 4 User maintenance of TT24 7 cold traps 3 4 4 1 Packing cold traps 3 4 4 2 Cold trap lifetime 3 5 Installation removal of sampling tube e2 e3 3 6 Installation removal of split tube e3 4 0 Troubleshooting 4 1 Leak testing the
20. A firing eventually and the GC oven After trap A fires both traps will be conditioned and the GC column cleaned of any residual material It is important to note that the GC cycle time must be less than the TT24 7 sampling time or this will add to the overall cycle time of the method If the GC cycle time increases during the continuous sampling mode e g because the oven cool down time increases then the system will go into an extended sampling mode for the trap which is currently sampling This continues until the GC does eventually become ready at which point the trap fires and the sequence continues See section 2 5 for further information on the TT24 7 flow schematics Additionally the sampling time must be greater than the sum of purge trap fire and trap cooling times typically 2 minutes 2 3 2 Single tube desorption Available with hardware configurations e2 and e3 The TT24 7 may be configured with the capacity to desorb a single tube For this type of analysis Tube Mode must be selected as the sampling mode in the TT24 7 software figure 1 QUI 1016 V2 2 Aug 06 18 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International The tube to be analysed is inserted into a dedicated tube oven located on the left hand side of the front facing instrument The tube is retained and sealed by two o rings P N U COV10 one at either end of the oven ho
21. By starting the TT24 7 software the continuous sampling process commences The sample passes initially onto trap A The date and time that the sampling started and the trap that is being sampled are reported as an information message in the reporting module of the software see section 2 9 2 7 e g 05 12 2005 10 49 31 INFO Sampling Started on Trap A At the same time trap B dry purges with carrier gas in the sampling direction This removes air and moisture from the trap prior to firing The dry purge flow rate through the trap B at this time is controlled by a needle valve connected to SV6 The sample gas flow rate passing into the TT24 7 is controlled by the internal mass flow controller MFC QUI 1016 V2 2 Aug 06 38 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 1 3 Trap A sampling trap B desorbing Desorption Tube MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no flaw a Flow of Sample Gas Sample Gas no flow Figure 22 TT24 7e2 Continuous sampling trap A sampling trap B desorbing The first two runs of the continuous sampling mode i e trap A and trap B would typically not be used for quantitative analysis of the sampled air but as a clean up process for both traps After both traps have been fired once then the subsequent samples may be quantified Afte
22. Figure 34 TT24 7e3 Continuous sampling trap A sampling trap B desorbing Figure 35 TT24 7e3 Continuous sampling trap A dry purging trap B sampling Figure 36 TT24 7e3 Continuous sampling trap A desorbing trap B sampling Figure 37 TT24 7e3 Tube desorb mode standby Figure 38 TT24 7e3 Tube desorb mode leak testing tube Figure 39 T1T24 7e3 Tube desorb mode leak testing trap A Figure 40 TT24 7e3 Tube desorb mode tube purge QUI 1016 V2 2 Aug 06 8 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com 29 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 TT24 7 User Manual Figure 41 TT24 7e3 Tube desorb mode tube desorption Figure 42 TT24 7e3 Tube desorb mode trap A purge Figure 43 TT24 7e3 Tube desorb mode trap desorption Figure 44 TT24 7 software top level screen Figure 45 Location of status LEDs and front panel switch on TT24 7 Figure 46 Download activity timeout dialogue box Figure 47 Ports tab in options configuration Figure 48 TT24 7e1 User interface Figure 49 Flow display showing flow direction through solenoid valves Figure 50 Instrument status bar TT24 7e1 Figure 51 Software icons and menu items for configurations e1 Figure 52 Options dialogue box gas tab Figure 53 Options dialogue box ports tab Figure 54 Options dialogue box syste
23. GC becomes ready The extended sampling time can be limited to a fixed time period by entering a Time to extend sampling and ticking the Enable Timeout box As a result of extended sampling the amount of sample in the trap will be greater than that if extended sampling had not occurred The analytical result will therefore be greater and this may need to be compensated for in the final quantitative data The No Back Valve box should be checked this configures an e1 system Gas Ports System E Mail JV Enable E Mail Alerts m E Mail Settings Username Password Send To Name TT24elsystemt EMailAddress TT247etsysteml serverl com Outgoing Server 92193101 tt t lt sSOsS C T1274 Location Building 1330 Air Con System IV Outgoing E mail server requires authentication If you want to send an e mail to more than one recipient then separate each e mail address using e g one example com two example com s ystem Operator jtechnicalsupport company com service company com Figure 55 Options dialogue box email tab This screen enables alert emails to be generated should the TT24 7 system encounter a problem This could be due to a set point value not being controlled accurately due to a system fault The nature of the fault date and time it occurred appear in the Report deviation screen of the top level software The email alert facility has to
24. UTD 5093 heated over its entire length by means of a distributed heater and at the GC end by heat conduction from the GC oven QUI 1016 V2 2 Aug 06 98 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International The line is 1 m long which is sufficient to reach most gas chromatographs even when a mass spectrometer is attached Most GCs have access points built into the oven region by means of holes in the side top or back of the oven skin with knock out sections in the outer casing and one of these should ideally be utilised to install the transfer line If all such access points are already in use it is possible to gain entry via an unused injector or detector port with or without a heated zone The general approach is illustrated in the three diagrams figures 72 73 and 74 GC oven insulation Silicone foam PTFE protective sleeve tubing 0 25 mm I D fused silica End of line heater Figure 72 Installation of transfer line through inner wall of GC oven Note In all cases the fused silica and PTFE sleeve tubing are fitted as the final operation Locate a hole in the inner oven wall with a corresponding hole leading to the outside of the instrument It is usually necessary to displace the oven insulation material to enable the flexible metal line to be pushed against the outside of the inner oven wall If the GC oven wall insulatio
25. be enabled by checking the Enable eMail Alerts box Note Some of the items in this section of the software may have to be QUI 1016 V2 2 Aug 06 Markes International Ltd 75 T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International provided by the corporate IT department eMail Settings Name This can be any descriptive name for the system in use Where multiple TT24 7 systems are employed a unique identifying name per system is advised for accurate tracking email Address This is the email address of the PC system connected to the TT24 7 Outgoing Server The Internet Protocol IP address of the server used by the PC must be specified here T1247 Location This is an important item as it identifies the exact location of the TT24 7 which has sent the email alert It is recommended to make this section as clear and descriptive as possible Outgoing E mail server requires authentication If the Outgoing E mail server requires authentification the box is checked as shown above However the alert email will not be sent unless a Username and Password are typed If the box is unchecked i e no authentification is required then the alert email is automatically generated and sent Send to This defines to whom the email is sent This could be a single person or consist of multiple email addresses Each address has to be separated by a semi colon eMail alert
26. followed by a plug of glass wool then the stronger sorbent Again this ensures that when air is drawn through the tube the mixture reaches the weaker sorbent first where the higher boiling components are trapped Note that if sampled tubes are to be stored for some time for transportation or other purposes then method 1 is preferred After sampling the tube train can be dismantled and each tube capped with long term storage caps Long term storage of tubes containing two or more sorbents is not recommended as higher boiling components may migrate from the weaker to the stronger sorbent over time and this can cause incomplete desorption when the tubes are eventually analysed If the multi sorbent tubes are to be stored for longer than one week then the following procedure must be undertaken take the samples in the normal way and cap with 1 4 brass storage caps in the field as usual place the tubes in an air tight container e g Tupperware box or clean tin can with lid and place in a clean refrigerator when the tubes have reached the cold temperature briefly remove them from the refrigerator and check and re tighten the caps due to the difference in the thermal properties of brass and stainless steel the caps may have become slightly loose return the samples in their container to the refrigerator immediately prior to analysis remove the tubes from the refrigerator and allow them to come to room temperature before analys
27. from the menu bar select File gt Open and then the required method The file suffix is smth Step 2 Preparing the GC GCMS to accept an external TT24 7 Start Signal The TT24 7 initiates the GC GCMS and associated software by sending a remote start signal at the point where the trap fires and releases its retained sample Prepare the GC or GCMS method or sequence including any data file name and storage location so that on receipt of the start signal from the TT24 7 the analytical system commences Step 3 Check system ready status Review the TT24 7 status bar at the base of the software to ensure all temperatures and flows are stable and at their set point The GC GCMS system status should also be ready QUI 1016 V2 2 Aug 06 13 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Step 4 Start run Press the Start Run icon on the menu bar this will initiate the TT24 7 continuous sampling mode Initially this will be on to trap A during which time trap B purges and trap fires in readiness for the first sample volume coming from trap A 1 1 2 Creating a new TT24 7 method Creating a new TT24 7 method follows a similar stepwise path which then leads into the process described above for an existing method section 1 1 1 Step 1 Choose the sampling mode The first step to creating a new method is selection of the sampling mode as
28. lifted up With the lever in the up position a tube can be positioned into the oven It is important that the tube is orientated correctly the grooved end of the tube should be towards the back of the instrument With the tube in place the sealing mechanism lever can be lowered which seals the tube into the flow path When sealing the tube into place take care that the tube is aligned with the sealing o rings to prevent any o ring damage being incurred Any damage to the o rings could lead to a tube leak test failure Removal of the tube is a very similar process First lift the sealing mechanism lever to provide access to the tube and then pull the tube out by hand from the sealing o ring see figure 89 If the tube is difficult to extract from the sealing o ring then the tube extractor can be used to provide extra grip Figure 89 TT24 7e2 e3 system removing desorb tube QUI 1016 V2 2 Aug 06 113 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 6 Installation removal of split tube e3 The split tube is located on the right hand side of the TT24 7 when looked at from the front of the instrument figure 93 The split tube is either a charcoal split tube which traps any split volatiles and prevents them from being passed back into the laboratory atmosphere Or alternatively when in Tube Desorb mode the split tube can be replaced by a conditi
29. message The email alert contains the following type of information This is an automated message which has been sent as an error has occurred with the TT24 7 Please see the details below Problem Transfer Line Over Temperature Date 14 02 2005 10 45 41 Name TT24 7el_system 1 Location Building 1330 Air Con System 1 This provides sufficient information to identify the nature of the problem the system at fault and its precise location As the PC system connected to the TT24 7 could be part of a company organisation internal network then remote access software could be initiated at this point and the diagnostic section of the TT24 7 software accessed This could provide a clearer insight into the problem before dispatching repair personnel 2 9 1 6 User diagnostics User diagnostics allows the user to manually manipulate the valves both heated valves and solenoid valves in order to assist in tracking down a leak in the system see section 4 1 It is accessed from the View menu item section 2 9 1 4 2 above QUI 1016 V2 2 Aug 06 76 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Selecting Diagnostics opens a password Dialogue Box enter the password flowonly and this will open the diagnostics screen figure 56 Clicking on any of the valves will cause the valve to move e g move UP from DOWN or OFF from ON
30. packed column Pack the chromatographic column with a known weight of the sorbent of interest Operate the column at a range of temperatures between 150 C and 250 C Inject the analyte in question and note the retention time and column flow at each temperature From this information calculate the specific retention volume in litres per gram for each temperature Plot the log of the specific retention volume against the reciprocal of the absolute column temperature which gives a linear relationship The slope of the graph may be extrapolated to give the log of the retention volume at 20 C The retention volume may then be calculated In order to ensure that there is absolutely no chance of any breakthrough occurring during a sampling procedure if for example the ambient temperature were to rise a Safe Sampling Volume SSV is usually quoted as being half the retention volume A sampling strategy which limits the volume of air sampled to the SSV or less is therefore considered to be prudent Note also that safe sampling volumes on some sorbents particularly those with some hydrophillicity are significantly impacted by high atmospheric humidity For example SSVs on Spherocarb UniCarb and Carbosieve SIII should typically be reduced by a factor of 10 at 80 RH and above Sampling in a mixed atmosphere It is often the case that the list of analytes to be monitored requires more than one sorbent For example if both toluene and meth
31. pneumatic control module EPC of the associated GC system This demand will be based on the carrier gas flow into the capillary column and any split flow or purge gas requirements which are configured and specified during the process This includes the needle valve regulated split flow and dry purge flow values QUI 1016 V2 2 Aug 06 31 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 1 TT24 7e1 hardware configuration TT24 7el1 can only be operated in the continuous sampling mode 2 5 1 1 Standby MFC amp Pump Sample in KEY Flow of Carrier Gas Carrier Gas no flaw gt _ Flow of Sample Gas Sample Gas no flaw Figure 15 TT24 7e1 Standby In this non sampling mode carrier gas alone is continuously supplied to the capillary column No other gas flow occurs within the TT24 7 unit during this time QUI 1016 V2 2 Aug 06 32 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 1 2 Trap A sampling trap B purging KEY Flow of Carrier Gas Carrier Gas no flaw gt Flow of Sample Gas Sample Gas no flaw Figure 16 TT24 7e1 Trap A sampling trap B purging By starting the TT24 7 software the continuous sampling process commences The date and time that the sampling started and the trap that i
32. restricted end Figure 11 TT24 7 cold trap note the restricted inlet outlet end and the quartz collar on the unrestricted end Backflushing the trap allows the use of multiple sorbent beds in the trap each bed having a different sorbent strength with the weaker sorbent at the start of the trap An example would be Tenax TA followed by HayeSep D or Chromosorb 106 etc This sequence of sorbent materials allows for a much broader range of analytes to be retained on the trap over that for a single bed However greater consideration is then required in terms of maximum operating temperature as many sorbents have quite different maximum upper temperature values See Appendix 3 for further information regarding sorbent selection and sorbent maximum temperatures Backflushing the traps allows each analyte to come off the retaining bed alone without contact with a stronger sorbent material which could be irreversible or detrimental to peak shape Note Installation and removal of the cold traps is a user operation However it is necessary to follow the instructions carefully to avoid damaging the traps Full instructions are given in section 3 4 Collared traps are compatible with the TT24 7 Trap Extraction Tool TTD 5032 Note You may have TT24 7 traps in stock which are of an earlier design with NO collar on them these traps may be used in your TT24 7 system but are not compatible with the Trap Extraction Tool extra care
33. so sufficient time must be given for the tube oven to reach its desired set point and stay at this value for at least 1 minute 2 9 2 1 8 Desorb temp available in tube desorb mode This is the upper tube set point temperature Values ranging from 50 C to 350 C are possible however the upper value should not exceed the maximum temperature for the sorbents used If a mixed bed sorbent tube is used the upper value should not exceed the lowest of the maximum temperatures See Appendix 3 for details Note If you exceed the maximum sorbent temperature the resulting breakdown of the sorbent may severely contaminate the flow path of your system This may require the complete replacement of the flow path and associated components by a fully qualified service engineer and would not be covered by the instrument warranty 2 9 2 1 9 Trap A B available in tube desorb mode This selects which trap is used for sampling i e onto which trap A or B the desorbed or injected sample is passed 2 9 2 1 10 Trap low temperature available in both sampling modes This is the lower trap temperature value used to retain compounds on the sorbent bed Values ranging from 15 to 50 C are possible Sub ambient values are possible as a consequence of the Peltier cooling elements situated immediately below each trap QUI 1016 V2 2 Aug 06 81 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual M
34. that analytical data can be produced in the shortest time interval This is facilitated by sampling directly onto a cold trap for single stage enrichment This ultimately leads to near real time analysis NRT where all the sampling parameters are running within the shortest time frame and all the analytical conditions are optimized for high speed chromatography Time frames as short as 5 minutes are possible with NRT Off line analysis is therefore used for ultra low level sampling over extended time periods i e 8 hr time weighted average TWA whereas on line analysis is used for detecting potentially harmful levels at extremely low concentrations in the shortest time frame The main rate limiting step in a single trap TD system for on line analysis is the cool down time of the trap During this phase which can last for 5 minutes no sample can be adsorbed onto the trap For most applications this is quite adequate and combined with high speed GC provides for excellent on line analysis However for certain compounds i e chemical warfare agents CWA and certain toxic industrial chemicals TIC this time frame is still too long because of their extreme toxicity to the human population Ultimately a sampling regime is QUI 1016 V2 2 Aug 06 15 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International required which is continuous with no time blind spots To a
35. through the trap Sample gas the composition of the sample gas as configured in the options section 2 9 1 5 1 is shown typically air Carrier gas the composition of the carrier gas as configured in the options section 2 9 1 5 1 is shown typically Helium 2 9 1 4 Software icons and menu items In the header section of the top level software there is a menu bar and a series of icons as shown in figure 51 1124 7 Control File wiew Instrument Help D e W gt E Figure 51 Software icons and menu items for configurations e1 2 9 1 4 1 Software icons G Creates a new method which starts with default parameters Opens the method subdirectory so that an existing method can be loaded into the TT24 7 4 H Requests a method file name to be saved into the methods sub directory No suffix is required as the mth suffix is automatically added a Starts a TT24 7 run with the loaded method conditions Opens the Stop Run dialogue box which asks whether you wish to Stop Immediately or Continue running QUI 1016 V2 2 Aug 06 70 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 1 4 2 Menu bar File 1124 7 Control File View Instrument Hel L New Se Open Save Ctrl S Save As Ctri Alt 5 Simple Mode Exit Ctrl x New Open Save Save As Exit View 1124 7 Control File
36. top of the method window QUI 1016 V2 2 Aug 06 82 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International When the desired method parameters have been specified they can be saved directly into the active method by clicking on the SAVE button at the bottom of the user interface 2 9 2 1 14 Split available in both sampling modes Note The Enable Trap Split checkbox is only available with TT24 7e3 hardware configurations and when the split has been configured in Options section 2 9 2 5 When enabled this function opens the split solenoid valve SV7 see figure 37 in section 2 5 3 2 1 at the point of trap fire and splits the sample in proportion to the split flow rate and column flow rate see section 2 3 3 2 9 2 2 Flow Display The flow display window figure 59 is designed to help the user see the flow direction process and the current run status of the TT24 7 system The diagram shows the flow direction through the solenoid valves SV1 2 3 4 5 and 6 the flow direction through the heated valves HVA HVB HVC the flow through the traps A and B and the flow through SV7 solenoid valve in a TT24 7e3 configuration if the split is enabled see 2 8 2 1 14 Desorption Tube Figure 59 Flow Display showing flow direction through solenoid valves 2 9 2 3 Instrument status bar Instrument Status Heated Zones GC Flow Controller Tra
37. tube some analytes can diffuse into the side arm causing measurable peak tailing The 0 25 mm I D fused silica transfer line must be installed through the union and on into the narrow bore part of the inert coated stainless steel tube When connecting the transfer line to the TT24 7e1 pull about 20 cm of fused silica from the PTFE line casing Slide a ic inch stainless steel Swagelok nut and a te inch x 0 4mm ferrule Supplied with shipping kit see Appendix 1 onto the end of the fused silica and then cut off the first few mm of fused silica Feed the fused silica into the top of the union and slide the ferrule into position Screw the nut onto the union and with the fused silica still loose position it so that the fused silica is inserted around 20 mm into the union Tighten the nut to trap the fused silica and then tighten a further half turn using one of the 8 mm wrenches spanners provided in the shipping kit Do not over tighten or the ferrule will become distorted Carefully bring the clamp plate PTFE plate and shield tube down into position shown in figures 79 amp 80 with the shield tube covering the union nut The shield tubing should be positioned such that the isc inch side tubing projects through one of the cutouts As the transfer line is lowered into position the clamp plate and PTFE plate should fit onto the two exposed threads Use two M4 nuts supplied with shipping kit to lock the PTFE plate onto the exposed threa
38. view Instrument O Options Diagnostics Options Creates a new method which starts with default parameters Opens the method subdirectory so that an existing method can be loaded into the TT24 7 Saves the current TT24 7 parameters directly into the loaded method Requests a method file name to be saved into the methods sub directory No suffix is required as the mth suffix is automatically added Immediately closes down the TT24 7 software Accesses the 1124 7 configuration software see section 2 9 1 5 for details Diagnostics Accesses two levels of diagnostic software for the TT24 Instrument B 1124 7 Control File view Instrument D EP Run Run Stop QUI 1016 V2 2 Aug 06 7 flow only user diagnostics and full service engineer diagnostics see section 2 9 1 6 Starts the TT24 7 with the loaded method conditions Opens the Stop Run dialogue box which asks whether you wish to Stop Immediately or Continue running 71 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 1 5 Options Options is the principle configuration section for the TT24 7 system It is accessed from the View menu item section 2 9 1 4 2 above Within Options there are three separate configuration screens 2 9 1 5 1 Gas Gas Ports System E Mail PSI Pressure Units f kPa Carrier Gas
39. will display the current flow rate from the MFC in the status bar Limit Sample Time I Enable Enabling this option will force the instrument to take a sample only for the specified sampling time No more gas will be sampled until the next sampling cycle Sampling Extended Timeout Time to extend sampling X IV Enable Timeout Valves IV No Back Valve Cancel Figure 54 Options dialogue box system tab Display flow If the enabling box is checked the mass flow controller flow rate and associated values are displayed in the top level status bar see section 2 9 1 3 4 Limit Sample Time This option fixes the sampling time in continuous sampling mode No extended sampling will take place if the GC is not ready when this is active see 2 9 1 1 5 for further information regarding sample time Sampling Extended Timeout In continuous sampling mode the TT24 7 checks on the GC ready status at the completion of the sampling time If the GC is ready then the system continues into dry purge and then trap fire However if the GC system is not ready e g the oven has not cooled down to its set point value and equilibrated then the TT24 7 will automatically go into an extended sampling QUI 1016 V2 2 Aug 06 74 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Valves 2 9 1 5 4 eMail Markes International mode until the
40. within QUI 1016 V2 2 Aug 06 27 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International the TT24 7 the column pressure remains at the defined value determined by the GC method Normally this is a constant pressure value however in certain circumstances pressure or flow programming may be required By controlling the pressure at the head of the column the retention time of compounds eluting from the column will be fixed Chromatographically this is highly advantageous as it produces reproducible retention times for each compound in all analyses This ultimately leads to the generation of absolute retention time databases for compound identification Closed loop feedback is particularly important when the sample is being split The split flow passes through the rear heated valve and out via a needle valve for control as discussed in section 2 3 3 This is immediately adjacent to the point where the transfer line leading to the capillary column enters the TT24 7 and without electronic control would directly affect the column head pressure i e as the split flow increased the head pressure would decrease and compound retention times would vary accordingly The pressure at this point is monitored by the pressure sensor within the GC flow module this sensor subsequently controls the total flow being delivered into the TT24 7 This process is closed loop feedback
41. 016 V2 2 Aug 06 92 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 1 1 TT24 7 power cable ON OFF switch The power cable is inserted into the power supply socket at the rear of the TT24 7 and the system is switched on using the adjacent ON OFF switch The location of this connection and switch is shown in figure 67 The power is supplied to the system when the ON OFF switch is in the depressed state To turn the TT24 7 OFF press the ON OFF switch so the depressed state is O 3 1 2 Communications and Remote start cabling Figure 67 shows the rear of the TT24 7 illustrating the location of the sockets for the two RS232 communication cables the remote start cable and the power cable 1343990 PEPR rr Remote start cable connection Serial cable 1 Sampler Power ON OFF switch Serial cable MFC Unused connection Figure 67 Rear view of TT24 7 showing system cabling connections Figure 68 shows a close up of the labelling on the back of the TT24 7 Note that the label also shows the pneumatic connections into the TT24 7 Additional useful information such as the power requirements and instrument serial number for the TT24 7 are also shown here QUI 1016 V2 2 Aug 06 93 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Figure 6
42. 2 1 Method parameters 2 9 2 1 1 Mode 2 9 2 1 2 Prepurge time available in both sampling modes 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 2 9 2 1 3 Flow path temp available in both sampling modes 1 4 Sample flow rate available in TT sampling mode 1 5 Sample time available in TT sampling mode 1 6 Desorb flow available in tube desorb mode 1 7 Desorb time available in tube desorb mode 1 8 Desorb temp available in tube desorb mode 1 9 Trap A B available in tube desorb mode 1 10 Trap low temperature available in both sampling modes 1 11 Trap high temperature available in both sampling modes 1 12 Trap hold time available in both sampling modes 1 13 Save available in both sampling modes 1 14 Split available in both sampling modes 2 9 2 3 Instrument status bar 2 9 2 3 1 Instrument Status 2 9 2 3 2 Heated Zones 2 9 2 3 3 GC 2 9 2 3 4 Flow controller 2 9 2 4 Software icons and menu items 2 9 2 4 1 Software icons 2 9 1 4 2 Menu bar 2 9 2 5 Options QUI 1016 V2 2 Aug 06 4 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com Markes International 73 74 75 76 77 78 78 78 78 78 78 79 79 80 80 81 81 81 81 81 82 82 82 83 83 84 84 84 85 85 85 86 87 TT24 7 User Manual Markes International 2 9 2 5 1 Gas 2 9 2 5 2 Ports 2 9 2 5 3 System 2 9 2 6 User diagnostics 2
43. 4 7 Thermal Desorption System where more detailed knowledge and understanding is required Section 3 User Installed Components and Maintenance Section 4 Troubleshooting There are three TT24 7 hardware configurations available from Markes International A visual inspection of the unit will ensure that you know which configuration you have prior to reading this manual TT24 7e1 basic system configured only for continuous sampling QUI 1016 V2 2 Aug 06 11 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual QUI 1016 V2 2 Aug 06 Markes International Ltd T 44 0 1443 230935 Markes International TT24 7e2 standard system configured with the following additional features tube desorption pre purge to vent dry purge leak test Note the presence of the tube desorption oven on the left hand side of the trap box indicates that this is an e2 system TT24 7e3 standard system configured with the following additional features tube desorption pre purge to vent dry purge split capability Note the presence of both the tube desorption oven on the left hand side and the split tube on the right hand side indicates that this is an e3 system F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 1 0 Quickstart Guide using the TT24 7 This section is in support of the Quickstart Guide to Operating t
44. 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Needle valve to control split flow Split vent line Figure 6 TT24 7e3 showing the tube desorb and split accessories fitted The split ratio is then a function of the column flow relative to the total flow entering the trap Split Ratio Column Flow Column Flow Split Flow An additional benefit of split mode sampling is the increase in carrier gas flow rate passing through the trap during the trap fire phase This will be considerably higher than in splitless mode where the flow through the trap is equal to column flow Depending on the column detector this ranges typically from approximately 10 mL min down to 3 mL min The increase in flow is directly proportional to the split flow and results in a faster movement of retained sample from the sorbent bed into the column This allows for higher initial operating temperatures in the capillary column as the band width of sample entering the column will be much sharper In splitless mode the column needs to be cooler to promote an efficient focusing effect on the stationary phase This is a standard procedure for splitless injection The flow schematics for the split configuration e3 are shown in section 2 5 3 2 4 Principle system components The main functional components of the TT24 7 excluding electronics consist of 2 4 1 Valving assembly 2 4 2 Pneumatics module QUI 1016 V2 2 Aug 06
45. 6 84 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 2 3 4 Flow controller This component of the status box is not shown by default and requires configuring within the TT24 7 software see section 2 9 2 5 3 When configured following information is given Flow rate the sample flow as follows Trap A B TT Sampling mode Tube desorb flow tube desorb mode Sample gas the composition of the sample gas as configured in the Options section 2 9 2 5 3 is shown typically air Carrier gas the composition of the carrier gas as configured in the Options section 2 9 2 5 3 is shown typically He 2 9 2 4 Software icons and menu items In the header section of the top level software there is a menu bar and a series of software icons figure 61 1124 7 Control File View Instrument Help Ce HE a Figure 61 Software Icons and menu bar for configurations e2 e3 2 9 2 4 1 Software icons i Creates a new method which starts with default parameters a Opens the method subdirectory so that an existing method can be loaded into the TT24 7 r Requests a method file name to be saved into the methods mj sub directory No suffix is required as the mth suffix is automatically added p Starts a TT24 7 run with the loaded method conditions Opens the Stop Run dialogue box which asks whether you wish to Stop Immediately or Con
46. 7 User Manual Markes International 2 9 1 User interface for TT24 7e1 hardware configurations Figure 48 shows the user interface for the TT24 7e1 hardware configuration Only one sampling mode is available in this configuration TT Sampling Method default mth modified Mode Purge Flow Path Temp C 4 Prepurge Time HY and TL 120 0 TT Sampling 1 0 min Sample Flow Rate Trap Low Temp 500 0 ml min 25 0 C Sample Time Trap High Temp 10 0 min 100 0 C Trap Hold Time 10 0 min Figure 48 TT24 7e1 User interface 2 9 1 1 Method parameters At the top of the method window is shown the active method name e g default mth and its status i e whether or not it has been modified from its original set point values The set point values used in the interface are described below 2 9 1 1 1 Mode The sampling mode cannot be changed in the software it is set to continuous sampling TT Sampling as this is the only mode of operation 2 9 1 1 2 Prepurge time This is the pre purge time when carrier gas is passed through the trap just prior to trap fire This purge in the desorption direction is to purge air moisture from the trap after sampling and the flow is equivalent to the column flow which should be at least 3 mL min The pre purge can be set between 0 and 99 9 minutes in increments of 0 1 minute and is typically 0 5 to 1 minute although this can be reduced where the cycle t
47. 8 TT24 7 labelling One of the 9 pin serial RS232 cables connects into the Sampler port of the TT24 7 This communicates with the analyzer part of the TT24 7 for instrument control This cable leads back to the PC either directly into a serial communication port COM1 COM2 etc in the PC or via a USB hub The COM port assignment is selected within the TT24 7 software see section 2 9 1 5 2 2 9 2 5 2 Ports The second serial cable connects into the MFC connector of the TT24 7 This is the mass flow controller connection port and all flow related values within the TT24 7 system are controlled and monitored via this cable connection to the PC As for the Sampler connection described above this cable also leads back to the PC either directly into a serial communication port COM2 COM1 in the PC or via a USB hub The COM port assignment is selected within the TT24 7 software see section 2 9 1 5 2 e1 and 2 9 2 5 2 e2 e3 Note that the COM port selection for the MFC and Sampler must be different If the two serial cables become disconnected from the back of the TT24 7 ensure that the correct serial cable is returned to its allocated socket as per the COM settings If the cables are crossed over the TT24 7 will not operate correctly Connection of the 25 pin Remote start cable is made into the I O socket of the TT24 7 This cable is also connected into the associated GC and particularly into the GC Remote start socket Because GC manufa
48. Column flow Split flow If the split function is not enabled then the flow rate through the trap is equal to the column flow rate alone and should be at least 3 mL min QUI 1016 V2 2 Aug 06 60 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 6 Software control and configuration This section reviews the software control and configuration for each of the available TT24 7 hardware configurations The user interface is discussed in detail The 1124 7 software runs as a Windows application using Windows 98 onwards however Windows 2000 or Windows XP is the preferred version If Windows NT is used no USB cable connection is possible as this is not supported by NT Ensure that you have one of these versions of Microsoft Windows installed on the PC prior to installation of the software The software consists of a top level screen containing a set point user interface an active flow schematic a reporting module and a status bar showing set point and actual values figure 44 1124 7 Control Fie Yiew Instrument Help Function icons and DEH pe eee bar Method default mth modified jode lode TT Sampling Inlet Desorption Tube _ Tube Flow Path Temp C pete 0 min HY and TL EEN iw o O o o 05 12 2005 10 491 INFO Samping Started on Trap A User Active interface Reporting flow module schema
49. Desorption Tube Needle N Valve Q He Q MFC amp Pump Sample in N on Trap B Needle Valve Split Tube KEY gt Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow Flow of Sample Gas Sample Gas no flow Figure 42 TT24 7e3 Tube desorb mode trap A purge This is the dry purge phase prior to trap fire to remove any residual air and moisture coming from the tube The flow is controlled by the needle valve attached to SV6 The split line pnuematics through SV7 and its associated needle valve are also purged during this operation The flow through this line is controlled by this SV7 needle valve QUI 1016 V2 2 Aug 06 59 TT24 7 User Manual Markes International 2 5 3 2 7 Trap A desorption MFC amp Pump Sample in Trap B Needle Valve Column Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow Flow of Sample Gas Sample Gas no flow Figure 43 TT24 7e3 Tube desorb mode trap desorption The selected trap is now rapidly heated and backflushed with carrier gas to remove retained analytes from the sorbent bed s into the capillary column If the split function is enabled in the method see section 2 9 2 1 14 then this will occur at trap fire The flow rate through the trap is therefore equal to the column flow plus the split flow through SV7 The split ratio is therefore Split Ratio Column Flow
50. ED Front panel switch Figure 45 Location of status LEDs and front panel switch on TT24 7 To download the firmware follow the stepwise procedure below Step 1 The TT24 7 should be switched on at the back of the instrument with the front panel switch off i e not depressed This should cause the top LED to turn red while the bottom LED remains OFF If however the front panel switch is inadvertently ON i e depressed at this QUI 1016 V2 2 Aug 06 62 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International time both LED s will appear red Correct this by simply turning the front panel switch OFF before continuing Step 2 Start the TT24 7 software within the controlling PC This is achieved by clicking on the system icon The software starts by attempting to detect the sampler board top LED and if successful will begin downloading the firmware The top LED will turn amber at this time indicating the download is in progress If however the top LED remains red after approximately 10 seconds this indicates the sampler board was not detected To correct this turn the main rear power switch off wait 10 seconds and switch on again The TT24 7 software will continue to look for the sampler board and assuming there is not a specific problem within the instrument the firmware download will resume and the top LED turns amber Upon successful c
51. FC amp Pump Trap B KEY Flow of Carrier Gas Carrier Gas no flaw gt _ Flow of Sample Gas Sarple Gas no flow Figure 18 TT24 7e1 Trap A purging trap B sampling After the sampling time for trap A has completed trap A switches into its pre purge mode to sweep out air and moisture prior to trap fire Having cooled to its starting temperature after the first clean up trap fire trap B now goes into its sampling phase The date and time that the sampling started and the trap that is being sampled are reported as an information message in the reporting module of the software see section 2 9 1 7 e g 05 12 2005 10 59 17 INFO Sampling Started on Trap B QUI 1016 V2 2 Aug 06 35 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 1 5 Trap A desorbing trap B sampling MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no flaw gt _ Flow of Sample Gas Sample Gas no flow Figure 19 TT24 7e1 Trap A desorbing trap B sampling Trap A now fires If this is the first run for A this run is treated as a clean up run however if this is a subsequent run then real sample will be transferred across to the capillary column for analysis To see how the time overlap of sampling purging trap fire and cooling occurs relative to the GC oven cycle time please refer to sectio
52. If the split flow is increased the pressure at this point would normally drop however the sensor compensates for this by increasing the total flow into the TT24 7 to provide for the extra split flow and maintain the column pressure Most GC manufacturers have an LCD built into the instrument and information relating to the GC inlet flows can normally be observed One such parameter is the Total Flow delivered by the inlet into the capillary injection port When the inlet flow module is configured with the TT24 7 this Total Flow parameter is now the flow entering the thermal desorption system This provides a mechanism to observe the change in total flow as the split flow is varied i e as the split flow increases this value will also increase in direct proportion When the analysis is splitless i e no split flow the flow rate through the trap is equivalent to the column flow which is typically between 3 to 10 mL min Once again the flow is controlled by the column head pressure and the total flow demand now is approximately equal to the column flow The value may be slightly higher than the exact column flow if a septum purge flow is running 2 4 6 1 Carrier gas connections Manufacturers of GC systems which have the capability of electronic pneumatic control typically have three pneumatic lines leading from the electronic module into the capillary injection port These consist of the carrier gas supply line a septum purge line an
53. Spherocarb is a registered trademark of Phase Separations UK Tenax TA Tenax GR are registered trademarks of Buchem B V The Netherlands UniCarb is a trademark of Markes International Ltd UK QUI 1016 V2 2 Aug 06 137 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com
54. UI 1016 V2 2 Aug 06 78 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Method default mth modified Method default mth modified Mode jag i fen Trapa C TrapB Purge Flow Path Temp C Purge gt gt Flow Path Temp C Prepurge Time 1 0 min TT Sampling TT Sampling Sample Flow Rate Trap Low Temp Desorb Flow Trap Low Temp 500 0 mlmin 25 0 C 500 0 ml min 25 0 EE Sample Time Trap High Temp Desorb Time Trap High Temp 10 0 min 100 0 C 3 0 min 100 0 C Trap Hold Time Desorb Temp Trap Hold Time 10 0 fae 250 0 C 10 0 min L Prepurge Time H and TL 120 0 1 0 min H and TL 120 0 f Split I Enable Trap Split Save Save Figure 58 User interface for each sampling mode TT Sampling for continuous sampling from a stream of gas air see section 2 3 1 Tube Desorb allows the desorption of a sorbent tube see section 2 3 2 2 9 2 1 2 Prepurge time available in both sampling modes This is the time that the trap is dry purged carrier gas passed through the trap in the sampling direction just prior to trap fire This dry purge removes air moisture from the trap after sampling and the flow is controlled by a needle valve SV6 as shown in figure 21 The flow should be typically set to a value of 50 mL min The pre purge can be set between 0 and 99 9 m
55. a specified time out value see section 2 8 1 5 3 is equalled at which point the system stops The GC becoming not ready is typically due to the oven not cooling down as fast as normal and this affects the GC cycle time The sampling time can be fixed to the specified value i e preventing extended sampling within the TT24 7 software Under these conditions if the GC is not ready then after the fixed sampling time the system then waits until the GC becomes ready or again the time out value stops the process See section 2 9 1 5 3 for extended sampling and fixed time sampling 2 9 2 1 6 Desorb flow available in tube desorb mode This is the flow rate of carrier gas which passes through the tube during its primary desorption phase when the tube is heated to transfer the retained sample into the selected trap either Aor B see 2 9 2 1 11 Flow values ranging from 50 mL min to 1000 mL min are possible and typically flow rates of 100 mL min are used 2 9 2 1 7 Desorb time available in tube desorb mode This is the primary desorption time interval values ranging from 0 1 to 10 minutes are possible Within this time frame sample from the tube must pass into the selected trap and the tube must reach and maintain its upper temperature value section 2 9 2 1 8 Values of less than three minutes are therefore not recommended unless the required desorb temperature is very low The heating rate for the tube is much slower than that of the trap
56. allowing different parts of the flow path to be leak checked with an external device such as a helium leak detector see Section 4 1 Before exiting the flow only diagnostic section click the standby button top left hand side this returns all valves to the standby position ready for system operation Diagnostics Pneumatics m Manual Valve Control Standby Out To Column Figure 56 Flow diagnostics screen 2 9 1 7 Reporting module The reporting module figure 57 displays a number of different Information Warning or Error messages All messages detailed below will appear for either Trap A or Trap B if relevant Trap A is used as an example below All error messages are date and time stamped e g 05 12 2005 10 34 54 PR eports 05 12 2005 10 49 31 INFO Samping Started on Trap A Figure 57 Reporting module QUI 1016 V2 2 Aug 06 77 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 1 7 1 Information messages INFO Sampling started on Trap A date and time stamped when sampling started INFO Sampling has been extended on Trap A reported when samping time exceeded the expected time set in the method this is typically due to the GC Ready signal being delayed perhaps due to the oven taking longer than expected to cool down Information messages do not affect the operation of the system in an
57. alyte retained on the trap Valves There are three tick boxes that may be checked Enable Split option for method For TT24 7e3 systems configured with the split option this box should be checked to include this capacity in the method Purge Valve SV6 For TT24 7e2 e3 hardware configurations the SV6 valve box should be checked to configure the purge valve and allow dry purging of the traps No Rear Valve This box should be unchecked for e2 and e3 configurations 2 9 2 6 User diagnostics User Diagnostics allows the user to manually manipulate the valves both heated valves and solenoid valves in order to assist in tracking down a leak in the system see section 4 1 It is accessed from the View menu item section 2 9 1 4 2 above Selecting Diagnostics opens a password Dialogue Box enter the password flowonly and this will open the diagnostics screen figure 65 Clicking on any of the valves will cause the valve to move e g move UP from DOWN or OFF from ON allowing different parts of the flow path to be leak checked with an external device such as a helium leak detector see Section 4 1 Before exiting the flow only diagnostic section click the standby button top left hand side this returns all valves to the standby position ready for system operation QUI 1016 V2 2 Aug 06 90 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Ma
58. and this can compromise the minimum detection limit MDL for that compound If the same compound is run at a lower flow i e 400 mL min as opposed to 800 mL min this can result in a much sharper peak and a significantly better S N ratio even though the amount of analyte trapped is half The science behind this effect is based on the depth the analyte passes into the sorbent and as a consequence how easily it comes off at trap fire It is therefore both compound and sorbent dependant 2 9 2 1 5 Sample time available in TT sampling mode This specifies the time interval for sample to pass into the trap This parameter is directly associated with the sampling flow rate as discussed above to determine the total amount of sample transferred The range for sample time is from 0 1 to 99 9 minutes however values greater than 1 minute will typically be used The sampling time and therefore the sampling volume can be affected by the ready not ready status of the GC system At the completion of the defined set point time value and prior to the system going into the pre purge phase of the trap the TT24 7 monitors the GC ready status If the GC is ready then the pre purge process commences If however the GC is not ready then the QUI 1016 V2 2 Aug 06 80 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International sampling time is extended until the GC becomes ready or
59. anol are to be monitored simultaneously two sorbents one medium weak for toluene and one strong for methanol should be used For diffusive monitoring this can only be achieved by using two or more tubes in parallel and by stringently conditioning the tube packed with the stronger sorbent before re use Pumped monitoring requires QUI 1016 V2 2 Aug 06 135 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International samples to be drawn through the two or more sorbents in series Sampling onto sorbents in series can be achieved in one of two ways 1 Linking together two tubes containing the sorbents required 2 Packing both sorbents as two separate beds in a single tube In method 1 tubes are connected together using 1 4 brass couplings fitted with PTFE combined ferrules The tubes must be connected in series such that the tube containing the weakest sorbent is at the front of the sampling train and all tubes must be oriented such that the sample passes through from the sampling grooved end of each tube This ensures that the higher boiling components in the mixture are adsorbed by the weaker sorbent and eliminated from the sample stream before reaching the strong sorbent In method 2 small plugs of glass wool or sorbent retaining gauzes separate the 2 or three sorbents in a single tube The weaker sorbent is packed at the front sampling end of the tube
60. arkes International The trap minimum value is sensitive to both the flow path temperature described above the flow rate of sample passing through the trap and the temperature of the air sample For example if the flow path temperature is set to 200 C with a fast flow rate i e gt 700 mL min then the trap minimum value may be 25 C or higher at faster flows If additionally the sample gas is above ambient then this minimum value will be higher again Using lower sampling flows will assist this value and can indeed improve on signal to noise for the resulting chromatographic peak see section 2 9 1 1 5 above Ultimately the minimum trap temperature achievable is determined experimentally by reviewing the relationship between the set point and actual values as shown in the status bar and this will be a function of the flow path temperature and the sampling conditions 2 9 2 1 11 Trap high temperature available in both sampling modes This is the upper temperature setting for the trap Values ranging from 50 C to 400 C are possible The upper trap temperature should be set to the optimum value which enables 100 recovery of analytes from the sorbent bed but does not exceed the maximum permissible temperature for that sorbent See Appendix 3 Keeping the maximum trap temperature as low as possible whilst still enabling 100 analyte recovery will extend trap lifetime Note If you exceed the maximum sorbent temperature the resultin
61. aw Flow of Sample Gas Sample Gas no flow Figure 29 TT24 7e2 Tube desorb mode tube desorption The tube is now heated to the temperature set as the Desorb Temp within the TT24 7 method The tube Desorb Flow and Desorb Time parameters control the desorption process The set Desorb Temp value will depend on the sorbent material and should not be set higher than that recommended for the sorbent s in the tube See Appendix 3 for further details on sorbent selection and maximum recommended temperatures Sufficient flow and time should be maintained to completely desorb all analytes from the tube onto the specified trap A or B In the schematic above A is the chosen trap QUI 1016 V2 2 Aug 06 46 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 2 6 Trap A purge Desorption Tube MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no flaw a Flow of Sample Gas Sample Gas no flow Figure 30 TT24 7e2 Tube desorb mode trap A purge This is the dry purge phase prior to trap fire to remove any residual air and moisture coming from the tube The flow is controlled by the needle valve attached to SV6 QUI 1016 V2 2 Aug 06 47 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes In
62. can be sent to the TT24 7 Software Command Start Parameters None Send a command to the TT24 7 to start run Command Stop Parameters None Send a command to the TT24 7 to stop the current run Command LeakTest Parameters None Send a command to the TT24 7 to start a leak test Command will not work unless instrument is in a standby state Command LoadMethod QUI 1016 V2 2 Aug 06 126 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Parameters Method Filename Change the current loaded method on the TT24 7 If the instrument is in standby the method will be changed immediately If the instrument is running the method will be changed at the end of sampling or at the end of the current run Command Split Parameters ON OFF Open or Close the split valve on the TT24 7 Command Mode Parameters TUBEA TUBEB INJECTA INJECTB CONTINUOUS Change the mode of operation of the TT24 7 Changing the mode will not take effect if the instrument is in running mode Command StopFlow Parameters None Sending command will set the sample flow rate to 0 Command ResumeFlow Parameters None Sending command will return the sample flow to the value specified in the method file QUI 1016 V2 2 Aug 06 127 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes Inter
63. chieve this a system containing two traps A and B is required working in tandem so that while one is receiving and focusing sample the other is desorbing into the analytical system The process then alternates between each trap The TT24 7 has therefore been designed as a twin trap system to facilitate NRT analysis 2 2 TT24 7 Hardware configurations There are three TT24 7 hardware configurations available Ensure that you know which configuration you have prior to reading this manual see Introduction TT24 7el1 standard system configured only for continuous sampling TT24 7e2 standard system configured with the following additional features tube desorption pre purge to vent dry purge leak test TT24 7e3 standard system configured with the following additional features tube desorption pre purge to vent dry purge leak test split capability 2 3 Sampling modes Depending on the hardware configuration of your TT24 7 there are two sampling modes available via the User Interface Continuous sampling for continuous sampling from a stream of gas air Tube Desorb allows the desorption of a sorbent tube Note TT24 7e1 only allows the continuous sampling mode of operation TT24 7e2 and TT24 7e3 allow both sampling modes of operation 2 3 1 Continuous sampling Available with hardware configurations e1 e2 and e3 For continuous sampling the TT Sampling mode of operation must be selected in the TT24 7 softwar
64. cturers have different connectors for a Remote Start cable different cables are required for each GC The N C socket is currently not used QUI 1016 V2 2 Aug 06 94 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 1 3 Serial and or USB Cable connections The TT24 7 requires two serial connections with the controlling PC Direct serial connection therefore requires two spare COM ports in the PC However many modern PC systems do not have these serial ports available and may require upgrading with an additional serial card When using Microsoft Windows 98 2000 or XP an extra serial port can be generated using an available USB port and a USB to serial port conversion cable P N U USBSR Note USB communication is NOT possible with Windows NT The standard 9 pin RS232 serial cable is connected between the TT24 7 and the USB Serial conversion cable The conversion cable may be connected directly to a USB port on the PC or if there are insufficient spare USB ports into a USB hub U USBHB which can accommodate up to four connections The hub is then connected directly to one USB port on the PC Figure 69 shows a cabling schematic using direct serial connection from the TT24 7 and the PC and the remote start connection Serial Cable to Sampler connection P N Z 0189 Remote Start Serial Cable to MFC connection P N 2 0189
65. cycle time The sampling time can be fixed to the specified value i e preventing extended sampling within the TT24 7 software Under these conditions if the GC is not ready then after the fixed sampling time the system then waits until the GC becomes ready or again the time out value stops the process See section 2 9 1 5 3 for extended sampling and fixed time sampling 2 9 1 1 6 Trap low temperature This is the lower trap temperature value used to retain compounds on the sorbent bed Values ranging from 15 to 50 C are possible Sub ambient values are possible as a consequence of the Peltier cooling elements situated immediately below each trap The trap minimum value is sensitive to the flow path temperature described above the flow rate of sample passing through the trap and the temperature of the air sample For example if the flow path temperature is set to 200 C with a fast flow rate i e gt 700 mL min then the trap minimum value may be 25 C or higher at faster flows If additionally the sample gas is above ambient then this minimum value will be higher again Using lower sampling flows will assist this value and can indeed improve on signal to noise for the resulting chromatographic peak See section 2 9 1 1 5 above Ultimately the minimum trap temperature achievable is determined experimentally by reviewing the relationship between the set point and actual values as shown in the status bar section 2 9 1 3 and this wil
66. d valve Figure 82 Precise positioning of end of fused silica transfer line If the fused silica terminates in the space above the end of the inert coated stainless steel tube some analytes can diffuse into the side arm causing measurable peak tailing The 0 25 mm I D fused silica transfer line must be installed through the union and on into the narrow bore part of the inert coated stainless steel tube QUI 1016 V2 2 Aug 06 105 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International When connecting the transfer line to the TT24 7e2 e3 pull about 20 cm of fused silica from the PTFE line casing Slide a is inch stainless steel Swagelok nut and a V ie inch x 0 4mm ferrule supplied with shipping kit see Appendix 1 onto the end of the fused silica and then cut off the first few mm of fused silica Feed the fused silica into the top of the union and slide the ferrule into position Screw the nut onto the union and with the fused silica still loose position it so that the fused silica is inserted 50 mm into the union Tighten the nut to trap the fused silica and then tighten a further half turn using one of the 8 mm wrenches spanners provided in the shipping kit Do not over tighten or the ferrule will become distorted Carefully bring the clamp plate PTFE plate and shield tube down into position shown in figures 83 amp 84 with the shield tub
67. d a split vent line When this module is connected to the TT24 7 system only the carrier supply line and septum purge line are used the split vent line is redundant For correct closed loop feedback control the pressure sensor for the inlet must be connected into the septum purge line The carrier septum purge and split vent lines usually connect into the electronic module by means of a single manifold e g Agilent technologies or individual connectors e g Thermo Electron To protect the original gas lines for future QUI 1016 V2 2 Aug 06 28 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International re assembly of the capillary inlet it is recommended that these lines are replaced with additional gas lines rather than being cut Figure 13 shows the back panel on the TT24 7 for connection of the carrier gas supply carrier inlet and pressure monitoring line pressure outlet i a TOLLO E T TS T iiit T TT TOLL TO Pressure outlet Carrier inlet Figure 13 Carrier gas supply connections on the back panel of the TT24 7 A flow diagram showing the additional electronic flow module and gas lines to the TT24 7 is shown in figure 14 and further details are given in section 2 5 Carrier Gas Supply Line GC Pneumatics Module From GC Desorption Tube Pressure sensor Needle HY C i H L gt Septum Purge MFC a
68. d traps The quartz cold traps are fragile and packing them is a skilled task that should be undertaken with care Both traps in the TT24 7 should be identically packed and should be flow tested prior to use to ensure that they have similar impedences For these reasons we recommend the use of Markes pre packed TT24 7 cold traps either one of the application specific traps or cold traps which are custom packed for your specific application 3 4 4 1 Packing cold traps If you wish to pack your own traps Markes supply empty traps for this purpose The traps should be packed from the wider bore end using the following procedure Insert a small plug of quartz or glass wool depending on the application using a suitable flexible tool Pour in the required amount of sorbent s If multiple sorbents are to be used the weakest sorbent should be inserted first followed by the stronger sorbent Sorbents should be separated by small plugs 2 mm of quartz glass wool as above Finish the trap with a 5 mm plug of quartz glass wool A 6 cm length of the trap measured from the point of bore restriction is subjected to full heating cooling power All the trap packing wool plugs except the final wool plug should be within this 6 cm length Note Care should be taken when using tools funnels etc to insert wool and sorbent that the edge surface of the traps are not damaged or chipped in any way as this will prevent them sealing correc
69. ded Conditioning Temperature Recommended Desorption Temperature Notes Markes International Boiling point 50 C to 200 C VOC s within volatility range above 290 C 280 C to 290 C No higher than 290 C Non polar requires extensive conditioning high artefact background 10 Chromosorb 106 range of mesh sizes available Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes Medium 750 n Cs to n Cy gt Boiling point 50 C to 200 C Hydrocarbons benzene volatile oxygenated compounds 225 C to 250 C 225 C to 250 C No higher than 200 C High artefacts 10 ng For trace level analysis condition at 225 C desorb sample tubes no higher than 200 C to reduce background Hydrophobic Inert suitable for labile compounds 11 Spherocarb UniCarb 60 80 mesh only Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes QUI 1016 V2 2 Aug 06 Markes International Ltd T 44 0 1443 230935 132 F 44 0 1443 231531 Strong 1200 also operates on molecular sieve principle C3 to n Cg Boiling point 30 C to 150 C Very volatile compounds e g VCM ethylene oxide carbon disulphide dichloromethane chloromethane Volatile polar compounds e g methan
70. djacent numbers The first represents the actual value and the second the set point value If these two numbers are equal they appear in black font if however the actual value is not at the set point it will appear blue If the TT24 7 is started when any one of these values is blue then the software will enter an equilibrating mode and the run will only commence when the value becomes ready These values have to be equal 2 C tolerance value for the system to become ready The transfer line and heated valves are controlled collectively by the flow path temperature see section 2 9 2 1 3 2 9 2 3 3 GC The cable connecting the TT24 7 to the associated GC see section 3 1 performs two functions Firstly it monitors the GC ready status as specified in the GC interface logic of the TT24 7 software see section 2 9 2 5 2 If the GC set point values are correct and equilibrated and the software for the GC is in a state to accept a start signal from the TT24 7 then the GC will be ready This ready status is relayed to the TT24 7 and observed in the GC status box If the GC is not ready then a Not Ready comment appears When the GC is ready the second function for the cable is to send the start signal from the TT24 7 to the GC at the point of trap fire so it can begin its analytical process If the GC is not ready at the end of the sampling time then extended or fixed time sampling commences see section 2 9 2 5 3 QUI 1016 V2 2 Aug 0
71. ds QUI 1016 V2 2 Aug 06 103 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Figure 79 Moving the clamp plate PTFE plate and shield tube down into position Figure 80 The transfer line installed and the 8 way orange connector plugged in Plug the orange 8 way connector into the socket adjacent to the transfer line connection See figure 80 for the correct orientation of this connector Replace the heated valve box and M4 nuts and re fix the back panel by reversing the procedure above QUI 1016 V2 2 Aug 06 104 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 3 3 2 e2 e3 systems For e2 e3 systems the transfer line inlet is situated at the back of the third heated valve and the transfer line is installed horizontally into this union Figure 81 shows the ic inch stainless steel union into which the fused silica transfer has to be fitted Figure 82 shows a partly sectioned view of this 16 inch union giving an indication of where to position of the end of the fused silica tubing CHCE SA Transfer a installed here Figure 81 Installation of fused silica tubing Carrier bypass Fused silica terminates here drilled out 1 16 inch inert oated stainless steel tubing 0 5 mm bore Analytes from the trap via the heate
72. e Gas samples which are above atmospheric pressure Max 50 psi can be analysed by the TT24 7 system For samples where the pressure is at or below atmospheric pressure a vacuum pump is required to pull the sample through the instrument Sample flow is regulated for all pressures using an internal mass flow controller MFC capable of controlling gas flows from 50 mL min to 1 L min Sample gas is drawn into the TT24 7 through a 1 4 Swagelok fitting on the right hand side of the instrument close to the valving assembly This union could be extended with QUI 1016 V2 2 Aug 06 16 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International additional plumbing to the exterior walls of the TT24 7 to facilitate connection of a remote sample line or sampling bag figure 2 Figure 2 Sample gas inlet on TT24 7 Continuous sampling starts by initiating the TT24 7 control software see section 2 9 which in turn starts regulating the sample flow rate and time of the gas stream to be analysed This results in a total volume of gas sampled onto each trap After the sampling period the trap is purged for a defined period of time to remove residual air moisture After purging the trap the system enters the trap fire phase in which sample is backflushed from the trap into the capillary column Backflushing the trap with carrier gas provides an efficient mechanism to swee
73. e 87 Figure 88 Figure 89 Figure 90 QUI 1016 V2 2 Aug 06 Loosen the back panel screws Remove the M4 nuts Transfer line connection Markes International Precise positioning of end of fused silica transfer line Moving the clamp plate PTFE plate and shield tube down into The transfer line installed and the 8 way orange connector Installation of fused silica tubing Precise positioning of end of fused silica transfer line Aligning the clamp plate PTFE plate and shield tube into position Clamp plate PTFE plate and shield tube in position Plugging in the 8 way connector TT24 7el1 with overlaid schematic showing trap positions and user serviceable parts TT24 7e2 e3 system with Desorb Tube option on LHS TT24 7e2 e3 system tube sealing mechanism lever lifted up TT24 7e2 e3 system removing desorb tube TT24 7e2 e3 system with Split tube option on RHS Markes International Ltd T 44 0 1443 230935 10 F 44 0 1443 231531 E enquiries markes com 101 102 102 103 104 104 105 105 106 106 107 109 112 113 113 114 TT24 7 User Manual Markes International TT24 7 Operators Manual Introduction This user guide has been designed so that the operator of a TT24 7 system can start an analysis as quickly as possible after installation There are four principle sections to the manual Section 1 Quickstart Guide for those users who simply want to start analysing samples Section 2 The TT2
74. e covering the union nut The shield tubing should be positioned such that the is inch side tubing projects through one of the cutouts As the transfer line is lowered into position the clamp plate and PTFE plate should fit onto the two exposed threads Figure 84 Clamp plate PTFE plate and shield tube in position QUI 1016 V2 2 Aug 06 106 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Use two M4 nuts supplied with shipping kit to lock the PTFE plate onto the exposed threads Plug the orange 8 way connector into the socket adjacent to the transfer line connection See figure 85 for the correct orientation of this connector Figure 85 Plugging in the 8 way connector 3 3 4 Coupling the fused silica transfer line to the GC column Return to the GC and connect the column to the end of the transfer line using the quick seal column connector provided with the shipping kit Instructions are included with the connectors Alternatively you may use a inch zero dead volume connector with the appropriate ferrules 3 3 5 User maintenance of transfer line The quick seal column connector should be replaced every time the seal between the fused silica transfer line and the GC column is broken If a zero dead volume connector is being used the ferrules should be replaced as necessary when the connection is broken The fused silica transfer lin
75. e itself and its accompanying PTFE sleeve should be replaced as part of a scheduled program of maintenance Frequency of changing the transfer line will depend entirely on the usage level of the system and the nature of the compounds being analysed In any event it is advised to replace the fused silica transfer line at least annually QUI 1016 V2 2 Aug 06 107 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 4 Installation and removal of Cold Traps Note Never turn on the power to TT24 7 without the cold traps installed 3 4 1 Installing cold traps Refer to Figure 86 Loosen the locating screw on the trap pneumatics before sliding the pneumatics forwards Slide the narrow bore end of the cold traps into the trap box until they touch the o rings in the heated valves 3 5 x 1 5 mm o ring P N U COV35 Switch on the instrument and download the firmware see section 2 8 Allow the heated valves to reach their temperature set point Push the cold traps the remaining 2 3 mm into the heated valve o rings Fit the spacer o rings P N U COV39 onto the end of the trap e For collared traps use two o rings pushed up against the collar e For old style uncollared traps use a sufficient number of o rings to fill the space between the trap valve connector and the trap guides see figure 86 Replace the trap pneumatics at the front of the in
76. eak shape peak splitting Peak broadening particularly of early eluting components is often an early indication that the cold trap packing needs changing The trap sorbent is subjected to rapid heating during the analysis of every sample and should therefore be replaced regularly Normal aging or the desorption of samples containing aggressive compounds can produce activity in the transfer line or in the analytical column itself This results in peak broadening or tailing If this occurs the capillary column or the fused silica insert inside the transfer line should be replaced A poor connection between the transfer line and the analytical column will also distort peak shapes To avoid this the connecting ends of both the column and the transfer line should be cut cleanly using a fused silica column cutting tool The union or connector assembly should be a quartz quick seal connector or an inert zero dead volume fitting recommended for butt connecting capillary tubing Broad peaks can also result from the selection of too strong an adsorbent in the cold trap or from low carrier gas flows through the trap during desorption The gas flow through the cold trap during secondary desorption i e the column flow should be at least 3 ml min for optimum peak widths If a cold trap is loaded with relatively large quantities gt 1 mg of water or solvent flash vapourisation of the solvent or water may result in a temporary pressure surge causing
77. ection configures the flow calibration of the mass flow controller The selection made here is also shown in the flow controller status box 87 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 2 5 2 Ports Gas Ports System E Mail Communications Port Analyser Port cow x MFC Port 7 Baud Rate 57600 x Baud Rate 57600 M GC Interface Logic GCStart out GC Ready in Open Start Open Ready Closed Start Closed Ready Figure 63 Options dialogue box ports tab This screen consists of two sections the communications port and the GC interface logic These two sections control communication between the TT24 7 and the associated PC system and the ready not ready and start signal logic between the GC and the TT24 7 Communications port The TT24 7 has two serial ports at the rear of the instrument as shown in figure 67 section 3 1 These are the serial interfaces for the mass flow controller and the TT24 7 analyser Each port requires its own dedicated communications COM port connection from the PC This can be provided in two ways i e using two separate serial port cables from the PC system or if two serial ports are not available using USB hub and USB to serial connection cables N B Not supported by Microsoft Windows NT See section 3 1 for more details U
78. een the GC and the TT24 7 Communications port The TT24 7 has two serial ports at the rear of the instrument as shown in figure 67 section 3 1 These are the serial interfaces for the mass flow controller and the TT24 7 analyser Each port requires its own dedicated communications COM port connection from the PC This can be provided in two ways i e using two separate serial port cables from the PC system or if two serial ports are not available using USB hub and USB to serial connection cables N B Not supported by Microsoft Windows NT See section 3 1 for more details Under normal circumstances the default baud rate values of 57600 should be used However if there are communications problems then a lower baud rate be specified i e 38400 GC Interface logic This section of the software affects the start stop interaction between QUI 1016 V2 2 Aug 06 73 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International the TT24 7 and the host GC GCMSD system The actual configuration is dependent on the model of GC GCMSD used For Agilent Technologies and Thermo Electron instrumentation the GC Start out and GC Ready in settings should be in the closed state For other GC manufacturers please contact Markes International for details 2 9 1 5 3 System Gas Ports System E Mail m Display Flaw JV Enable Enabling this option
79. eer diagnostics see section 2 9 2 6 Starts the TT24 7 with the loaded method conditions Opens the Stop Run dialogue box which asks whether you wish to Stop Immediately or Continue running 86 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual 2 9 2 5 Options Markes International Options is the principle configuration section for the TT24 7 system It is accessed from the View menu item see 2 9 1 4 2 Within options there are four separate configuration screens 2 9 2 5 1 Gas Gas Parts System E Mail PSI kPa Pressure Units Carrier Gas Sample Gas He air 7 Figure 62 Options dialogue box gas tab This section defines the pressure units and the sample and carrier gas selection Pressure units Carrier gas type Sample gas type QUI 1016 V2 2 Aug 06 The pressure unit selection is either psi or kPa Note 1 psi 101 325 kPa In Tube Desorb mode the desorb pressure is displayed on the instrument status bar see section 2 9 2 3 1 Choices of Helium He Nitrogen N gt Hydrogen H gt and diagnostic air are available The selection made here is shown in the flow controller status box as part of the instrument status See section 2 8 1 3 4 Choices of Air No He Hz safety considerations may apply using this gas and Carbon Dioxide COV are available This sel
80. er Manual Markes International 2 5 3 1 2 Trap A sampling trap B dry purging Desorption Tube q Needle N valve n D O TA Y MFC amp Pump Sample in off Trap B Dr Needle valve Split Tube on _ aw Ne KEY Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow Flow of Sample Gas Sample Gas no flow Figure 33 TT24 7e3 Continuous sampling trap A sampling trap B dry purging By starting the TT24 7 software the continuous sampling process commences The sample passes initially onto trap A The date and time that the sampling started and the trap that is being sampled are reported as an information message in the reporting module of the software see section 2 9 2 7 e g 05 12 2005 10 49 31 INFO Sampling Started on Trap A At the same time trap B dry purges with carrier gas in the sampling direction This removes air and moisture from the trap prior to firing The dry purge flow rate through the trap B at this time is controlled by a needle valve connected to SV6 Carrier gas also purges down the split line to purge any air from the line and to prevent ingress into the system The sample gas flow rate passing into the TT24 7 is controlled by the internal mass flow controller MFC QUI 1016 V2 2 Aug 06 50 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes Internationa
81. eve one or more of the large washers supplied will be needed If the heated zone block is particularly deep both the M6 spacer nut and spacer tube will needed as shown Large washer Silicone foam rubber Heated zone block insulation Large washer Spacer nut M6 Spacer tube Spacer nut M6 Figure 74 Installation of transfer line through heated zone block This part of the line derives its heat from the heated zone block which should be set to run at a conveniently high temperature preferably 50 C above the line setting but not above 250 C as the silicone foam rubber insulation will be damaged The parts supplied can be used in other combinations to suit particular instrument configurations 3 3 2 Installing the fused silica transfer line insert Once the heated line has been fitted to the GC the fused silica plus associated PTFE sleeving P N UTD 5093 see Appendix 1 are pushed from the GC end along the s inch aluminium tube until they protrude from the other TT24 7 end of the transfer line QUI 1016 V2 2 Aug 06 100 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 3 3 Connecting the transfer line to the TT24 7 Place the TT24 7 on the bench on the most convenient side of the GC Ensure that the transfer line will reach from the back of the TT24 7 to the selected entry point into the GC oven 3 3 3 1 e1 systems For e1 sys
82. g breakdown of the sorbent may severely contaminate the flow path of your system This may require the complete replacement of the flow path and associated components by a fully qualified service engineer and would not be covered by the instrument warranty When multi bed traps are being used the maximum temperature that can be set is that relating to the sorbent with the lowest allowable temperature Consideration must then be taken of the recovery efficiency for analytes from sorbents which go to higher values 2 9 2 1 12 Trap hold time available in both sampling modes This is the time interval when the trap is held at its maximum value Time intervals from 0 1 to 10 minutes are possible however values in excess of 0 5 minutes are typically used This value must be long enough to ensure complete removal of analytes from the trap into the analytical column Consideration of the trap flow conditions at trap fire are required i e the flow through the trap at trap fire is equal to the column flow rate which could be as little as 3mL min In this case a time value less than 1 minute is not recommended Incorrect setting of this time can be the cause of poor sensitivity for certain compounds as insufficient time will reduce the amount of sample leaving the trap 2 9 2 1 13 Save available in both sampling modes Once a method parameter has been changed then the word modified appears alongside the method name in the blue bar at the
83. he TT24 7 Software ITSO15 This is a laminated card which is supplied separately with the TT24 7 It is intended to help operators with a quick setup of the system where a more detailed knowledge is not required For the Quickstart approach to work successfully it is assumed that the TT24 7 has been installed and tested by a qualified engineer Quickstart uses a TT24 7 hardware configuration of e2 e3 to demonstrate the running of the system however the instructions are also valid for TT24 7el1 systems More detailed information about the instrumentation and software is supplied in subsequent sections of this document Note Never turn on the power to the TT24 7 system without the cold traps installed see section 3 4 1 1 Running the TT24 7 system The TT24 7 e2 and e3 can be operated in two sampling modes continuous sampling and single tube desorption The TT24 7e1 can only be operated in continuous sampling mode As the principle operating mode for the TT24 7 is continuous sampling this will be included in the Quickstart setup Both sampling modes are discussed in detail later in the manual Section 2 2 1 1 1 Using an existing TT24 7 method Running the TT24 7 system in its continuous sampling mode using an existing method is a simple four step process Step 1 Loading the TT24 7 method To load the required TT24 7 method either click on the menu bar icon at the top of the software screen and select the desired method or
84. hrough the trap Sample flow rates from 50 mL min to 1 L min are possible with 0 1 mL increments however the maximum flow rate is affected by the sorbent bed depth and mesh size Where fine mesh size material is used i e 80 100 mesh or finer the maximum flow rate will be reduced Ultimately the fastest flow rate achievable is determined by specifying the maximum flow rate of 1 L minute and observing the actual flow value on the status bar see section 2 9 2 3 at the bottom right side of the user interface In certain applications where the analyte concentration is very low i e sub ppb and there is a time restriction on sampling i e NRT there is a temptation to set a very fast sampling flow rate to maximise the amount of analyte passing into the trap in unit time For example sampling at 1 L min for 10 minutes results in a sampling volume of 10L If the analyte concentration is very low e g in the pg L concentration i e ppt then a 10L volume would contain sufficient sample in theory for detection by selective GC detectors or by GCMS However sensitivity is very dependant on the signal to noise S N ratio of the resultant chromatographic peak If this is sharp i e peak widths lt 5 seconds then much better integration and detection is possible than for peak widths gt 15 seconds In practice it has been shown that very fast sampling flow rates gt 800 mL min with certain sorbent materials produces poor or broad peak shapes
85. ility range above oxygenated compounds Example Analytes Sorbent Maximum Temperature 250 C Recommended Conditioning Temperature 225 C to 250 C Recommended Desorption Temperature No higher than 225 C Notes High artefacts 10 ng For trace level analysis condition at 225 C desorb sample tubes no higher than 200 C to reduce background levels Low maximum temperature repack tubes after 50 thermal cycles Inert 8 Porapak N range of mesh sizes available Sorbent Strength Medium Specific Surface Area m2 g 300 Approximate analyte volatility range n Cs to n Cg Boiling point 50 C to 150 C Volatile nitriles e g acrylonitrile acetonitrile propionitrile Pyridine volatile alcohols ethanol methyl ethyl ketone Example Analytes Sorbent Maximum Temperature 190 C Recommended Conditioning Temperature 180 C to 190 C No higher than 180 C Notes Hydrophobic High artefacts 10 ng For trace level analysis condition at 180 C and desorb sample tubes no higher than 160 C to reduce background levels Recommended Desorption Temperature 9 HayeSep D range of mesh sizes available Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range QUI 1016 V2 2 Aug 06 Markes International Ltd T 44 0 1443 230935 Medium 795 n Cs5 to n Cy gt F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Example Analytes Sorbent Maximum Temperature Recommen
86. ime of the TT24 7 system needs to be kept to a minimum 2 9 1 1 3 Flow path temp This is the set point temperature for the heated valves and the transfer line to the GC The temperature range extends from 100 C to 200 C The temperature should be set high enough to prevent any condensation of sample within the valve transfer line and values less than 120 C are rarely used However this temperature value will also affect the lower trap temperature value QUI 1016 V2 2 Aug 06 65 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International If the flow path temperature is set to its maximum of 200 C then the trap temperature cannot be controlled at values less than 25 C If the flow path temperature is set to 150 C then a minimum trap temperature of 15 C is possible 2 9 1 1 4 Sample flow rate This specifies the flow rate of sample vapour passing through the traps The sample may be at atmospheric pressure in which case a vacuum pump is required to pull sample into the system The flow rate is then regulated by the internal mass flow controller MFC If the sample is at positive pressure Max 50 psi then the vacuum pump is not required and again the MFC controls the flow through the trap Sample flow rates from 50 mL min to 1 L min are possible with 0 1 mL increments however the maximum flow rate is affected by the sorbent bed depth and mesh size
87. ing this is vital to avoid any problems with condensation Note also that if 2 or more sorbents are to be packed into a single tube all the sorbents must have similar maximum temperatures If one or more of the sorbents has a significant lower maximum temperature than the other s in the tube it will not be possible to stringently condition the more stable sorbents without exceeding the temperature limitations of the less stable material For this reason Chromosorb and Porapak sorbents are not recommended to be used in mixed sorbent bed tubes QUI 1016 V2 2 Aug 06 136 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Long term storage of clean and sampled tubes Conditioned or sampled sorbent tubes should always be stored using 1 4 brass Swagelok type screw caps fitted with combined PTFE ferrules It is recommended that these be tightened by hand plus a further quarter turn using conventional spanners wrenches or ideally a Markes International CapLok tool The Cap Lok tool was invented by scientists at the French Environmental Centre INERIS and prevents over tightening and distortion of the PTFE ferrules It is not necessary to store capped tubes in refrigerated conditions except as stated above If refrigeration is to be used caps must be retightened approximately a quarter turn using the CapLok tool once they have reached their st
88. inutes in increments of 0 1 minute and is typically 0 5 to 1 minute although this can be reduced where the cycle time of the TT24 7 system needs to be kept to a minimum 2 9 2 1 3 Flow path temp available in both sampling modes This is the set point temperature for the heated valves and the transfer line to the GC The temperature range extends from 100 C to 200 C The temperature should be set high enough to prevent any condensation of sample within the valve transfer line and values less than 120 C are rarely used However this temperature value will also affect the lower trap temperature value If the flow path temperature is set to its maximum of 200 C then the trap temperature cannot be controlled at values less than 25 C If the flow path temperature is set to 150 C then a minimum trap temperature of 15 C is possible QUI 1016 V2 2 Aug 06 79 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 2 1 4 Sample flow rate available in TT sampling mode This specifies the flow rate of sample vapour passing through the traps The sample may be at atmospheric pressure in which case a vacuum pump is required to pull sample into the system The flow rate is then regulated by the internal mass flow controller MFC If the sample is at positive pressure Max 50 psi then the vacuum pump is not required and again the MFC controls the flow t
89. ional can supply a secondary pressure regulating accessory P N U GASO01 which regulates both the dry gas and the carrier gas pressure The dry gas is attached at the rear of the instrument to the connector labelled Purge Gas The sample gas typically air will contain both oxygen and moisture The air is removed from the trap just prior to trap fire using the dry purge pre purge gas flow Moisture can also be removed by prudent selection of sorbent material e g Tenax does not retain moisture see Appendix 3 If a hydrophilic sorbent is used the water will be transferred across to the analytical system Split mode sampling where available with e3 systems will reduce this volume 3 2 1 User maintenance for gas requirements Standard good practice should be observed for the maintenance of the gas lines serving the TT24 7 and in particular the replacement regeneration of any filters on the system de oxo filters moisture traps hydrocarbon traps etc Attention should be paid to the manufacturers instructions of these filters with respect to frequency of regeneration replacement 3 3 Installation and removal of heated transfer line 3 3 1 Connecting the transfer line to the gas chromatograph The TT24 7 is supplied with a universal transfer line to deliver desorbed analytes from TT24 7 to a gas chromatograph or other analytical system The sample path utilises a deactivated fused silica line 0 25mm I D and 0 35mm O D P N
90. l 2 5 3 1 3 Trap A sampling trap B desorbing Desorption Tube Needle Valve MFC amp Pump Sample in Neots oft Split Tube on tO Vent G KEY gt Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flaw _ Flowof Sample Gas Sample Gas no flow Figure 34 TT24 7e3 Continuous sampling trap A sampling trap B desorbing The first two runs of the continuous sampling mode i e trap A and trap B would typically not be used for quantitative analysis of the sampled air but as a clean up process for both traps After both traps have been fired once then the subsequent samples may be quantified After purging the trap B for the first time trap fire occurs and flow is directed backflushed across to the capillary column This first B trap fire prepares the trap for subsequent sampling If the split function is enabled in the method see section 2 9 2 1 14 then this will occur at trap fire Trap B Desorbing The flow rate through the trap is therefore equal to the column flow plus the split flow through SV7 The split ratio is therefore Split Ratio Column Flow Column flow Split flow If the split function is not enabled then the flow rate through the trap is equal to the column flow rate alone and should be at least 3 mL min QUI 1016 V2 2 Aug 06 51 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Man
91. l Packing Lists e2 specific parts Description QUI 1016 TT24 7 User Manual Quick Start Guide for TT24 7 software a QUI 1016 V2 2 Aug 06 122 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Packing Lists e3 specific parts Description pee eee A 7 Quick Start Guide for TT24 7 software SERTTD 1044 e2 e3 Inlet support bracket ITS014 TT24 7e3 Quick Reference Guide a QUI 1016 V2 2 Aug 06 123 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Routine Maintenance Spares common parts e1 e2 and e3 systems U FV001 Pk 10 ferrule 16 graphitized vespel 0 4 mm id hole to connect fused silica transfer line to TT24 7 U FV002 Pk 10 ferrules 16 X 1e graphitized vespel use with PEEK tubing i e connection of carrier gas lines U FV003 Pk 10 ferrules s x 16 graphitized vespel U FV005 Pk 10 ferrules s graphitized vespel 2 mm id hole transfer line insert with PTFE sleeve TT24 7 cold trap optimised for high boiling point reactive compounds such as the chemical warfare Agent VX T 2HD TT24 7 cold trap optimised for the chemical warfare agent mustard HD T 3GBGE TT24 7 cold trap optimised for the more volatile chemical warfare agents such as GB and GE the G analog of VX T 6EMP TT24 7 emp
92. l be a function of the flow path temperature and the sampling conditions 2 9 1 1 7 Trap high temperature This is the upper temperature setting for the trap Values ranging from 50 C to 400 C are possible The upper trap temperature should be set to the optimum value which enables 100 recovery of analytes from the sorbent bed but does not exceed the maximum permissible temperature for that sorbent See Appendix 3 Keeping the maximum trap temperature as low as possible whilst still enabling 100 analyte recovery will extend trap lifetime Note If you exceed the maximum sorbent temperature the resulting breakdown of the sorbent may severely contaminate the flow path of your system This may require the complete replacement of the flow path and associated components by a fully qualified service engineer and would not be covered by the instrument warranty When multi bed traps are being used the maximum temperature that can be set is that relating to the sorbent with the lowest allowable temperature QUI 1016 V2 2 Aug 06 67 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Consideration must then be taken of the recovery efficiency for analytes from sorbents which go to higher values 2 9 1 1 8 Trap hold time This is the time interval when the trap is held at its maximum value Time intervals from 0 1 to 10 minutes are possible however values i
93. le consists of three solenoid valves SV1 SV2 and SV3 See section 2 5 for full details of flow schematics QUI 1016 V2 2 Aug 06 23 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International These three way on off solenoid valves control the source and flow direction of gas passing through the traps These flows consist of The sample gas for analysis continuous or tube The carrier gas to backflush the traps The purge gas to flush the traps of air and moisture prior to trap fire SV1 and SV3 are connected to the traps A and B and SV2 connects sequentially to both valves When either SV1 or SV3 are ON they are connecting the associated trap SVi trap A SV3 trap B to the mass flow controller for any of the trap sampling modes discussed in section 2 3 When either SV1 or SV3 are OFF they are either receiving carrier gas from SV2 to backflush the trap at trap fire into the capillary column or they are receiving dry purge gas from the traps to remove air and moisture in the trap 2 4 3 Peltier cooled traps A and B The TT24 7 contains two identical quartz cold traps which are located within the trap housing figure 10 The two traps lie parallel to each other and connect at one end into a heated valve and at the other end into the pneumatics assembly The location of the trap box is shown in Figure 9 Trap A Figure 10 Position of Trap A and Tra
94. lied to the capillary column No other gas flow occurs within the TT24 7 unit during this time QUI 1016 V2 2 Aug 06 54 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 3 2 2 Leak testing tube MFC amp Pump Sample in Trap B off iii Needle valve Split Tube KEY gt Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow gt _ Flow of Sarnple Gas Sample Gas no flow Figure 38 TT24 7e3 Tube desorb mode leak testing tube The first stage in tube desorption is a tube leak test This is essential as the tube has been inserted into the TT24 7 flow path and sealed with two retaining o rings one at the front and back of the tube oven See section 3 5 for tube installation instructions During this phase the tube desorption flow lines in the TT24 7 are initially pressurised with carrier gas and then solenoid SV5 is switched OFF to seal the system The heated valves are configured so that there is no connection beyond HVC The pressure sensor P adjacent to SV5 is monitored to measure the rate of pressure decay If this is acceptable lt 5 drop in pressure within 30 seconds the software moves on to the next phase in the tube desorption process QUI 1016 V2 2 Aug 06 55 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes I
95. low controller flow rate and associated values are displayed in the top level status bar see section 2 8 1 3 4 This option fixes the sampling time in continuous sampling mode No extended sampling will take place if the GC is not ready when this is active see 2 8 1 1 5 for further information regarding sample time Sampling Extended Timeout In continuous sampling mode the TT24 7 checks QUI 1016 V2 2 Aug 06 Markes International Ltd on the GC ready status at the completion of the sampling time If the GC is ready then the system continues into dry purge and then trap fire However if 89 T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International the GC system is not ready e g the oven has not cooled down to its set point value and equilibrated then the TT24 7 will automatically go into an extended sampling mode until the GC becomes ready The extended sampling time can be limited to a fixed time period by entering a Time to extend sampling and ticking the Enable Timeout box As a result of extended sampling the amount of sample in the trap will be greater than that if extended sampling had not occurred The analytical result will therefore be greater and this may need to be compensated for in the final quantitative data The total sampling volume is reported in the reports deviation screen which allows the re calculation of the correct amount of an
96. lumns are available which have a built in length of uncoated tubing at the end of the column This length can be inserted through the PTFE sleeve described above and connected directly into the TT24 7 The advantage of this method is the exclusion of a connector within the transfer line which may be the source of problems with leaks or activity see Section 4 Troubleshooting for further details The disadvantage of this technique is that changing columns needs disconnection at the TT24 7 fitting and removal from the transfer line Where a single column is likely to be used consistently the latter approach is recommended where multiple columns are to be used in an interchangeable manner the former is advised 2 4 5 Tube desorption and sample split pneumatics These sampling options have been discussed in general in section 2 3 2 and 2 3 3 Additional information can be found in section 3 0 User Installed Components and Maintenance and the sampling schematics can be found in section 2 5 2 4 6 Electronic pneumatic control EPC Two gases pass into the TT24 7 system during its operation excluding the trap box purge flow namely carrier gas and sample gas The sample gas is typically air however other gas types can be accommodated i e nitrogen hydrogen helium and carbon dioxide Control of the sample gas flow rate is achieved using an internal mass flow controller with an operating range from 50 mL min to 1 L min The gas type must be s
97. m tab Figure 55 Options dialogue box email tab Figure 56 Flow diagnostics screen Figure 57 Reporting module Figure 58 User interface for each sampling mode Figure 59 Flow Display showing flow direction through solenoid valves Figure 60 Instrument status bar e2 e3 configurations Figure 61 Software Icons and menu bar for configurations e2 e3 Figure 62 Options dialogue box gas tab Figure 63 Options dialogue box ports tab Figure 64 Options dialogue box system tab Figure 65 Flow diagnostics screen Figure 66 Reporting module Figure 67 Rear view of TT24 7 showing system cabling connections Figure 68 TT24 7 labelling Figure 69 Direct serial connection Figure 70 USB connection Figure 71 Cable connections including power recycle box Figure 72 Installation of transfer line through inner wall of GC oven Figure 73 Installation of transfer line through fan protection grill Figure 74 Installation of transfer line through heated zone block QUI 1016 V2 2 Aug 06 9 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com Markes International 58 59 60 61 62 63 64 65 68 68 70 72 73 74 75 77 77 79 83 83 85 87 88 89 91 91 93 94 95 96 97 99 100 100 TT24 7 User Manual Figure 75 Figure 76 Figure 77 Figure 78 Figure 79 position Figure 80 plugged in Figure 81 Figure 82 Figure 83 Figure 84 Figure 85 Figure 86 Figur
98. m the sorbent tubes e2 e3 systems If the contamination is shown from the experiments described above not to be coming from the carrier gas or the sorbent in the traps the next most likely candidate is the sorbent in the tubes e2 e3 systems Sorbent tubes should be thoroughly conditioned prior to use Ideally and QUI 1016 V2 2 Aug 06 116 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International certainly before use for the first time this should be done off line to avoid contaminating the TT24 7 flow path This can be done using a tube conditioner such as the TC 20 from Markes International Sorbent tubes should be conditioned at temperatures approximately 20 40 C higher than those used for desorption of the samples assuming that this does not exceed the sorbent maximum temperature See Appendix 3 for information regarding sorbent conditioning maximum sorbent temperatures etc 4 2 4 Other potential sources of contamination Unsilanized glass or quartz wool should be used as standard in the cold traps and should be conditioned at high temperatures before use Silanized glass wool can be used but is only recommended for the analysis of labile compounds Note NEVER heat silanized glass wool above 250 C even during system conditioning as the silylating reagent will break down and may irreversibly contaminate your sample flow path 4 3 Poor p
99. mon parts e1 e2 and e3 systems me p SERUTD 1125 Autosystem clamp 1 poe ES Kit TT24 7 consisting of 2 x 7 s x 12 wrench 1 x posidriver No 2 2 x 7 mm x 8 mm wrench 3 i Nut t 16 St st Swagelok Washer x 1 Pk 10 Size 007 O Ring Union brass s x 1 Pk 10 Ferrule s x 4 16 Tube PEEK OD x 0 03 bore Pk 10 Ferrule s x 2 mm Graph Vesp ffeil fle EEEEE u gt W EE QUI 1016 V2 2 Aug 06 120 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Packing Lists GC Cable Options Your TT24 7 system comes with one of the following cable options SERUTD 5098 PCB GC Interface for Agilent 6890 6850 GC or SERUTD 5095 PCB GC Interface general purpose or TGK 6000 Thermo GC Installation Kit including SERUTD 5108 PCB GC Interface for Thermo GC SERTTD 1109 Transfer line termination x1 SERZ 0119 Brass union t 16 t 16 x1 SERZ 0401 Plug cap 16 x1 U COV08 Pk 10 Size 008 O Ring X 10 SERUTD 1036 8 mm Retaining ring x2 Packing Lists e1 system specific parts Description Ce Rurale T247 User Manual Installation report back form Transfer line 1 Mains cable 1 1 1 i s p Ran be pce wh sorbent ceria QUI 1016 V2 2 Aug 06 121 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes Internationa
100. mp Pump Sample in 5 down Line from GC Trap B Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flaw gt _ Flow of Sample Gas Sample Gas no flow Figure 14 TT24 7 flow schematic e3 configuration showing the additional gas lines associated with the GC EPC module QUI 1016 V2 2 Aug 06 29 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International The pressure sensing Septum Purge line connecting to the TT24 7 may have carrier gas flowing In some GC systems this is variable If maximum sensitivity is required then this flow should be stopped or a small sample splitting will occur This can be achieved by either switching the flow off within the instrument or software or simply blanking the exit line with a closed Swagelok nut 2 4 6 2 Connection to Agilent Technologies 6890GC 6850 GC For correct operation of the Agilent Technologies EPC system with the TT24 7 a 6890 GC currently requires firmware revision of A 03 08 or N 04 09 For the 6850 GC serial numbers upwards of US10243001 will be able to provide the same functionality as the 6890 but may require a flashable firmware upgrade Note You should confirm these firmware requirements with your local Agilent Technologies representative The Injection Port Mode of the EPC module now has to be configured Using either the GC keyboard or hand held contr
101. must be taken when removing these traps from the system 2 4 4 Heated transfer line The analysis and detection of desorbed analytes from the cold traps is achieved using conventional analytical instrumentation This includes GC GCMS and in QUI 1016 V2 2 Aug 06 25 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International certain instances direct MS technology For speciation of components gas chromatography is the preferred choice using capillary columns for maximum separation efficiency Typically columns with an internal diameter of 0 32 mm or 0 25 mm are used with lengths ranging from 10 m to 60 m All standard stationary phases are suitable For splitless injection carrier flow rates equal to or greater than 3 mL min are recommended for efficient transportation of analytes from the sorbent bed into the column In split mode sampling the flow rate is by definition considerably greater than this anyway Interfacing the TT24 7 to the GC capillary column can be achieved by a number of mechanisms The most common approach uses a length of uncoated deactivated fused silica transfer line which connects and seals into the TT24 7 using a icth Swagelok nut and a 0 4 mm id graphitised vespel ferrule Installation of the transfer line is discussed in more detail in section 3 3 The transfer line is surrounded by a length of PTFE sleeving of slightly greater inter
102. n 2 3 1 The first two runs of the continuous sampling mode i e trap A and trap B would typically not be used for quantitative analysis of the sampled air but as a clean up process for both traps After both traps have been fired once then the subsequent samples may be quantified QUI 1016 V2 2 Aug 06 36 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 TT24 7e2 hardware configuration TT24 7e2 may be operated in both sampling modes continuous sampling and tube desorb 2 5 2 1 Continuous sampling mode TT24 7e2 2 5 2 1 1 Standby Desorption Tube MFC amp Pump Sample in KEY Flow of Carrier Gas Carrier Gas no flaw a Flow of Sample Gas Sample Gas no flow Figure 20 TT24 7e2 Continuous sampling standby In this non sampling mode carrier gas alone is continuously supplied to the capillary column No other gas flow occurs within the TT24 7 unit during this time QUI 1016 V2 2 Aug 06 37 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 1 2 Trap A sampling trap B purging Desorption Tube q Needle I valve KEY gt Flow of Carrier Gas Carrier Gas no flaw Flow of Sample Gas Sample Gas no flow Figure 21 TT24 7e2 Continuous sampling trap A sampling trap B purging
103. n excess of 0 5 minutes are typically used This value must be long enough to ensure complete removal of analytes from the trap into the analytical column Consideration of the trap flow conditions at trap fire are required i e the flow through the trap at trap fire is equal to the column flow rate which could be as little as 3mL min In this case a time value less than 1 minute is not recommended Incorrect setting of this time can be the cause of poor sensitivity for certain compounds as insufficient time will reduce the amount of sample leaving the trap 2 9 1 1 9 Save Once a method parameter has been changed then the word modified appears alongside the method name in the blue bar at the top of the method window When the desired method parameters have been specified they can be saved directly into the active method by clicking on the SAVE button at the bottom of the user interface 2 9 1 2 Flow display The flow display window figure 49 is designed to help the user see the flow direction process and the current run status of the TT24 7 system The diagram shows the flow direction through the solenoid valves SV1 2 3 and 4 and the flow direction through the heated valves and traps Flow Display To Column Figure 49 Flow display showing flow direction through solenoid valves 2 9 1 3 Instrument status bar Instrument Status Heated Zones GC Flow Controller Trap State 0 0 0 2 25 0 C State Not Ready Flow Rate
104. n is particularly thick it may be necessary to shorten the silicone foam rubber insulation sleeve which is intended to rest against the outer wall of the GC oven The M6 spacer nut attached to a 4 inch spacer tube on the transfer line secures the line casing to the oven wall allowing the s inch aluminium sleeve to protrude into the oven If the hole in the inner oven wall is larger than the end of the line fit one of the large metal washers from the shipping kit at this point In figure 73 the entry to the GC oven is through the fan protection grill In this situation the 4 inch spacer tube attached to the transfer line prior to the spacer nut is used to extend the line and a special U shaped metal support bracket is pushed through adjacent holes in the grill to press against the oven inner wall Note The line must not be secured with a nut against the fan grill as this could be distorted causing it to hit the fan QUI 1016 V2 2 Aug 06 99 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International me U shaped metal Spacer nut M6 Silicone foam support bracket E ma rubber insulati Aluminium heat conductor Fan protection Spacer tube grill Figure 73 Installation of transfer line through fan protection grill Figure 74 shows installation via a heated zone block As the entry hole will generally be larger than the diameter of the metal line sle
105. n molecular sieve principle permanent gases and light hydrocarbons C3 C3 Boiling point 60 C to 80 C Ultra volatile hydrocarbons E enquiries markes com TT24 7 User Manual Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes 14 Molecular Sieve 5A Sorbent Strength Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes 15 Molecular Sieve 13X Sorbent Strength Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes QUI 1016 V2 2 Aug 06 Markes International Ltd T 44 0 1443 230935 Markes International gt 400 C 350 C 400 C 300 C 350 C Significantly hydrophilic do not use in humid conditions High artefacts gt 10 ng Easily amp irreversibly contaminated by higher boiling components Very strong for small molecules Boiling point 60 C to 80 C nitrous oxide 350 C 400 C 300 C 350 C max increase temperature gradually from 100 C To suit analyte Significantly hydrophilic do not use in humid conditions High artefacts gt 10 ng Easily amp irreversibly contaminated by higher boiling components Very strong for small molecules Boiling point 60 C to 80 C 1
106. nal diameter than the outer diameter of the fused silica The PTFE is used to assist in the insertion and feeding of this length of tubing through the outer heated jacket of the transfer line It also maintains a constant temperature profile down the length of the fused silica preventing hot spots The outer layer of the transfer line is insulation material which is used to maintain a consistent and controllable temperature along its 1 2 m length figure 12 The transfer line is maintained at the same temperature as the heated valves i e the valve temperature controls the transfer line temperature setting This is typically up to 200 C Connection to the capillary column within the GC oven requires a suitable hole in the GC covers to allow the outer insulation of the transfer line to pass as far as possible to the surface of the oven without assimilating heat from the oven For certain GC systems the split splitless injection port is used as a conduit after the internal liner etc is removed The capillary column can then be connected to the transfer line using deactivated glass unions or deactivated steel connectors and ferrules Figure 12 Transfer line connection between TT24 7 and GC system As an alternative to the fused silica transfer line approach certain capillary QUI 1016 V2 2 Aug 06 26 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International co
107. national Appendix 3 Sorbent specifications 1 Carbotrap C 20 40 mesh Carbopack C 60 80 mesh Carbograph 2TD range of mesh sizes Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes Very weak 12 n Cg to n Cz9 Alkyl benzenes hydrocarbons to n C39 gt 400 C 350 C to 400 C 300 C to 350 C Hydrophobic Minimal lt 0 1 ng artefacts Some activity with labile compounds Friable 2 Tenax TA or GR range of mesh sizes Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes QUI 1016 V2 2 Aug 06 Markes International Ltd T 44 0 1443 230935 128 F 44 0 1443 231531 Weak 35 n C7 to n C39 Bpt 100 C to 450 C Aromatics except benzene apolar components bpt gt 100 C polar components bpt gt 150 C PAHs PCBs 350 C 325 C Up to 300 C Hydrophobic Low inherent artefacts lt ing Inert suitable for labile compounds Graphitised form best for PAHs PCBs Efficient desorption Use 35 60 mesh to minimise fines and eliminate leakage through conventional sorbent retaining gauzes E enquiries markes com TT24 7 Use
108. nder normal circumstances the default baud rate values of 57600 should be used However if there are communications problems then a lower baud rate be specified i e 38400 QUI 1016 V2 2 Aug 06 88 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International GC Interface logic This section of the software affects the start stop interaction between the TT24 7 and the host GC GCMSD system The actual configuration is dependent on the model of GC GCMSD used For Agilent Technologies and Thermo Electron instrumentation the GC Start out and GC Ready in settings should be in the closed state For other GC manufacturers please contact Markes International for details 2 9 2 5 3 System Gas Ports System E Mail Display Flow JV Enable Enabling this option will display the current flow rate from the MFC in the status bar Enable m Limit Sample Time Enabling this option will force the instrument to take a sample only for the specified sampling time No more gas will be sampled until the next sampling cycle M Sampling Extended Timeout Time to extend sampling IV Enable Timeout Valves IV Enable Split option for method V Purge Valve S 6 No Back Valve Figure 64 Options dialogue box system tab Display flow Limit Sample Time If the enabling box is checked the mass f
109. njection mode TT24 7 if the column flow rate is 3mL min and the septum purge approximately 3 mL min then the Total Flow will show as approximately 6 mL minute on the 6890 keyboard In split sampling mode TT24 7 if the split flow is for example 50 mL min then the Total Flow reading will appear as approximately 56 mL min This value can be seen to provide an additional electronic readout of the split flow used by the TT24 7 at trap fire QUI 1016 V2 2 Aug 06 30 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 4 6 3 Connection to Thermo Electron Trace FOCUS GC For correct operation of the Thermo Electron DPFC system with the TT24 7 the GC requires an available inlet configured for back pressure regulation The injection port mode of the DPFC module to be used has to be configured for split operation but the split flow has to be set to zero off The DPFC module is physically connected to the TT24 7 using the gas lines on the GC that are used for supplying the split splitless inlet The carrier supply and septum purge lines should be cut and extended using the s inch unions and green PEEK tubing supplied in the TT24 7 shipping kit so that they can be connected onto the back panel of the TT24 7 The carrier supply line should be connected to the carrier inlet of the TT24 7 while the septum purge line should be connected to the pres
110. nternational 2 5 3 2 3 Leak testing trap A MFC amp Pump Sample in Trap B Needle Valve h off Split Vent KEY m Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow gt _ Flow of Sarnple Gas Sample Gas no flow Figure 39 TT24 7e3 Tube desorb mode leak testing trap A After the tube leak test the selected trap also undergoes a further leak test In the example above trap A is to be used The heated valve HVC now switches to allow pressurisation via SV5 of the line right through trap A SV1 being switched OFF Once again the pressure sensor next to SV5 is monitored for pressure decay The split line pneumatics through to SV7 are also included within this leak test QUI 1016 V2 2 Aug 06 56 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 3 2 4 Tube purge MFC amp Pump Trap B Needle Valve gt Flow of Carrier Gas C Optional Carrier Gas Flow Carrier Gas no flow Flow of Sample Gas Sample Gas no flow Figure 40 TT24 7e3 Tube desorb mode tube purge Prior to the tube desorption heating phase the air and moisture which will be present in the tube needs to be flushed out to preserve the integrity of the sorbent material Carrier gas purges through the tube for a default time of 30 seconds at the tube desorb flow rate and residual air moistu
111. nual Markes International Diagnostics Pneumatics r Manual Valve Control stan ou HVA To Column Figure 65 Flow diagnostics screen 2 9 2 7 Reporting module The reporting module figure 66 displays a number of different Information Warning or Error messages All messages detailed below will appear for either Trap A or Trap B if relevant Trap Ais used as an example below All error messages are date and time stamped e g 05 12 2005 10 34 54 Reports 05 12 2005 10 49 31 INFO Samping Started on Trap A Figure 66 Reporting module 2 9 2 7 1 Information messages INFO Sampling started on Trap A date and time stamped when sampling started INFO Sampling has been extended on Trap A reported when samping time exceeded the expected time set in the method this is typically due to the GC Ready signal being delayed perhaps due to the oven taking longer than expected to cool down Information messages do not affect the operation of the system in any way QUI 1016 V2 2 Aug 06 91 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 2 7 2 Warning messages WARNING Sampling volume outside of expected range this warning message is given when the total volume sampled is not what would be expected from the method For example this could be because the sampling time was extended see section 2 9 1 5 3 or
112. ol ethanol acetone E enquiries markes com TT24 7 User Manual Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes 12 Carbosieve SIII 60 80 mesh Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes Markes International gt 400 C 350 C to 400 C 300 C to 350 C Some hydrophillicity Low artefacts lt 0 1 ng Inert suitable for labile compounds Excellent batch to batch reproducibility Non friable Easily contaminated by higher boiling components protect with front bed of weaker sorbent only Very Strong 800 but primarily operates on molecular sieve principle Ethane to n Cs5 Boiling point 60 C to 80 C Ultra volatile hydrocarbons gt 400 C 350 C to 400 C 300 C to 350 C Some hydrophillicity Low artefacts lt 0 1 ng Easily and irreversibly contaminated by higher boiling components protect with front bed of weaker sorbent 13 Carboxen 1000 range of mesh sizes Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes QUI 1016 V2 2 Aug 06 Markes International Ltd T 44 0 1443 230935 133 F 44 0 1443 231531 Very Strong for small molecules gt 1200 also operates o
113. oller 6850GC or Chemstation software access the injection port mode This consists of Split Splitless Pulsed Split or Pulsed Splitless Select the Splitless mode of injection and set the purge time to 999 99 minutes exactly This is required to prevent the EPC module resetting itself at the completion of each run which is not required with the TD system Note This exact time value is very important for EPC control of the TT24 7 The EPC module is physically connected to the TT24 7 using either the original gas lines which must be cut connecting to the split splitless inlet or preferably by using a separate pair of gas lines connecting into their own manifold Agilent Part Number G2131 80500 which replaces the original three gas line manifold This type of connection enables the original split splitless inlet to be reconfigured very easily if required If the capillary injection port is not required then it can also provide an easy access route for the heated transfer line to enter the GC oven for both the 6890 and 6850 models See section 3 3 1 for further details When using the 6890 GC the total flow of carrier gas entering the TT24 7 can be observed from the keyboard by selecting the appropriate inlet i e front or rear and scrolling down to the line Total Flow The Total Flow consists of column flow septum purge flow if applicable and the split flow within the TT24 7 For example in splitless i
114. ompletion of the download process the top LED will turn from amber to green Step 3 If however the sampler board is still not detected it may be due to an incorrect COM port designation and eventually download activity within the software will time out A dialogue box will then appear as shown in figure 46 Select Option Unable to connect to the instrument please select and option from the list below Edit Options Continue Running Figure 46 Download activity timeout dialogue box From this dialogue box select the Edit Options configuration this will launch the instrument options software page and from this selection of the Ports tab enables the COM port settings to be reviewed figure 47 Ensure that the correct COM port settings are specified See section 2 9 1 5 2 for further details QUI 1016 V2 2 Aug 06 63 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Parts System E Mail r Communications Port Analyser Port COMI z MFC Port coms 7 Baud Rate 57600 7 Baud Rate 57600 7 m GC Interface Logic GCStart out _ GC Ready in Open Start Open Ready C Closed Start C Closed Ready Cancel Figure 47 Ports tab in options configuration With the correct COM port settings specified return to Step 1 above and repeat the
115. oned sorbent tube and used to re collect the split portion of the sample for method data validation and repeat analysis SecureTD Q For further information regarding SecurelTD Q and sample re collection please see the Markes International brochure Validation of Thermal Desorption featuring SecureTD Q Quantitative sample re collection for thermal desorption Figure 90 TT24 7e2 e3 system with Split tube option on RHS To access the split tube the sealing mechanism lever should be lifted and the tube inserted removed exactly as described for the sample tube above 4 0 Troubleshooting 4 1 Leak testing the system In any gas flow path leaks may occur due to worn or ill fitting o rings fittings etc The TT24 7 flow path can be leak tested using the flow only diagnostics facility see section 2 9 1 6 2 9 2 6 In order to leak test successfully a leak detection system such as a helium leak detector Markes p n C HEL23 C HEL11 should be used QUI 1016 V2 2 Aug 06 114 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Note wet methods of leak testing e g with bubble solution SNOOP etc should be avoided at all costs Using diagnostics individual valves may be switched in order to isolate different parts of the flow path and the helium leak detector applied to the appropriate connection point to ascertain if there is a ga
116. orage temperatures N B There are other implications associated with storing tubes under refrigerated conditions Many laboratory fridge freezer atmospheres are highly contaminated with volatiles from other samples or from the refrigeration system itself N B If the tubes are to be transported in such a way as to be exposed to very cold temperature i e in an aircraft hold by rail road overnight during cold weather it is advisable to follow the above retightening procedure by cooling the tubes by placing outside or in a clean refrigerator prior to shipment When monitoring trace level atmospheric components conditioned and sampled tubes can be wrapped in uncoated aluminium foil and or placed in a sealed non outgassing container such as an uncoated tin during transportation and storage For further information on minimising artifacts see TDTS19 Trademarks and Registered Trademarks UNITY UttRA TT24 7 are all trademarks of Markes International Ltd UK Carbotrap C Carbopack C Carbotrap Carbopack B Carbotrap X Carbopack X Carbosieve SIII Carboxen 1000 are registered trademarks of Supelco Inc USA Chromosorb 102 Chromosorb 106 are registered trademarks of Manville Corporation USA Carbograph 1TD Carbograph 2TD Carbograph 5TD are registered trademarks of LARA s r l Italy GCB1 is a registered trademark of SKC Inc USA Porapak N Porapak Q are registered trademarks of Waters Associates Inc USA
117. ound contamination which is obtained If the contamination increases with the length of time that the instrument is in standby then the carrier gas supply is likely to be contaminated and individual components of the supply system should be checked If the contamination is of more volatile components then you will need to sample your carrier gas via the TT24 7 system itself using the following procedure Disconnect the carrier gas supply from the rear of the TT24 7 and attach a clean T piece and short length of tubing so that the carrier gas can now be attached to both the rear of the TT24 7 and to the sample inlet of the TT24 7 Set up a continuous sampling run on the TT24 7 to sample the carrier gas QUI 1016 V2 2 Aug 06 115 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International for a specified time period e g 10 minutes Note the background contamination which is obtained Repeat the above procedure but this time double the time period that the system is left in standby e g 20 minutes Note the background contamination which is obtained If the contamination increases with the length of time that the instrument is in standby then the carrier gas supply is likely to be contaminated and individual components of the supply system should be checked To reduce the possibility of carrier gas contamination ideally each TT24 7 system should have i
118. ow pressurisation via SV5 of the line right through trap A SV1 being switched OFF Once again the pressure sensor next to SV5 is monitored for pressure decay QUI 1016 V2 2 Aug 06 44 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 2 4 Tube purge Desorption Tube MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no flaw Flow of Sample Gas Sample Gas no flow Figure 28 TT24 7e2 Tube desorb mode tube purge Prior to the tube desorption heating phase the air and moisture which will be present in the tube needs to be flushed out to preserve the integrity of the sorbent material Carrier gas purges through the tube for a default time of 30 seconds at the tube desorb flow rate and residual air moisture is then flushed onto the chosen trap The majority of the air will pass directly through the trap as it is unretained however the trap is also dry purged in the next phase section 2 5 2 2 6 to remove any residual air and depending on the sorbent phase moisture as well QUI 1016 V2 2 Aug 06 45 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 2 5 Tube desorption Desorption Tube MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no fl
119. p State Leak testing the Tube Trap A 0 0 25 0 C Tube Oven 0 0 250 0 C State Not Ready Flow Rate 07 500 ml min TrapB State Not in use Trap B 0 0 7 25 0 C Rear HV 0 0 7 120 0 C Sample Gas Air Running Time 0 1 min Transfer Line 0 0 120 0 C Carrier Gas He Desorb Pressure 0 0 psi Dual Front HY 0 0 120 0 C Figure 60 Instrument status bar e2 e3 configurations The instrument status bar figure 60 is located at the bottom of the top level screen It is divided into four sections i e Instrument Status Heated zones GC and Flow Controller QUI 1016 V2 2 Aug 06 83 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 2 3 1 Instrument Status This shows the status of the sampling run which is operating Instrument status Indicates the current status of traps A and B e g sampling desorbing leak testing tube etc Sample Time TT Sampling mode How long the current trap has been sampling for Running Time Tube Desorb mode The run time associated with the current operational phase i e desorbing the tube leak test dry purge etc Desorb Pressure Tube Desorb mode Equivalent to the column head pressure at the point of tube desorption 2 9 2 3 2 Heated Zones This section shows the heated zones monitored within the TT24 7 Trap A Trap B Transfer Line Dual Front HV Tube Oven Rear HV The status bar shows two a
120. p compounds off the trap in the reverse direction to sampling at the point of trap fire This allows the use of traps containing more than one sorbent bed in order of adsorption strength thereby covering a much broader range of analyte that can be analysed This process can be entirely splitless for maximum sensitivity or if the split option is available configuration TT24 7e3 the sample will be split at this point See sections 2 5 1 and 2 5 2 1 to review the flow schematics for continuous sampling To assist in understanding the sequence of events occurring during continuous QUI 1016 V2 2 Aug 06 17 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International sampling and how this relates to the GC oven cycle figure 3 represents diagrammatically the operational status of both traps A and B relative to the GC cycle An arbitrary sampling time of 5 minutes is shown DP Pre Dry Purge TF Trap fire TC Trap cooling CD GC oven cool down R Ready awaiting sampling TD awaiting start run GC Figure 3 Schematic representation of TT24 7 sequence in continuous operation When the TT24 7 starts trap A immediately goes into sampling mode whereas trap B goes through a purge trap fire and trap cool sequence of events this also instigates the first GC oven cycle This maybe considered as a first run effect for both traps trap
121. p B within the trap housing Each trap is inserted through a ceramic heater sleeve and at the point of trap fire heats at rates approaching 100 C second This extremely fast heating rate removes the retained analytes from the sorbent bed s very efficiently which allows the traps to operate in splitless mode for maximum sensitivity Each trap is positioned directly on to its own Peltier cooling element This electro thermo cooling enables each trap to cool to sub ambient temperatures during the QUI 1016 V2 2 Aug 06 24 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International sampling phase which greatly enhances the trapping efficiency of the sorbent material The lower temperature is a function of the sample temperature valve temperature and sampling flow rate Dry air nitrogen or helium is used to purge the trap box to prevent the build up of moisture and the potential for icing which would effect the temperature measurement of the traps The narrow bore traps are made of quartz are restricted at the inlet outlet end and have a quartz collar on the unrestricted end figure 11 They may be packed with up to 60 mm of sorbent s which are separated and retained by quartz wool Sample enters the trap through the restricted inlet end and at the point of trap fire the trap is backflushed carrier gas flow reversed and the analytes are desorbed back out of the
122. peak splitting or discrimination as seen on conventional GC injectors In these cases reduce the amount of water or solvent retained by the cold trap e g by raising the cold trap temperature or by using a longer pre purge time If the GC analytical column is overloaded this will cause band broadening High resolution capillary columns work at optimum with analyte masses in the order of 20 200 ng QUI 1016 V2 2 Aug 06 117 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 4 4 Carryover of components of interest Carryover is usually caused by incomplete desorption and is usually addressed either by using more stringent desorption conditions higher trap desorption temperature where possible or longer trap hold time or by selecting a weaker sorbent for collecting the samples The gas flow rate is also critical and should be at least 3 mL min If the sorbent in the trap is over heated in error this may have caused high boiling materials to deposit in the internal flow path of the TT24 7 Note If you exceed the maximum sorbent temperature the resulting breakdown of the sorbent may severely contaminate the flow path of your system This may require the complete replacement of the flow path and associated components by a fully qualified service engineer and would not be covered by the instrument warranty 4 5 Poor recovery loss of sample Recove
123. pecified for correct calibrated control which is based on its density See section 2 9 2 5 1 for further information The carrier gas should be chosen for optimum performance of the associated chromatographic system and this is typically helium although other choices are available e g nitrogen and hydrogen The carrier gas flowing through the system performs several functions including dry purging the traps prior to trap fire back flushing the traps at trap fire transporting sample from the tube accessory or capillary inlet into the selected trap etc If split sampling is configured then this also places demands on the supply of carrier gas Without electronic pneumatic control this would affect the column head pressure resulting in large differences in the retention time of eluting compounds run to run Section 2 5 shows the schematics illustrating the flow protocol within the TT24 7 for each sampling mode within each hardware configuration The carrier gas supply entering the TT24 7 originates from the associated GC system and in particular from the electronic flow module normally supplying gas to a split splitless injection port This gas supply is now redirected from the capillary inlet into the TT24 7 An important aspect associated with the control of the carrier gas is called closed loop feedback This relates to controlling the capillary column head pressure so that whatever flow demands are made by the various processes occurring
124. process Step 4 The next step is downloading firmware into the mass flow controller board MFC which is represented by the lower LED To achieve this turn the front panel switch On depressed at which point the lower LED turns red The software will automatically attempt to download the firmware into the MFC board and this is indicated by the LED turning amber As for the sampler board if detection of the MFC board is unsuccessful toggle the front panel switch off wait 10 seconds and on and the software will re attempt to download the firmware again On successful completion the lower LED will turn green If the download is still unsuccessful then check the COM settings for the MFC board as specified in Step 3 above At this point both LEDs should appear green and the user interface should be loaded onto the PC display 2 9 Software control top level The top level software screen is shown in figure 44 above Four separate windows are shown titled Method Flow Display and Reports and at the base of the screen the Instrument Status display Above the screen are seven graphical icons and a menu bar The software control and user interface will vary according to the hardware configuration installed Ensure that you know which configuration you have prior to reading this manual see Introduction QUI 1016 V2 2 Aug 06 64 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24
125. r Manual Markes International 3 Carbotrap 20 40 mesh Carbopack B 60 80 mesh GCBi range of mesh sizes Carbograph i1TD range of mesh sizes Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes Medium Weak 100 n Cs7 6 to n Cy4 Ketones alcohols aldehydes and apolar components within the above volatility range Perfluorocarbon tracer gases gt 400 C 350 C to 400 C 300 C to 350 C Hydrophobic Low artefacts lt 0 1 ng Some activity with labile compounds Friable 4 Carbopack X 40 60 and 60 80 mesh Carbotrap X 20 40 mesh Sorbent Strength Specific Surface Area m2 g Approximate analyte volatility range Example Analytes Sorbent Maximum Temperature Recommended Conditioning Temperature Recommended Desorption Temperature Notes QUI 1016 V2 2 Aug 06 129 Markes International Ltd T 44 0 1443 230935 Medium Strong 240 n C374 to n C6 7 Boiling point 50 C to 150 C Light hydrocarbons BTX for 2 week diffusive exposure gt 400 C 350 C to 400 C 350 C to 400 C Hydrophobic Low artefacts lt 0 1 ng Some activity with labile compounds Friable F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 5 Carbograph 5TD various mesh sizes
126. r achieved using gas filters Typically QUI 1016 V2 2 Aug 06 97 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International this will include a Moisture trap P N C MSTRP Oxygen trap P N C O2TRP and Hydrocarbon trap P N C HCTRP The external supply pressure of carrier gas needs to be 10 psi greater than the capillary column head pressure requirements If the column is operating in constant pressure mode this is a simple addition i e for a head pressure of 30 psi the supply pressure needs to be 40 psi etc However if constant flow conditions are being used then the supply pressure needs to be calculated at the oven maximum value when the pressure demand by the column is at its greatest Connection of the carrier gas to the TT24 7 is discussed in section 2 4 6 1 The trap box purge and valve actuator gas is typically dry air nitrogen or carrier gas He only This needs to be supplied at a pressure between 50 and 70 psi and must have a dew point lower than 35 C The trap box purge gas is essential to prevent moisture condensation and subsequent icing within the Peltier cooled trap box If this occurs the lower i e sub ambient temperatures will not be achievable The dry gas supply must always be on when the 1TT24 7 is being used and secondary pressure regulation of this gas supply is required in addition to the laboratory control Markes Internat
127. r purging the trap B for the first time trap fire occurs and flow is directed backflushed across to the capillary column This first B trap fire prepares the trap for subsequent sampling The flow rate through the trap is equal to the column flow rate and should be at least 3 mL min QUI 1016 V2 2 Aug 06 39 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 1 4 Trap A purging trap B sampling Desorption Tube q Needle N valve MFC amp Pump Trap B KEY Flow of Carrier Gas Carrier Gas no flaw Flow of Sample Gas Sample Gas no flow Figure 23 TT24 7e2 Continuous sampling trap A purging trap B sampling After the sampling time for trap A has completed trap A switches into its dry purge mode to sweep out air and moisture prior to trap fire Having cooled to its starting temperature after the first clean up trap fire trap B now goes into its sampling phase The date and time that the sampling started and the trap that is being sampled are reported as an information message in the reporting module of the software see section 2 9 2 7 e g 05 12 2005 10 49 31 INFO Sampling Started on Trap B QUI 1016 V2 2 Aug 06 40 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 1 5 Trap A desorbing trap B sampling
128. re is then flushed onto the chosen trap The majority of the air will pass directly through the trap as it is unretained however the trap is also dry purged in the next phase section 2 5 3 2 6 to remove any residual air and depending on the sorbent phase moisture as well QUI 1016 V2 2 Aug 06 57 TT24 7 User Manual Markes International 2 5 3 2 5 Tube desorption Desorption Tube MFC amp Pump Sample in Trap B Needle Valve 5s off Split Vent KEY m Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow Flow of Sample Gas Sample Gas no flow Figure 41 TT24 7e3 Tube desorb mode tube desorption The tube is now heated to the temperature set as the Desorb Temp within the TT24 7 method The tube Desorb Flow and Desorb Time parameters control the desorption process The set Desorb Temp value will depend on the sorbent material and should not be set higher than that recommended for the sorbent s in the tube See Appendix 3 for further details on sorbent selection and maximum recommended temperatures Sufficient flow and time should be maintained to completely desorb all analytes from the tube onto the specified trap A or B In the schematic above A is the chosen trap QUI 1016 V2 2 Aug 06 58 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 3 2 6 Trap A purge
129. ry of labile components may often be improved by increasing the trap hold time and column gas flow rate while reducing the desorption and flow path temperatures Many volatile labile analytes will pass successfully through TT24 7 with flow path temperatures as low as 50 C For the analysis of extremely labile relatively involatile components bp gt n C12 silanized glass or quartz wool alone should be used as the cold trap packing material where possible If a multibed cold trap is being used ensure that the different sorbents are kept in discrete beds separated by unsilanised glass wool quartz wool plugs and arranged in order of increasing sorbent strength i e weak to strong from the sampling QUI 1016 V2 2 Aug 06 118 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Appendix 1 Packing List and Routine Maintenance Spares The following items are included with your TT24 7 system please check carefully and inform your distributor if there are any shortages Items marked with a are consumable items and may require changing at regular intervals the commercial re order number is given in the description and detailed in the routine maintenance spares section QUI 1016 V2 2 Aug 06 119 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Packing List com
130. s Sample Gas no flow Figure 36 TT24 7e3 Continuous sampling trap A desorbing trap B sampling Trap A now fires If this is the first run for A this run is treated as a clean up run however if this is a subsequent run then real sample will be transferred across to the capillary column for analysis If the split function is enabled in the method see section 2 9 2 1 14 then this will occur at trap fire Trap A Desorbing The flow rate through the trap is therefore equal to the column flow plus the split flow through SV7 The split ratio is therefore Split Ratio Column Flow Column flow Split flow If the split function is not enabled then the flow rate through the trap is equal to the column flow rate alone and should be at least 3 mL min To see how the time overlap of sampling dry purging trap fire and cooling occurs relative to the GC oven cycle time please refer to section 2 3 1 QUI 1016 V2 2 Aug 06 53 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 3 2 Tube desorb mode TT24 7e3 2 5 3 2 1 Standby Desorption Tube MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow gt _ Flow of Sample Gas Sample Gas no flow Figure 37 TT24 7e3 Tube desorb mode standby In this non sampling mode carrier gas alone is continuously supp
131. s being sampled are reported as an information message in the reporting module of the software see section 2 9 1 7 e g 05 12 2005 10 49 31 INFO Sampling Started on Trap A The sample passes initially onto trap A while trap B pre purges with carrier gas in the desorption direction This removes air and moisture from the trap prior to firing The pre purge flow is determined by the column flow and should be at least 3 mL min The sample gas flow rate passing into the TT24 7 is controlled by the internal mass flow controller MFC QUI 1016 V2 2 Aug 06 33 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 1 3 Trap A sampling trap B desorbing MFC amp Pump Trap B KEY Flow of Carrier Gas Carrier Gas no flaw gt _ Flow of Sample Gas Sample Gas no flow Figure 17 TT24 7e1 Trap A sampling trap B desorbing After purging the trap B for the first time trap fire occurs and flow is directed backflushed across to the capillary column This first B trap fire prepares the trap for subsequent sampling The flow rate through the trap is equal to the column flow rate and should be at least 3 mL min QUI 1016 V2 2 Aug 06 34 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 1 4 Trap A purging trap B sampling M
132. s either from the tube or using the continuous sampling mode The tube desorption configuration can also be used for real tube sampling In certain applications a confirmatory tube is positioned within an environment to back up a continuous monitoring station The sampling process could be pumped or diffusive If the continuous system alarms then tubes could be analysed on the TT24 7 to confirm this response 2 3 3 Split sampling Available with hardware configuration e3 only The 1124 7 may be configured with the capacity to split the sample at the point of trap fire This functionality can be turned on and off in the TT24 7 software see section 2 9 When split sampling is not configured the TT24 7 will desorb sample from the trap in a splitless manner directly into the analytical capillary column For those applications where maximum sensitivity is required this is the preferred mode of sampling However there are instances where a more flexible mechanism for loading sample into the column is required In this instance the ability to split the sample at the point of trap fire is advantageous The split flow is controlled by a small needle valve on the right hand side of the TT24 7 Figure 6 shows the TT24 7 with the split accessory fitted TT24 7e3 Measurement of the split flow is achieved using a digital flow measuring device connected to this vent line QUI 1016 V2 2 Aug 06 20 Markes International Ltd T 44 0 1443 230935 F
133. s leak In addition to the flow diagnostics the TT24 7 software can perform a manual leak test of desorption tube trap A and trap B by clicking on the appropriate icon in the software see section 2 9 2 4 1 4 2 Contamination the presence of artifacts in the chromatogram Artifacts are usually the result of either insufficient conditioning of sorbent from the cold traps or sorbent tube where applicable e2 e3 systems or contamination from the carrier gas or carrier gas supply equipment 4 2 1 The carrier gas supply The carrier gas supply is a common source of contamination in thermal desorption Contaminants may derive from the gas itself cylinder head regulators gas lines or carrier gas filters If the contamination is of high boiling compounds then use the following procedure to establish whether the gas supply is at fault Immediately after a GC run cool the GC oven down to ambient temperature and leave the TT24 7 in standby for a period of time e g 10 minutes Carrier gas will now be passing directly into the GC column and because the column is at ambient temperature any high boiling contamination will be focusing on the front of the column After the selected time period start the GC run by manually pressing RUN on the GC system Note the background contamination which is obtained Repeat the experiment but this time double the time period that the system is left in standby e g 20 minutes Note the backgr
134. strument and carefully slide the pneumatics towards the traps until the trap valve connectors P N TTD 5032 have sealed onto the traps Note It is easier to locate the trap tube links on the cold traps if they are gently rotated as they are pushed onto the cold traps QUI 1016 V2 2 Aug 06 108 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International X Figure 86 TT24 7e1 with overlaid schematic showing trap positions and user serviceable parts 3 4 2 Removing the cold traps Refer to Figure 86 Ensure that the instrument is in standby Remove the trap pneumatics by loosening the locating screw and carefully sliding the pneumatics forward QUI 1016 V2 2 Aug 06 109 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Note Take care not to rotate the trap pneumatics as they are moved to avoid breaking the cold traps Once clear of the cold traps lift the trap pneumatics clear of the traps and move to the RHS of the instrument Close the TT24 7 software Switch the instrument off Collared Traps Place the trap extraction tool TTD 5032 over the cold trap so that the notch of the tool sits directly behind the cold trap collar While holding the tool in place begin to unsdrew the knob at the front of thre trap extraction tool which will extract
135. sure outlet see figure 13 If the capillary injection port is not required then it can also provide an easy access route for the heated transfer line to enter the GC oven See section 3 3 1 for details 2 4 6 4 Connection to other GC systems Electronic pneumatic control using Shimadzu GC systems is also possible The carrier gas and septum purge line are configured similarly to both the Agilent and Thermo Electron systems For more information please contact Markes International Ltd 2 5 TT24 7 flow schematics This section reviews the flow schematics for the TT24 7 for the three hardware configurations available TT24 7e1 TT24 7e2 and TT24 7e3 These will identify the direction of flow of carrier gas sampling gas and dry purge gas for two sampling modes Continuous Sampling and Tube Desorb Each section shows the chronological order of events during the thermal desorption process The solenoid valves are labelled with a numerical SV designation going from SV1 through to SV7 The status of each solenoid valve is either ON or OFF SV1 SV2 SV3 and SV4 are three way valves whose ON OFF status controls the direction of carrier gas flow SV5 SV6 and SV7 where fitted are two way ON OFF solenoids The heated PTFE valves are labelled HVA HVB and HVC where fitted Each valve is in an UP or DOWN status depending on the two pin position of each valve Total carrier gas flow into the TT24 7 is controlled by the electronic
136. system 4 2 Contamination the presence of artifacts in the chromatogram 4 2 1 The carrier gas supply 4 2 2 Contamination from the cold trap 4 2 3 Contamination from the sorbent tubes e2 e3 systems 4 2 4 Other potential sources of contamination 4 3 Poor peak shape peak splitting 4 4 Carryover of components of interest 4 5 Poor recovery loss of sample Appendix 1 Packing List and Routine Maintenance Spares Appendix 2 Dynamic Data Exchange DDE software control Appendix 3 Sorbent specifications 1 Carbotrap C 20 40 mesh Carbopack C 60 80 mesh Carbograph 2TD range of mesh sizes 2 Tenax TA or GR range of mesh sizes 3 Carbotrap 20 40 mesh Carbopack B 60 80 mesh GCBi range of mesh sizes Carbograph 1TD range of mesh sizes QUI 1016 V2 2 Aug 06 6 110 111 111 112 112 114 114 114 115 115 116 116 117 117 118 118 119 125 128 128 128 129 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Carbopack X 40 60 and 60 80 mesh Carbotrap X 20 40 mesh Carbograph 5TD various mesh sizes 4 5 6 Chromosorb 102 range of mesh sizes available 7 Porapak Q range of mesh sizes available 8 Porapak N range of mesh sizes available 9 HayeSep D range of mesh sizes available 10 Chromosorb 106 range of mesh sizes available
137. t Trap A Not Heating 1 or O lt TBH gt Trap B Not Heating 1 or O lt FVH gt Front Valve Not Heating 1 or O lt TLH gt Transfer Line Not Heating 1 or O lt TOH gt Tube Oven Not Heating 1 or O lt RVH gt Rear Valve Not Heating 1 or O lt TAT gt Trap A Over Temperature 1 or O lt TBI gt Trap B Over Temperature 1 or O lt FVT gt Front Valve Over Temperature 1 or O lt TLT gt Transfer Line Over Temperature 1 or O lt TOT gt Tube Oven Over Temperature 1 or O QUI 1016 V2 2 Aug 06 125 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International lt RVT gt Rear Valve Over Temperature 1 or O lt split gt Split Valve Open 1 or O lt flow gt Current Flow Rate lt error gt General Instrument Error occurred 1 or O Temperatures Returns A comma separated list of values in the order shown below lt TA gt The Temperature of Trap A lt TB gt The Temperature of Trap B lt TL gt The Temperature of the Transfer Line lt FV gt The Temperature of the Front Heated Valve lt RV gt The Temperature of the Rear Heated Valve lt TO gt The Temperature of the Tube Oven CurrentMethod Returns The name of the currently active method FlowRate Returns The current Flow value ActiveTrap Returns Which trap is currently active SampleTime Returns The current sample time Commands The following commands
138. t ic Tnstrument Status eated Zone GC Flow Controller TrapA State 0 rap A 0 0 25 0 TubeOven 00 2500C State Not Ready low F 07 500 mimin TrapB State 0 rap B 10 Rear HV 0 0 120 0 C e ir Sample Time 00 min i xr Figure 44 TT24 7 software top level screen QUI 1016 V2 2 Aug 06 61 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International At the top of the screen are function icons and a menu bar for instrument configuration and control 2 7 Software installation Remove the software CD from its packaging and insert into the CD drive of the PC Access the CD drive from Windows and click on the Setup icon Follow the on screen instructions to complete the installation of the software 2 8 Firmware download After the software has been loaded onto the PC the firmware has to be downloaded into two separate boards within the TT24 7 system Firstly ensure that all the electrical connections between the TT24 7 the PC and the rest of the analytical system are in place See section 3 1 for details On the front panel of the TT24 7 there are two LED display lights and an instrument activity switch The LEDs refer to the status of the Sampler and MFC boards within the TT24 7 and show different colours depending on the download status of the firmware figure 45 E HHE S352 E SESz s 2 Sampler LED MFC L
139. tems the transfer line inlet is situated behind the front two heated valves and the transfer line is installed vertically down into the union To obtain access to the installation point first remove the heated valve cover as follows Loosen the two screws holding the back panel in place figure 75 and remove the panel Back panel screws Figure 75 Loosen the back panel screws Remove the four M4 nuts at the front of the valve box and lift the box off figure 76 QUI 1016 V2 2 Aug 06 101 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Figure 76 Remove the M4 nuts Figure 77shows the ie inch stainless steel union into which the fused silica transfer has to be fitted Figure 78 shows a partly sectioned view of this 16 inch union giving an indication of where to position of the end of the fused silica tubing Figure 77 Transfer line connection QUI 1016 V2 2 Aug 06 102 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Carrier bypass Fused silica terminates ere 1 16 inch inert oated stainless steel tubing 0 5 mm bore Analytes from the trap via the heated ee Figure 78 Precise positioning of end of fused silica transfer line If the fused silica terminates in the space above the end of the inert coated stainless steel
140. ternational 2 5 2 2 7 Trap A desorption Desorption Tube Purge Vent Needle Vale MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no flaw a Flow of Sample Gas Sample Gas no flow Figure 31 TT24 7e2 Tube desorb mode trap desorption The selected trap is now rapidly heated and backflushed with carrier gas to remove retained analytes from the sorbent bed s into the capillary column The flow rate through the trap is equal to the column flow and should be at least 3 mL min QUI 1016 V2 2 Aug 06 48 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 3 TT24 7e3 hardware configuration TT24 7e3 includes the option to split sample and may be operated in both sampling modes continuous sampling and tube desorb 2 5 3 1 Continuous sampling mode TT24 7e3 2 5 3 1 1 Standby MFC amp Pump Sample in Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow Flow of Sample Gas Sample Gas no flow Figure 32 TT24 7e3 Continuous sampling standby In this non sampling mode carrier gas alone is continuously supplied to the capillary column No other gas flow occurs within the TT24 7 unit during this time QUI 1016 V2 2 Aug 06 49 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 Us
141. the cold trap from the heated valve o ring Once fully unscrewed the knob can then be pulled forward to extract the cold trap from its housing Note Cold traps are much easier to remove whilst the o rings in the heated valves are still hot Uncollared Traps Carefully pull each of the cold traps out Note Using a latex glove will provide better grip on the traps to aid removal Note Cold traps are much easier to remove whilst the o rings in the heated valves are still hot If the cold traps remain difficult to pull out then switch the instrument back on and re download the firmware allow the heated valves to attain their temperature set point switch the instrument off and repeat the process 3 4 3 Available Cold Traps A range of pre packed TT24 7 cold traps are available from Markes as follows QUI 1016 V2 2 Aug 06 110 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Pareno peseripton T 1VX TT24 7 cold trap optimised for the sampling of CW agents specifically VX T 2HD TT24 7 cold trap optimised for the sampling of CW agents specifically Mustard HD T 3GBGE TT24 7 cold trap optimised for the sampling of CW agents specifically Sarin GB and the G analogue of VX GE T 6EMP TT24 7 empty cold trap for packing by user T 7CUS 1124 7 cold trap custom packed to user specification 3 4 4 User maintenance of TT24 7 col
142. then back ON After this has occurred the firmware is automatically downloaded into the TT24 7 The desired sampling method can then be started again The recycle box has two power IN OUT supply sockets and two IN OUT serial ports The power supply to the TT24 7 now passes through the recycle box which in turn connects into the power socket of the TT24 7 The power cable connecting the recycle box to the TT24 7 has a female socket at either end P N Z 0207 The serial port connection to the Sampler socket in the TT24 7 also passes through the recycle box and it is this connection which initiates a power cycle when the software is downloaded Figure 71 shows a schematic of this configuration USB Hub USB to Serial MFC cable P N U USBSR Standard USB Cable Power Recycle Box Serial Cable Serial Cable Remote Start P N 2 0189 PIN 2 0189 Power connector P N seeccoad PC to GC Comms cable eg LAN RS232 Agilent UTD 5098 Remote Start Cable P N Thermo UTD 5108 Figure 71 Cable connections including power recycle box 3 2 Gas requirements The gases required by the TT24 7 system are Carrier Gas Sample gas continuous sampling mode Trap box purge gas and heated valve actuator pneumatics The quality of both the carrier gas and the purge gas is an important consideration For the carrier gas the quality must be 5 0 grade 99 999 or better This can be achieved directly from the supply tank o
143. tinue running t Initiates a leak test procedure The first function is to perform a leak test of the tube followed by a leak test of trap A and then trap B Allows manual needle valve control of the split flow through z SV7 if enabled e3 systems and dry purge flow through SV6 QUI 1016 V2 2 Aug 06 85 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 9 1 4 2 Menu bar File File View Instrument Hel k New Open Save Ctrl 5 Save As Ctrl Alt 5 Simple Mode Exit Ctrl x New Open Save Save As Exit View B 1124 7 Control File view Instrument b Options Diagnostics Options Creates a new method which starts with default parameters Opens the method subdirectory so that an existing method can be loaded into the TT24 7 Saves the current TT24 7 parameters directly into the loaded method Requests a method file name to be saved into the methods sub directory No suffix is required as the mth suffix is automatically added Immediately closes down the TT24 7 software Accesses the 1124 7 configuration software see section 2 9 1 5 for details Diagnostics Accesses two levels of diagnostic software for the Instrument B 1124 7 Control File View Instrument D EP Run Run Stop QUI 1016 V2 2 Aug 06 TT24 7 flow only user diagnostics and full service engin
144. tly and the TT24 7 will not function QUI 1016 V2 2 Aug 06 111 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 3 4 4 2 Cold trap lifetime Cold trap lifetime is dependent upon a number of factors the sorbent s type used in the trap porous polymers have a lower lifetime than graphitised carbon sorbents for example the maximum temperature that the trap is routinely heated to during trap fire and the length of time it is held at this temperature operating your traps close to the maximum temperature of the sorbents within them will reduce trap lifetime the nature of the compounds being analysed When the performance of the trap starts to deteriorate it is time to replace both traps In any event it is recommended that cold traps are replaced annually 3 5 Installation removal of sampling tube e2 e3 The sampling tube is located on the left hand side of the TT24 7 when looked at from the front of the instrument figure 87 Figure 87 TT24 7e2 e3 system with Desorb Tube option on LHS To access the tube oven which houses the sampling tube the sealing mechanism lever should be lifted see figure 88 QUI 1016 V2 2 Aug 06 112 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Figure 88 TT24 7e2 e3 system tube sealing mechanism lever
145. trolling PC will typically have a battery backup for a few hours When the power returns the GC will switch on and reset to its original method values however the TT24 7 requires the firmware to be downloaded again This requires the TT24 7 software to be closed as it will still be active due to the battery backup in the PC If the power failure extends beyond the battery backup of the PC then the PC software will have to be rebooted from scratch User name login and passwords will be required to access the Microsoft Windows desktop followed by rebooting of both the TT24 7 and GC software To successfully download the firmware into the TT24 7 it is recommended that the instrument is switched OFF and then ON at the back of the instrument This will turn both LED lights to red as discussed in section 2 8 The TT24 7 is now ready to receive the firmware download and this is achieved by rebooting the software as described in section 2 8 However where remote system control is active the ON OFF switch at the rear QUI 1016 V2 2 Aug 06 96 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International of the instrument cannot be physically accessed so an alternative mechanism is required This is achieved using a power recycle box P N U RCYBX The power recycle box is activated when the TT24 7 software is initiated this electronically switches the system OFF and
146. ts own independent carrier gas supply separate from any other conventional chromatographs in the laboratory Note TT24 7 is such a good concentrator of VOCs that normal laboratory gas lines which perform perfectly well for conventional GC analyses can produce artifacts on the system It is recommended that the gas itself and gas line components meet the requirements stated in section 3 2 4 2 2 Contamination from the cold trap If the contamination is shown from the experiment described above not to be coming from the carrier gas the next most likely candidate is the sorbent in the traps or sorbent tube where applicable e2 e3 systems See Appendix 3 for information regarding sorbent conditioning maximum sorbent temperatures etc To condition the traps set up a continuous sampling method with the following parameters an extended pre purge time e g 5 minutes a short sampling time e g 30 seconds a maximum trap temperature which is 10 20 C higher than that normally used for analysis assuming that this does not exceed the sorbent maximum temperature see Appendix 3 typically to extend trap lifetime your operating method should not require the trap to be used at its maximum temperature an extended trap hold time e g 5 minutes run this method through both traps you may need to run the method through each trap more than once depending on the contamination levels found 4 2 3 Contamination fro
147. ty cold trap T 7CUS TT24 7 cold trap custom packed to your specification QUI 1016 V2 2 Aug 06 124 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International Appendix 2 Dynamic Data Exchange DDE software control Dynamic data exchange DDE provides a mechanism to control and monitor the TT24 7 externally to the standard system software The section below supplies the control and status commands to achieve this DDE commands are typically embedded in macro programs within the GC GCMS host software and enable that software to take control of the TT24 7 This is usually implemented to add some custom functionality to the system An example of this would be to modify a method parameter or entire method based on an analytical result The DDE functionality is designed for customers with a strong background in software programming TT24 7 DDE Interface To create the connection to the DDE interface you will need to use the following settings Service Name Topcat Topic DDEInterface Information Requests The following information can be returned from the TT24 7 software The Request item names are case sensitive State Returns A comma separated list of values in the order shown below lt mode gt Operating Mode lt state gt Standby Running or LeakTest lt TAL gt Trap A Leak Error 1 or O lt TBL gt Trap B Leak Error 1 or O lt TAH g
148. ual Markes International 2 5 3 1 4 Trap A purging trap B sampling Desorption Tube q Needle N valve i n H He i C see O H MFC amp Pump Sample in off on Trap B TA a Split Tube KEY gt Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow Flow of Sample Gas Sample Gas no flow Figure 35 TT24 7e3 Continuous sampling trap A dry purging trap B sampling After the sampling time for trap A has completed trap A switches into its dry purge mode to sweep out air and moisture prior to trap fire Having cooled to its starting temperature after the first clean up trap fire trap B now goes into its sampling phase The date and time that the sampling started and the trap that is being sampled are reported as an information message in the reporting module of the software see section 2 9 2 7 e g 05 12 2005 10 49 31 INFO Sampling Started on Trap A Carrier gas also purges down the split line to purge any air from the line and to prevent ingress into the system QUI 1016 V2 2 Aug 06 52 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 3 1 5 Trap A desorbing trap B sampling MFC amp Pump Sample in Needle Valve off Split Tube me OOS G a i KEY gt Flow of Carrier Gas Optional Carrier Gas Flow Carrier Gas no flow gt _ Flow of Sample Ga
149. uch sharper peak and a significantly better S N ratio even though the amount of analyte trapped is half The science behind this effect is based on the depth the analyte passes into the sorbent and as a consequence how easily it comes off at trap fire It is therefore both compound and sorbent dependant 2 9 1 1 5 Sample time This specifies the time interval for sample to pass into the trap This parameter is directly associated with the sampling flow rate as discussed above to determine the total amount of sample transferred The range for sample time is from 0 1 to 99 9 minutes however values greater than 1 minute will typically be used The sampling time and therefore the sampling volume can be affected by the QUI 1016 V2 2 Aug 06 66 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International ready not ready status of the GC system At the completion of the defined set point time value and prior to the system going into the pre purge phase of the trap the TT24 7 monitors the GC ready status If the GC is ready then the pre purge process commences If however the GC is not ready then the sampling time is extended until the GC becomes ready or a specified time out value see section 2 9 1 5 3 is equalled at which point the system stops The GC becoming not ready is typically due to the oven not cooling down as fast as normal and this affects the GC
150. using Figures 4 and 5 below show the TT24 7 with the tube accessory fitted Figure 4 TT24 7e2 showing tube accessory fitted and sorbent tube ready to be sealed into position Figure 5 TT24 7e2 showing tube accessory fitted and sorbent tube sealed into flow path The flow schematics for the tube desorption process can be seen in section 2 5 2 The ability to desorb a single tube using the TT24 7 considerably extends the functionality of the system beyond that of a single mode continuous sampler QUI 1016 V2 2 Aug 06 19 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International An example of this flexibility is the capacity of the system to desorb the analytes retained within the tube onto either trap A or trap B This is a user selectable function within the TT24 7 Tube Mode sampling configuration in the software See section 2 9 This enables equivalency of trap performance to be assessed by desorbing a test sample initially into trap A and then into trap B and comparing the data This could also be used as a method validation tool to check for system bias for each trap Single tube desorption also enables calibration of the detector within the associated GC or GCMS system If a tube is spiked with a standard of known concentration and analysed then the detector can be easily calibrated This will enable quantitative analysis of subsequent sample
151. w of Carrier Gas Carrier Gas no flaw gt Flow of Sample Gas Sample Gas no flow Figure 26 TT24 7e2 Tube desorb mode leak testing tube The first stage in tube desorption is a tube leak test This is essential as the tube has been inserted into the TT24 7 flow path and sealed with two retaining o rings one at the front and back of the tube oven See section 3 5 for tube installation instructions During this phase the tube desorption flow lines in the TT24 7 are initially pressurised with carrier gas and then solenoid SV5 is switched OFF to seal the system The heated valves are configured so that there is no connection beyond HVC The pressure sensor P adjacent to SV5 is monitored to measure the rate of pressure decay If this is acceptable lt 5 drop in pressure within 30 seconds the software moves on to the next phase in the tube desorption process QUI 1016 V2 2 Aug 06 43 Markes International Ltd T 44 0 1443 230935 F 44 0 1443 231531 E enquiries markes com TT24 7 User Manual Markes International 2 5 2 2 3 Leak testing trap A MFC amp Pump Sample in Trap B KEY Flow of Carrier Gas Carrier Gas no flaw a Flow of Sample Gas Sample Gas no flow Figure 27 TT24 7e2 Tube Desorb Mode Leak testing trap A After the tube leak test the selected trap also undergoes a further leak test In the example above trap A is to be used The heated valve HVC now switches to all
152. y way 2 9 1 7 2 Warning messages WARNING Sampling volume outside of expected range this warning message is given when the total volume sampled is not what would be expected from the method For example this could be because the sampling time was extended see section 2 9 1 5 3 or because the flow controller was unable to pull the required flow rate over the sampling time due to a failing cold trap or other problem A warning message does not affect the operation of the TT24 7 system but gives information about something which may affect the quantitation and the results 2 9 1 7 3 Error messages ERROR Trap A not heating ERROR Valve not heating ERROR Line not heating ERROR Trap A over temperature ERROR Valve over temperature ERROR Line over temperature If one of the above errors occur then the TT24 7 system will shut down and await operator service engineer intervention 2 9 2 User interface for TT24 7e2 and TT24 7e3 hardware configurations 2 9 2 1 Method parameters At the top of the method window is shown the active method name e g default mth and its status i e whether or not it has been modified from its original set point values The set point values used in the interface are described below 2 9 2 1 1 Mode Hardware configurations e2 and e3 allow two different sampling modes each with a slightly different user interface Figure 58 shows the two user interfaces for the different sampling modes Q

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