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1.0 ethos 900 1.1 introduction 1.2 technical specifications

1. WARNING Never install the ETHOS 900 under a fume hood In fact if you should install the microwave system under a fume hood the acid vapors might contaminate the air used for ventilating the electronic components exposing them to a possible corrosion 1 5 1 UNPACKING AND CHECKING LIST When unpacking verify that all parts correspond to the packing list included in the shipment Utmost care must be taken during unpacking of the ETHOS 900 to avoid any scratch or damage to the special acid and organic solvent resistant external coating next picture Remove the carton box located in the upper part of the box picture and keep it apart It contains accessories which will be taken during the installation of the ETHOS 900 The carton box should include the following e n 1 Milestone ETHOS 900 microwave labstation e n 1 Power cord for ETHOS 900 e n 1 Plastic hose 2m long e n 1 Control terminal model 240 e n 1 Interface cable 5 pin for connecting the ETHOS 900 to the control terminal model 240 ETHOS 900 Page 8 Lift up the main carton box to facilitate the removal of the ETHOS 900 picture The ETHOS 900 comes protected by a plastic bag to avoid problems of wetting during its transportation Provide a bench of at least 1m length and 80cm wide and locate the ETHOS 900 on the bench A proper location of the ETHOS 900 is next to a fume hood since the microwave unit
2. TEMP 2 80 C 2 1 gt 500 ENT OK Press ENT to confirm the value the display will now show the 3 step of the program 1 TIME hh mm ss 3 1 ENT OK Introduce the desired time of the 3 step 4 minutes in our case by pressing 0 0 0 and 4 on the keyboard The display will show TIME 00 04 ss 3 1 ENT OK Press ENT to confirm the display will show POWER ow 3 1 gt 900 ENT OK It is now possible to enter the microwave power level of the 3 step 500Watt in our case Press 5 and 0 on the keyboard and the display will show Software mod lev 6 17 Page 3 POWER 1 500 W 3 1 gt 900 ENT OK Press ENT to confirm the display will show PRESSURE B 3 1 gt 100 ENT OK Press 6 on the keyboard and the display will show PRESSURE 10B 3 1 gt 100 ENT OK Press ENT to confirm the value the following message will appear TEMP 1 _ 3 1 gt 400 ENT OK Press 2 1 and 0 210 C on the keyboard and the display will show TEMP 1 210 C 3 1 gt 400 ENT OK Press ENT to confirm the value the following message will appear TEMP 2 ie 3 1 gt 500 ENT OK Press 8 and 0 80 C on the keyboard and the display will show TEMP 2 80 C 3 1 gt 500 ENT OK Press ENT to confirm the value the display will now show the 4 step of the program 1 TIME hh mm ss 4 1 ENT OK Our exam
3. to confirm the value the following message will appear TEMP 2 EG 1 1 gt 500 ENT OK Press 7 and 0 70 C on the keyboard and the display will show TEMP 2 70 C 1 1 gt 500 ENT OK Press ENT to confirm the value the display will now show the 2 step of the program 1 TIME hh mm ss 2 1 ENT OK Introduce the desired time of the 2 step 5 minutes in our case by pressing 0 0 0 and 5 on the keyboard The display will show TIME 00 05 ss 2 1 ENT OK Press ENT to confirm the display will show POWER OW 2 1 gt 900 ENT OK Software mod lev 6 17 Page 2 It is now possible to enter the microwave power level of the 2 step 400Watt in our case Press 4 and 0 on the keyboard and the display will show POWER 1 400 W 2 1 gt 900 ENT OK Press ENT to confirm the display will show PRESSURE B 2 1 gt 100 ENT OK Press 6 on the keyboard and the display will show PRESSURE 6B 2 1 gt 100 ENT OK Press ENT to confirm the value the following message will appear TEMP 1 TE 2 1 gt 400 ENT OK Press 1 8 and 0 150 C on the keyboard and the display will show TEMP 1 180 C 2 1 gt 400 ENT OK Press ENT to confirm the value the following message will appear TEMP 2 C 2 1 gt 500 ENT OK Press 8 and 0 80 C on the keyboard and the display will show
4. 1 0 ETHOS 900 1 1 INTRODUCTION In the world of microwave sample preparation Milestone continue to quietly lead the evolution of technology Our only focus is to provide you with the most technologically advanced instrumentation for total microwave sample preparation In 1994 the ETHOS project was started to develop a new generation of microwave chemistry systems based on the experience of several thousands users worldwide who process some of the most difficult samples ores coal fly ash ceramics and plastics Milestone R amp D engineers were given the goal to develop the safest highest performing and most flexible microwave platform for laboratory applications No limits were set only goals This is ethical This is ETHOS 1 2 TECHNICAL SPECIFICATIONS e Microwave labstation for quality control for digestion drying and evaporation concentration procedures e Patented self sealing explosion resistant door e Single magnetron with static microwave diffuser for homogeneous microwave distribution e Installed microwave power 900Watt e Delivered microwave power 900Watt in 10Watt increments e Variable microwave pulse width from 0 1 to 5 e Unpulsed microwave emission at 250 Watt e Microwave cavity all made of 18 8 stainless steel housing with multilayer Teflon plasma coating applied at 350 C e Dimensions 35cm x 35cm x 35cm ca 45L volume e Built in exhaust system with automatic constant
5. ETHOS 900 Page 2 1 2 4 SAFETY TROUGH ELECTRICAL DESIGN The ETHOS microwave platform is equipped with a total of 10 microswitches to assure the highest safety conditions Four two on each side of the door fast release microswitches instantaneously interrupt the microwave emission whenever the door is opened previous picture One safety switch on the cabinet cuts off microwave emission whenever the cabinet is detached picture Two thermal switches on magnetron s body and other two on both wave guides cut off power in case of overheating picture 1 2 5 SAFETY THROUGH NOx MONITORING When HNO is used in the digestion process NOx gases are generated NOx gases may diffuse through the vessel walls or they are released in case of vessel overpressurization in the microwave cavity picture Exhaust fan NOx Sensor By monitoring the presence of NOx in the microwave cavity optional device when the preset NOx limits are exceeded the microwave power is automatically reduced triggering a beep signal Microwave emission increases again after the NOx concentration has returned to the preset limits Volatile losses are prevented resulting in safer working conditions and more consistent results ETHOS 900 Page 3 1 2 6 PERFORMANCE THROUGH MICROWAVE HARDWARE DESIGN The heart of the ETHOS platform is the innovative and patented microwave feed distribution system to the working cavity
6. PERFORMANCE THROUGH MICROWAVE HARDWARE DESIGN The heart of the ETHOS platform is the innovative and patented microwave feed distribution system to the working cavity Two 800Watt industrial magnetron ETHOS 1600 only each with its own high voltage power supply assure a powerful 1600Watt of microwave installed power picture The Milestone Safety Guide Page 4 Two high flow cooling fans guarantee peak performance of the magnetrons The microwaves are first fed into a pre mixing chamber From here an ingenious pyramid shaped rotating metal diffuser evenly distributes the microwaves in the cavity picture Surfaces are Teflon coated with the diffuser protected by an inert high density polypropylene plate This unique microwave design and the advanced microprocessor control assures optimal microwave distribution in the cavity thus preventing hot spots The installed power of 1600Watt has been limited by design to operate at approximately 2 3 of the maximum power 1000Watt to assure longer magnetrons lifetime The 1000Watt of delivered power is delivered in 10Watt increments to fit all types of applications The ETHOS 900 platform is powered by a 900Watt magnetron with a specially designed static diffuser to guarantee optimal microwave distribution in the cavity PERFORMANCE THROUGH VERSATILITY To fulfill the goals of making the ETHOS the most versatile microwave platform Milestone s engineers built 13
7. The Milestone Safety Guide Page 2 The microwave cavity door opens downwards to a flat horizontal position forming a stable work platform for handling microwave accessories before and after digestion procedures SAFETY TROUGH ELECTRICAL DESIGN The ETHOS microwave platform is equipped with a total of 10 microswitches to assure the highest safety conditions Four two on each side of the door fast release microswitches instantaneously interrupt the microwave emission whenever the door is opened previous picture One safety switch on the cabinet cuts off microwave emission whenever the cabinet is detached picture Two thermal switches on magnetron s body and two other on both wave guides cut off power in case of overheating picture The Milestone Safety Guide Page 3 SAFETY THROUGH NO MONITORING When HNO is used in the digestion process NOx gases are generated NOx gases may diffuse through the vessel walls or are released during vessel overpressurization in the microwave cavity picture Exhaust fan NOx Sensor By monitoring the presence of NOx in the microwave cavity optional device when the preset NOx limits are exceeded the microwave power is automatically reduced triggering a beep signal Microwave emission increases again after the NOx concentration has returned to the preset limits Volatile losses are prevented resulting in safer working conditions and more consistent results
8. Two 800Watt industrial magnetron ETHOS 1600 only each with its own high voltage power supply assure a powerful 1 600Watt of microwave installed power picture Two high flow cooling fans guarantee peak performance of the magnetrons The microwaves are first fed into a pre mixing chamber From here an ingenious pyramid shaped rotating metal diffuser evenly distributes the microwaves in the cavity picture Surfaces are Teflon coated with the diffuser protected by an inert high density polypropylene plate This unique microwave design and the advanced microprocessor control assures optimal microwave distribution in the cavity thus preventing hot spots The installed power of 1 600Watt has been limited by design to operate at approximately 2 3 of the maximum power 1 000Watt to assure longer magnetrons lifetime The 1 000 Watt of delivered power are delivered in 10 Watt increments to fit all types of applications The ETHOS 900 platform is powered by a 900 Watt magnetron with a specially designed static diffuser to guarantee optimal microwave distribution in the cavity ETHOS 900 Page 4 1 2 7 PERFORMANCE THROUGH VERSATILITY To fulfill the goals of making the ETHOS the most versatile microwave platform Milestone s engineers built 13 microwave leakage protected inlet outlet connectors Temperature and pressure sensor connectors for vacuum and inert gas supply can be all easily installed wit
9. minutes Power Watt 1 5 250 2 5 500 3 5 650 2 3 BASIC PROGRAM FOR 12 SAMPLES Step Time minutes Power Watt 1 8 250 2 8 500 3 8 750 Acid digestion guidelines Page 7 3 0 MICROWAVE ACID DIGESTION OF ENVIRONMENTAL SAMPLES A number of microwave digestion methods for environmental samples have been approved by the US EPA Environmental Protection Agency US EPA 3015 SW 846 Update II Microwave assisted acid digestion of aqueous samples US EPA 3051 SW 846 Update II Microwave assisted acid digestion of sediments slugs soils and oils US EPA 3052 SW 846 Update III Microwave assisted acid digestion of siliceous and organically based matrices A brief explanation of the methods is given here more detailed information are available from your Milestone local supplier up on request 3 1 US EPA METHOD 3015 Sample amount 45mL Reagents 2 5mL HNO and 2 5mL HCI when analyzing the solution with FLAA or ICP 5mL HNO only when analyzing the solution with FLAA GFAA ICP or ICP MS Microwave digestion time 20 minutes Temperature to reach 160 C within 10 minutes and to remain between 165 170 C for other 10 minutes 3 2 US EPA METHOD 3051 Sample amount 0 5g Reagent 10mL HNO Acid leaching method Microwave digestion time 10 minutes Temperature to reach 170 C within 5 5 minutes and to remain between 170 180 C for the balance of 10 minutes 3 3 US EPA METHOD 3
10. 0 3 00 05 00 800 0 150 0 4 00 08 00 800 0 150 0 5 00 00 00 0 0 0 0 6 00 00 00 0 0 0 0 7 00 00 00 0 0 0 0 8 00 00 00 0 0 0 0 9 00 00 00 0 0 0 0 10 00 00 00 0 0 0 0 TIME AT TEMPERATURI 1607 HOLD 150 140 120 RAMP 100 2 i 80 E 2 HOLD 60 40 RAMP 20 0 T T T 0 5 10 15 20 25 Time minutes If during the 1 step the temperature will reach 60 C then the program will skip the remaining time of the 1 step to proceed directly with the 2 step time at temperature 5 minutes at 60 C If during the 3 step the temperature will reach 150 C then the program will skip the remaining time of the 3 step to proceed directly with the 4 step time at temperature 8 minutes at 150 C Press ENT on the keyboard and the display will show TWIST ON 1 MODE 1 ON OFF ENT OK Software mod lev 6 17 Page 5 The TWIST function allows an alternate 360 C rotation of the carousel or of the rotor This is required when the ETHOS 900 comes with an APC 55 Automatic Pressure Control or with an ATC 300 Automatic Temperature Control device to avoid bending of the Teflon connecting tubing between the reference vessel and the pressure transducer APC 55 and to avoid the bending of the temperature sensor ATC 300 Press the key MODE 1 to activate ON or deactivate OFF the TWIST function Press ENT on the keyboard and the display will show VENT hh mm ss 1 ENT OK The ventilation step is very important an
11. be seen through the plastic connection does reflect microwaves back to the cavity not allowing any leak through the opening Do not block or obstruct the openings since air circulation trough the microwave cavity is an important safety aspect of microwave closed vessel acid digestion Overiew of the back side of the ETHOS 900 picture ETHOS 900 Page 11 Notice in the upper part left the open connection for the plastic hose and at right the second connection closed for a second otional blower Detail of the interfaces of the ETHOS 900 picture at left a standard RS 232 9 pin interface port to be used for connecting the microwave to external devices at righ the special 50 pin interface port to be used for connecting the ETHOS 900 to the control terminal model 240 Detail of the left panel of the ETHOS 900 picture showing the connection to the power cord at right down the power connection to external devices right up and two fuses More details about this subject are available in the ETHOS Service Manual ETHOS 900 Page 12 1 5 3 CONTROL TERMINAL 240 INTERFACE PORTS The picture below shows the back side of the control terminal model 240 From left to right it is possible to see the following interface ports e RS 232 9 pin for connecting the ETHOS 900 to an external PC e RS 232 9 pin for connecting the ETHOS 900 to an external balance a limited number of balances
12. can be interfaced e special 50 pin interface port for connecting the control terminal 240 to the ETHOS 900 main unit e Centronix interface for connecting the ETHOS 900 to any printer parallel port e analogue port for connecting the ETHOS 900 to an external laboratory recorder 1 5 4 ETHOS 900 SETUP Connect the 50 pin interface cable supplied to the back side port of the ETHOS 900 and use a screwdriver to fix them well picture Connect the other end of the 50 pin cable to the control terminal 240 and again use a screwdriver to fix them well picture ETHOS 900 Page 13 WARNING The free end of the exhaust hose should be placed Both the 50 pin connections must be very tight under a fume hood or directly outside damages may occour when the ETHOS 900 and the the laboratory picture control terminal 240 are not properly connected Plug in the supplied power cord at the back side of the ETHOS 900 picture Introduce now the L shaped adapter to the exhaust outlet located at the left of the ETHOS 900 back panel Connect the exhaust hose to the L shaped adapter picture ETHOS 900 Page 14 A LOOK AT THE HIDDEN SIDE OF THE ETHOS UNIT The most important safety features are the ones you don t see from the outside For this reasons Milestone lets you see under the cabinet cover of the ETHOS SAFETY THROUGH MECHANICAL DESIGN The ETHOS is not a kitchen t
13. flow control acid and organic solvent resistant with flow rate 5m minute e Control terminal 240 with high resolution graphic 128 x 240 LCD display black white with backlight and flat keyboard alphanumeric display 12 special function keys e Storage of up to 20 programs each program has up to 10 time power pressure internal temperature external temperature steps e Outputs 1 parallel Centronix for external printer to print out reports 2 serial ports RS 232 for connecting PC for data base reporting and programming of the unit balance for weighing data storage additional port for analog data for connecting a laboratory recorder Dimensions of the microwave unit 55cm large x 55cm long and 70cm high e Power supply 230V 50 or 60Hz 7A 1 600Watt e Weight approximately 85kg P N Description Power supply 44006 ETHOS 900 complete 220V 50Hz 44056 ETHOS 900 complete 220V 60Hz ETHOS 900 Page 1 1 2 1 A LOOK AT THE HIDDEN SIDE OF THE ETHOS UNIT The most important safety features are the ones you don t see from the outside For this reasons Milestone lets you see under the cabinet cover of the ETHOS 1 2 2 SAFETY THROUGH MECHANICAL DESIGN The ETHOS is not a kitchen type nor a commercially modified kitchen microwave unit it is a rugged heavy duty professional system designed to guarantee years and years of trouble free and safe operation The hardware The m
14. have no molded or machined threads to be chemically attacked and weakened by acid vapors during vessel venting and opening This unique feature is an important factor in the durability and safety of Milestone digestion vessels All digestion vessels in MDR rotors are protected by a patented reclosing vent and reseal relief valve mechanism Vessels fitted into a MDR rotor body are sealed for microwave digestion and proper relief valve functioning using a calibrated torque wrench The torque wrench ensures vessels are sealed for maximum operating pressure and will safely vent when a buildup of decomposition gases in excess of vessel s maximum operating pressure is reached Microwave digestion of organic samples frequently involves exothermic reactions which instantaneously generate large amount of decomposition gasese CO and NOx as the sample is oxidized For proper overpressurization protection of microwave digestion vessels the venting capacity of the relief device must be equal or higher than the rate of decomposition gas formation Only Milestone s relief valve is capable of instantaneously venting excess decomposition gases and resealing the vessel for completation of the digestion procedure The digested sample is retained inside the vessel for analysis The Milestone Safety Guide Page 8 MDR SAFETY The above drawing clearly show the instantaneous release of overpressure due to the deformation of the HTC safety spring The f
15. shows START RUNNING PRG 1 P 0 T 1 0 T2 0 Note that when the APC 55E the ATC 300E or the IRTC 500 options are installed in the ETHOS 900 the actual values of pressure internal temperature and external temperature will be shown Press the START key to start the program number 1 the display shows OW 00 00 05 Pl CHECK AND START During the brief pause that follows the magnetron will be warmed up after 5 seconds the program is started During running of the program the display shows step by step the microwave power in Watt the time remaining in hours minutes and seconds and the actual values of pressure internal temperature and external temperature However the following circumstances may occur gt DOOR NOT CLOSED lt The door of the ETHOS 900 has not been properly closed the microwave program is hold until the door is closed gt TWIST NOT READY lt The twist function is not properly working this may cause damages to the pressure and temperature sensors The microwave program is interrupted The microwave program can be stopped at anytime by pressing the STOP key or by lowering the door handle Pressing the STOP key the display shows USER BREAK Only if ventilation time was preset the program will automatically proceed with the ventilation time After the ventilation time the display shows Software mod lev 6 17 Page 14 PROGRAM 1 IS READY POWER IS OFF On the contrary if no venti
16. the bottom of the safety shields approximately 2cm from the base at the level of the solution Putting two shields aside the deformation may be evidenced picture and replacement is necessary If HNO is often used to digest samples than the upper part of the safety shield may assume an orange like color due to a chemical attack of the HTC surface by the HNO3 This is normally not a problem unless the mechanical properties of HTC are compromised MDR technology Page 24 1 0 SOFTWARE MODEL LEVEL 6 17 FOR ETHOS 900 1 1 HOW TO CREATE AND STORE A NEW PROGRAM NOTE In order to make understanding of the following chapter clearer and easier we have opted for the representation only of the upper window shown by the control terminal display The following example will be described PROGRAM 1 Step Time hh mm ss Power Watt Pressure bar Int Temp CC Ext Temp C 1 00 05 00 250 3 150 70 2 00 05 00 400 6 180 80 3 00 04 00 500 10 210 80 Ventilation 00 03 00 Switch on the main switch of the ETHOS 900 located on the front panel The control terminal 240 display will alternatively show MultiQUANT SW V 6 17 M 9_1d77 After a few seconds the display will show F1I WORK F2 EDIT F3 READIN F4 READOUT Press F2 key the display will show EDIT PROGRAM 1 1 20 ENT OK Press ENT to confirm the display will show TIME hh mm ss 1 1 ENT OK Introduc
17. the software Also the gas sensor sensitivity can be set There are four sensitivity steps HIGH MEDIUM LOW and OFF It is possible to select one of these possibilities with the MODE1 key When the gas sensor is activated during a microwave program run microwave are turned OFF if the preset level is reached A warning message appears on the display When the gas concentration decreases below the preset level the microwave program is continued and the warning message disappear Select HIGH MEDIUM LOW or OFF and confirm the choice by pressing ENT key The display shows DATE 30 03 98 ENT OK Press the STOP key to leave the SYSTEM sub menu and the display shows F1 SYSTEM F2 VALUES F3 BALANCE F4 PC Press the F2 key to visualize the VALUES sub menu the display shows the software model level as well as the actual values of pressure internal temperature and external temperature SW_V 6 17 M 9_0d77 P 0 T1 0 T2 0 Press the STOP key to leave the VALUES sub menu and the display shows F1 SYSTEM F2 VALUES F3 BALANCE F4 PC Press the F3 key to visualize the BALANCE sub menu the display shows direct readout of the balance when this is connected WEIGHT 0 2308g 0 ZERO ENT PRINT Press the 0 key to tare the balance or press the ENT key to printout the balance readout By pressing the STOP key the display turns back to the main menu F1 SYSTEM
18. without any intermediate seal ring which could deteriorate in contact with acid vapors The elimination of a threaded cover prevents all problems connected with thread deformation or impurities on threads The vessel has normally a volume of 100mL A high resistant HTC safety shield prevent lateral deformation of the vessel 1 4 MATERIALS USED FOR THE MANUFACTURE OF MDR VESSELS AND SAFETY SHIELD 1 4 1 TFM TEFLON TFM is often used for the manufacture of covers and vessels of the MDR rotors TFM is a Hoechst trade name for chemically modified PTFE TFM Teflon has a very dense structure with smooth surface and low permeability to gases and vapors TFM Teflon is chemically inert to most mineral acids and combinations thereof It is a thermal insulator with a very high stability to temperature extremes TEM Teflon is microwave transparent Its maximum working temperature for extended use is 260 C for short time 300 C The melting range is 320 340 C 1 4 2 PFA TEFLON PFA is often used for the manufacture of vessels of the MDR rotors PFA Teflon is a melt processable fluoroplastic material which can be extruded and therefore manufactured in relatively low cost vessels It shows a good all round chemical resistance It is microwave transparent and termal insulator The maximum working temperature is up to 260 C the melting temperature is about 300 C 1 4 3 HTC HTC plastics are used for the manufa
19. 052 Sample amount up to 1 0g Basic reagents 9mL HNO and 3mL HF Alternative combinations include HCl for Erg BA SB Fe and Al determination H O for organic samples and H O to slow down exothermal reaction Goal is total sample decomposition Microwave digestion time 15 minutes Temperature to reach 180 C within 5 minutes and to remain between 175 185 C for 10 minutes Acid digestion guidelines Page 8 4 0 MICROWAVE ACID DIGESTION OF INORGANIC SAMPLES Inorganic samples group includes metals alloys oxides ores rocks slags ceramics etc 4 1 CHEMISTRY Sample preparation procedure are strongly dependent on the chemical nature of the material to be digested abd on the elements to be determined The microwave acid s choice is often the same as used with conventional methods 4 2 MICROWAVE PROGRAM Most inorganic samples show non exothermal reactions and do not produce large amount of gases The sample amount does not affect the ratio temperature pressure as much as with organic samples The digestion efficiency strongly depends on the digestion temperature therefore the target is to bring the solution to the highest temperature in the shortest time first step and to hold this temperature until the digestion is complete second step For difficult samples requiring temperatures higher than 200 C a high pressure rotor MDR 1000 6S should be used while for easier samples requiring temperature below
20. 200 C a medium pressure rotor MDR 300 10S is enough As a matter of fact when samples such as sand 1g are to be digested with 4mL HF and 1mL HNO a suitable program would be Step Time minutes Power Watt 1 10 650 2 10 350 The above program refers to the simultaneous digestion of 6 samples A library of nearly 400 sample preparation methods is available from your local Milestone distributor Acid digestion guidelines Page 9
21. C 300 Automatic temperature control without sensor 33962 Temperature sensor model MW1Au gold plated 30009 SoftWAVE Method Development rev 2 0 requires PC not supplied 1 4 ETHOS 900 COMPATIBILITY WITH DIGESTION DRYING AND CONCENTRATION ROTORS The ETHOS 900 can accomodate the following acid digestion vessels and rotors P N Description 41400 AC 10 Advanced Carousel complete with 10 Vessels and Shields 34181 MDR 1000 3 complete 35301 MDR 1000 6S complete 41100 MDR 300 10S complete with PFA vessels 41200 MDR 300 10S complete with TFM vessels 35100 HPR 1000 10S rotor complete 35180 MPR 300 12S Rotor complete The ETHOS 900 can accomodate the following drying and evaporation concentration rotors P N Description 34670 MCR 1 Drying rotor in polypropylene 3 5L 40103 MCR 1 Drying rotor in polypropylene 6 5L 34649 MCR 6 Concentration rotor 6 position empty 34940 MCR 8 Concentration rotor 8 position empty 34510 MCR 12 Concentration rotor 12 position empty The MCR series rotors require a vacuum source Below are the options available P N Description 40018 FAM 40 Fume absorbing module 220V 50Hz 40019 FAM 40 Fume absorbing module 115V 60Hz 84245 VAC 20P Vacuum pump system 220V 50Hz 84254 VAC 60 Vacuum pump system 220V 50Hz ETHOS 900 Page 7 1 5 ETHOS 900 INSTALLATION
22. EALLY SURE Ex TOTAL PRG TIME gt 1h Press the ENT key and the display shows START RUNNING PRG P 0 T1 0 T2 0 Now the program is available to work Otherwise if you want to change the program press the STOP key when the warning message appears then press again the STOP key until the main menu is reached FI WORK F2 EDIT F3 READIN F4 READOUT Software mod lev 6 17 Page 19 1 12 SOFTWARE INITIALIZATION Every time either a CPU board or a EPROM is replaced the system needs to be reinitialized Proceed as follows e start with ETHOS 900 in OFF conditions e press the STOP key on the control terminal e keeping pressed switch ON the ETHOS 900 e remain in this position until a buzzer sound is heard e enter a new working program as previously described Software mod lev 6 17 Page 20 1 13 MULTIQUANT MODE The ETHOS 900 besides being a digestion system can also operate as moisture solids analyzer For determination of volatile elements the operator must go to the program part READIN by pressing the F3 key from the main menu Refer to this section only when a balance and a printer are connected to the ETHOS 900 The basic principle of the multtQUANT mode is that volatile moisture in samples are determined by weighing the samples themselves before and after a drying process The difference between the initial weight read in and the final weigh read out is determine
23. F2 VALUES F3 BALANCE F4 PC Press F4 to interface the ETHOS 900 to an external computer By an appropriate software the ETHOS 900 is fully operated by an external computer COMPUTER ON LINE Press the STOP key to return to the main menu By pressing the F5 key from the main menu a printout of whatever the display shows is activated Software mod lev 6 17 Page 17 1 11 ERROR MESSAGES In case the operator has any difficulty with the control terminal software the basic rule is to press the STOP key to return to the main menu Switching ON OFF the unit will cause resetting and going back to the main menu Work programs remain unchanged 1 11 1 TWIST FUNCTION This function has been introduced for higher safety of operation Basic setting is TWIST ON If the operator is using an MDR rotor fitted with pressure and or internal temperature control the twist function must be ON as otherwise the sensor tubing will be damaged TWIST not ready POWER IS OFF 1 11 2 ROTOR CONTROL If the ETHOS 900 is fitted with an IRTC 500 it is important to activate the rotor control therefore at the following step ROTOR CTRL ON1 MODE1 ON OFF ENT OK 1 11 3 OVERHEATING As an extra safety the ETHOS 900 magnetron are provided with overheating thermal safety switches In the remote event of hardware overheating the following message appears gt DOOR NOT CLOSED lt And then CONTINUE CLOSE DOOR ABO
24. M 1 1 20 ENT OK The arrow keys allow to select the program to be created Note that the arrow keys allow the selection of the stored programs only in both work and edit mode Software mod lev 6 17 Page 11 1 7 HOW TO MODIFY A PREVIOUSLY STORED PROGRAM When the display shows PROGRAM 1 EXISTS DEL NEW ENT OK Press the ENT key and the display will show TIME 00 05 00 1 1 ENT OK Using the arrow keys as well as the number keys it is possible to modify microwave emission time power parameters as P T1 and T2 in each of the ten steps included in the program As soon as the parameter has been modified press the STOP key to come back to the main menu Software mod lev 6 17 Page 12 1 8 PARAMETERS CHOICE 1 8 1 MICROWAVE POWER The desired microwave power can be set in 10Watt increments up to a maximum of 900 Watt For any value for instance 300Watt it is sufficient to introduce 30 as the first 0 is already fixed 1 8 2 PRESSURE The APC 55E Automatic Pressure Control is required A pressure up to 55bar can be set when operating with a MDR 1000 6S rotor At the set pressure level the microwave emission will be controlled 1 8 3 TEMPERATURE 1 The ATC 300 Automatic Temperature Control is required A temperature up to 240 C can be set starting from which the microwave emission will be controlled 1 8 4 TEMPERATURE 2 The IRTC 500 Infrared Temperature Control is required An ex
25. RT STOP If this error message is not due to the ETHOS 900 door left open then interrupt the microwave program After cooling the system can be regularly operated again 1 11 4 BATTERY The ETHOS 900 CPU is provided with a Lithium battery to save the storing in memory of the working programs The lifetime of the memory buffer battery is approximately 3 years and therefore it should be replaced after this time period If the battery is empty the software will give a user message and delete all programs BATTERY IS EMPTY ALL PROGRAMS ARE KILLED A double beep follows this message If you still want to work with a low battery you have to enter the whole program after power on the ETHOS 900 1 11 5 LONG TIME OPERATION PROGRAM Software mod lev 6 17 Page 18 All reactions over 30 minutes and above 250Watt should only be carried out with the ATC 300 Automatic Temperature Control device installed and in use and only after contacting first the Milestone representative in your country for advise The next function has been introduced to protect the ETHOS 900 from overheating problems caused by long time programs more than hour If the program being used is longer than 1 hour when pressing FI WORK a three times warning message appears S WARNING pi TOTAL PRG TIME gt 1h Press the ENT key and the display shows oka ARE YOU SURE aa TOTAL PRG TIME gt 1h Press the ENT key and the display shows aia ARE YOU R
26. TC safety spring on the top side picture Place the TFM Teflon indicator ring on the cover and push it down completely until it fits the groove of the HTC safety shield as shown by the next picture Locate the HTC safety spring onto the HTC adapter plate picture Position the polypropylene rotor body on the work station use the black coloured dot on the rotor body as reference point to fit the rotor body on the work station picture Introduce the vessel vertically into one of the numbered niches carved along the periphery of the 10 position polypropylene rotor body Notice the position of the venting hole located in the TFM Teflon indicator ring The hole must face outside so that in case of venting no hot acid vapors can damage the polypropylene rotor body picture MDR technology Page 8 It may be useful now to fix the vessel inside its location without a complete closing Take the torque wrench and remove the plastic adaptor picture Use the adaptor to fix the vessels as shown in the next picture Repeat the same operations for the remaining nine vessels then put the external protection ring around the rotor body picture Take the torque wrench and set the indicator to the CLOSE position as shown in the next picture Tighten the HTC screw in the upper part of the rotor body using the torque wrench Make long rotations refer to the two next pictures instead of short
27. The hole must face outside so that in case of venting no hot acid vapors can damage the polypropylene rotor body picture It may be useful now to fix the vessel inside its location without a complete closing Take the torque wrench and remove the plastic adaptor picture Use the adaptor to fix the vessels as shown in the next picture Repeat the same operations for the remaining nine vessels then put the external protection ring around the rotor body picture Take the torque wrench and set the indicator to the CLOSE position as shown in the next picture Tighten the HTC screw in the upper part of the rotor body using the torque wrench Make long rotations refer to the two next pictures instead of short ones and do proceed slowly until you hear a clicking sound informing that the vessel is properly closed inside its niche WARNING Stop turning the torque wrench when the click is heard MDR technology Page 17 In fact the torque wrench may overload the HTC safety spring if further rotation is applied Make slow 90 rotations with the torque wrench to get a better control of the correct closing of the vessel click sound Slide in the MDR 1000 6S rotor inside the microwave cavity of the ETHOS 900 1600 picture Turn the rotor until it matches the drive adaptor located at the center of the microwave cavity base picture The MDR 1000 6S rotor is now
28. at right This is the unique operating principle of the microwave digestion rotor technology of Milestone An indicator ring located next to the cover remains in the upper position in case of vessel venting The picture belows shows a vessel in normal conditions and at right a vessel after venting MDR technology Page 5 1 7 MDR 300 10S The MDR 300 10S medium pressure rotor contains 10 vessels for acid digestion of routine and moderately difficult samples at operating pressure up to 30bar 435psi The MDR 300 10S is available in two different versions with PFA Teflon vessels or with TFM Teflon vessels e P N 41100 MDR 300 10S with PFA Teflon vessels e P N 41200 MDR 300 10S with TFM Teflon vessels 1 7 1 MDR 300 10S CONFIGURATIONS The MDR 300 10S rotor with PFA Teflon vessels has P N 41100 and it is composed by the following items P N Quantity Description 34642 1 Rotor body 34021 10 Safety spring 34114 10 Adapter plate 34115 10 TEM Teflon cover 34049 10 Indicator ring 34121 10 PFA Teflon vessel 34602 1 Safety shield set of 10 The MDR 300 10S rotor with TFM Teflon vessels has P N 41200 and it is composed by the following items P N Quantity Description 34642 1 Rotor body 34021 10 Safety spring 34114 10 Adapter plate 34115 10 TEM Teflon cover 34049 10 Indicator ring 33802 10 TEM Teflon vessel 34602 1 Safety shield set o
29. ates phosphates and most metals are soluble with the exception of AgCI HgCl and TiC excess of HCl improves the solubility of AgCl converted into AgCl strong complexing nature widely used for iron based alloys because of its ability to hold large amounts of chloro complex in solution other complexes formed are Ag I Au II Hg I1 Ga IID TI D Sn IV Fe ID and Fe IID it does not dissolve oxides of Al Be Cr Ti Zr Sn and Sb sulphates of Ba and Pb group II fluorides SiO TiO and ZrO 250 30 25 200 S 20 L 150 5 p T 15 5 Q Ww 100 cB 10 50 5 0 T T T T 0 0 300 600 900 1200 Time seconds The graphic above represents the temperature and pressure profile of hydrochloric acid up on microwave heating Notice that pressure has been controlled at 25bar resulting in a temperature of 205 C The Milestone Safety Guide Page 11 HYDROFLUORIC ACID Hydrochloric acid has the following properties ACID DIGESTION e Boiling point is 108 C at 40 concentration e nonoxidizing strong complexing nature e used in digestion of minerals ores soils rocks and even vegetables containing silicates e major use is the decomposition of silicates according with this reaction SiO 6HF gt H SiF 2H O e often used in combination with HNO or HCIO EVAPORATION CONCENTRATION e Following dissolution many analyses require removal of HF to prevent equipment
30. ay will show PROGRAM 1 EXISTS DEL NEW ENT OK Press the DEL key and the display will show TIME Hh mm ss 1 1 ENT OK The previous program has been deleted and a new program can be stored Cancellation of a program can be verified as no asterisk will appear before the program number Press the STOP key twice and the display will show FI WORK F2 EDIT F3 READIN F4 READOUT Software mod lev 6 17 Page 8 1 4 HOW TO DELETE ALL PROGRAMS FI WORK F2 EDIT F3 READIN F4 READOUT Press the F2 key and the display will show EDIT PROGRAM n 1 20 ENT OK Press the 0 key and the display will show EDIT PROGRAM 1 20 ENT OK The symbol _ will blink Press the ENT key and the display will show KILL ALL PROGRAMS SURE DEL YES When the DEL key is pressed all the programs in memory will be cancelled if the STOP key is pressed twice then the display will return to the main menu Software mod lev 6 17 Page 9 1 5 HOW TO VERIFY DELETION OF A PROGRAM Press the F1 key and the display will show Press the ENT key and the display will show Software mod lev 6 17 Page 10 16 ARROWS FUNCTIONS When the display shows WORK PROGRAM 1 20 ENT OK The arrow keys allow selection of the work program sequence for instance upwards from 1 to 2 3 etc with gt and downwards from 3 to 2 1 etc with lt When the display shows EDIT PROGRA
31. bed here is part of the US EPA approved method 3052 for the microwave acid digestion of environmental samples 1 Store TFM and PFA Teflon parts in 1 1 subboiled HCI overnight at 80 120 C 2 rinse with bidistilled water 3 Store in 1 1 subboiled HNO overnight at 80 125 C 4 rinse with bidistilled water store in bidistilled water 6 allow parts to dry in a particle and fume free environment A WARNING It is mandatory to replace springs with thickness lower than 7 3mm Their use may cause severe damages to other components of the rotor MDR technology Page 23 1 9 4 HTC ADAPTER PLATE TFM TEFLON COVER TFM TEFLON INDICATOR RINGS AND TFM OR PFA TEFLON VESSEL The HTC adapter plates the TFM Teflon covers the TFM Teflon indicator rings and the TFM or PFA Teflon vessels shown in a picture below do not practically undergo any deformation if properly used They have to be replaced only in case of damage or deformation A visual inspection of the above items has to be done before every digestion 1 9 5 PRESSURE SCREW The pressure screw picture in the rotor may slightly lose smoothness Threads can be re made by a Service Technician using a proper stainless steel tool 1 9 6 SAFETY SHIELDS After long time operation the safety shields may show some swelling due to the high heating conditions Lifetime is estimated to be hundreds of digestions Check for visible deformation at
32. crowave digestion may be classified in two main groups e nonoxidizing acids such as hydrochloric acid hydrofluoric acid phosphoric acid diluted sulfuric acid and diluted perchloric acid e oxidizing acids such as nitric acid hot concentrated perchloric acid concentrated sulfuric acid and hydrogen peroxide 1 2 NITRIC ACID Nitric acid has the following properties e boiling point is 120 C at 65 concentration e poor oxidizing strength at concentrations less than 2M oxidizing strength increases with concentration and reaction temperature e most common acid for oxidation of organic matrices with this typical reaction CH x 2HNO gt CO g 2NO 2H O e it dissolves most metals forming soluble nitrates exceptions are Au and Pt not oxidated and Al B Cr Ti and Zr passivated e these metals require acid mixtures or diluted nitric acid e often mixed with H O HCl and H SO e available in high purity for trace level analysis 250 30 25 200 g 20 L 150 5 p B Ai Ww 100 13 H 10 50 5 0 T T T T 0 0 300 600 900 1200 Time seconds The above graphic represents the temperature and pressure profile of nitric acid up on microwave heating Notice that pressure has been controlled at 25bar resulting in a temperature of 225 C Acid digestion guidelines Page 1 1 3 HYDROGEN PEROXIDE Hydrogen peroxide is an oxidizing agent 2H O gt 2H O O added to nitric acid i
33. cture of safety spring adapter plate and safety shield They are characterized by the sequence ether ether keton keton When HTC are used for the safety shield they are reinforced with glass fiber HTC have high mechanical strength to high temperatures and good chemical resistance The maximum service temperature for extended use is 250 C MDR technology Page 2 1 5 ACCESSORIES OF THE 1 5 2 TORQUE WRENCH MDR MONOBLOC ROTORS 1 5 1 WORK STATION The torque wrench P N 34000 is used to properly and safely close open the vessels of the MDR rotors The work station P N 34030 allows fixing of every kind of monobloc rotors in order to properly close and open the vessels drawing 1 5 3 INSTRUCTION OF USE Apply a smooth steady pull until you hear a click Release your pressure on the handle and the torque wrench will automatically reset itself provided the ratchet reverse lever G is in position toward the indicator H Refer to the drawing above The torque function does work only when the reverse lever G is in position 1 By placing it in position 2 the torque function is neutralized the the wrench becomes a normal The work station is made of polypropylene and it is reversible ratchet provided with four anti skid rubber feet The torque is factory set at 22 5Nm for all MDR rotors Note that for correct torque setting the tool should be gripped properly on the middle of the handle and n
34. d and statistically calculated Quitting the main menu and pressing F3 READIN the operator gets into the multiQUANT menu Introduce the sample identification maximum 9 letters replacing the writing MLS GmbH word e IDNO Use the arrow keys to go forward and backwards in the alphabet use the asterisk to switch from capital to small letters use the 0 9 keys to write numbers e NO SAMPLES Indicates the number of samples to be weighed tested e ITARA Store the tare of the 1st sample e 1TARA S The 1st sample is weighed and the value is stored in memory e 2TARA Store the tare of the 2nd sample e 2TARA S The 2nd sample is weighed and the value is stored in memory and so on e F4 READOUT Weighing of final weight and statistical calculation with print out of reports In case during weighing both read in and read out there are one or more errors sample lost burnt defective vessel etc it is not necessary to repeat the complete sequence but single values can be rejected with the READOUT step An exclamation mark will appear and the value will remain out of the statistical calculation The procedure is reversible Before quitting with the STOP key it is suggested to press the F5 key to have printout of the modified values Software mod lev 6 17 Page 21 1 0 GUIDELINES FOR MICROWAVE ACID DIGESTION 1 1 INTRODUCTION TO THE REAGENTS MOST COMMONLY USED IN MICROWAVE DIGESTION The acids used in mi
35. d should not be omitted It serves to cool down the vessels inside the microwave cavity before removing the rotor for further water cooling It is therefore an important safety issue In the above mentioned example the ventilation step lasts 3 minutes therefore digit 0 0 0 and 3 The display will show VENT 00 03 ss 1 ENT OK Press ENT on the keyboard to confirm and the display will show PROGRAM 1 IS READY And then Fl WORK F2 EDIT F3 READIN F4 READOUT End of program setting Software mod lev 6 17 Page 6 1 2 HOW TO VISUALIZE A STORED PROGRAM Switch on the ETHOS 900 unit the display will show FI WORK F2 EDIT F3 READIN F4 READOUT Press the F2 key the display will show EDIT PROGRAM 1 1 20 ENT OK The asterisk indicates that the program number 1 has been previously stored Press the key ENT and the display will show PROGRAM 1 EXISTS DEL NEW ENT OK Press the key ENT to visualize in sequence the previously entered program and parameters To end the visualization press the STOP key and the display will show EDIT PROGRAM 1 ABORTED And then after pressing the STOP key the display will show FI WORK F2 EDIT F3 READIN F4 READOUT Software mod lev 6 17 Page 7 1 3 HOW TO DELETE A PROGRAM Fl WORK F2 EDIT F3 READIN F4 READOUT Press the F2 key and the display will show EDIT PROGRAM pall 1 20 ENT OK Press the ENT key and the displ
36. damage or to resolubilize insoluble fluorides e many analytes such as As B Se Sb Hg and Cr may volatilize COMPLEXATION e Alternative approach to remove HF from the solution by addition of Boric acid e the following reactions take place H 3BO 3HF gt HBF OH 2H O and HBF OH HF gt HBF H20 e 10 50 times excess Boric acid enhances reaction rate 250 30 25 200 S 20 L 150 i p T 15 5 Q Ww 100 b 10 50 5 0 T T T T 0 0 300 600 900 1200 Time seconds The above graphic represents the temperature and pressure profile of hydrofluoric acid up on microwave heating Notice that pressure has been controlled at 25bar resulting in a temperature of 240 C The Milestone Safety Guide Page 12 SULFURIC ACID Sulfuric acid has the following properties e boiling point is 340 C at 98 concentration exceeding the maximum working temperature of TFM Teflon vessels e careful reaction monitoring is required to prevent vessel damages e it destroys organics by dehydrating action e many sulfates are insoluble Ba Sr Pb 350 10 300 8 250 F 2 w 200 7 5 2 v 5 E amp 150 2 T4 o 100 2 50 0 to 0 150 300 450 600 Time seconds The above graphic represents the temperature and pressure profile of sulfuric acid up on microwave heating Notice that temperature has been controlled at 300 C for 1 minute only without any pressure increas
37. e It is clear that the use of concentrated sulfuric acid in the MDR rotors poses significant problems because of its high boiling point 300 C are critical for TFM Teflon vessels and simply too high for PFA Teflon vessels they melt down at such temperature It is therefore advisable to use sulfuric acid only with a strict temperature control The Milestone Safety Guide Page 13 1 0 MDR TECHNOLOGY Milestone patented microwave digestion rotor MDR technology provides analysts with unsurpassed performance capabilities and the highest standard of safety in closed vessel microwave digestion MDR rotors hold multiple microwave digestion vessels in a high strength one piece monobloc rotor body This unique design securely retains sample vessels during microwave digestion and subsequent venting of decomposition gases for maximum user safety The digestion vessels used in MDR rotors have no molded or machined threads to be chemically attacked and weakened by acid vapors during vessel venting and opening This unique feature is an important factor in the durability and safety of Milestone digestion vessels All digestion vessels in MDR rotors are protected by a patented reclosing vent and reseal relief valve mechanism Vessels fitted into a MDR rotor body are sealed for microwave digestion and proper relief valve functioning using a calibrated torque wrench The torque wrench ensures vessels are sealed for maximum operating
38. e the desired time of the Ist step 5 minutes in our case by pressing 0 0 0 and 5 on the keyboard The display will show TIME 00 05 ss 1 1 ENT OK Press ENT to confirm the display will show POWER OW 1 1 gt 900 ENT OK It is now possible to enter the microwave power level of the 1 step 250Watt in our case Press 2 and 5 on the keyboard and the display will show POWER 1 250 W Software mod lev 6 17 Page 1 1 1 gt 900 ENT OK Press ENT to confirm the display will now request the values for pressure internal temperature and external temperature WARNING The values of pressure internal temperature and external temperature shall be set only when the ETHOS 900 is supplied with either one of the following control devices APC 55 Automatic Pressure Control ATC 300 Automatic Temperature Control and IRTC 500 Infra Red Temperature Control If these devices are not installed in the ETHOS 900 simply press ENT three times to skip these steps The display will show PRESSURE B 1 1 gt 100 ENT OK Press 3 on the keyboard and the display will show PRESSURE 3B 1 1 gt 100 ENT OK Press ENT to confirm the value the following message will appear TEMP 1 ie 1 1 gt 400 ENT OK Press 1 5 and 0 150 C on the keyboard and the display will show TEMP 1 150 C 1 1 gt 400 ENT OK Press ENT
39. ents This is especially true if any trace of water or acid is left between the internal wall of the safety shields and the external walls of the vessels e Do not use ice to cool down the rotor after microwave heating as the thermal shock could damage the safety shield e To wash all kind of vessels it is advisable to make use of one of the following procedures 1 9 1 RAPID CLEANING PROCEDURE 1 Add 5mL HNO in each vessel close the vessels inside the rotor as for a normal digestion 3 start the following microwave program 6 vessels 10 minutes 500Watt or 10 vessels 10 minutes 650Watt 4 cool down and open the vessels 5 rinse the vessels with bidistilled water 1 9 3 SAFETY SPRING After long time digestions and long term use the HTC made springs are flattened and lowered The lifetime of the spring may vary depending on the working conditions pressure temperature of the rotor but it can be estimated in approximately 100 digestions A new spring is 8 0mm thick picture 8 mm If the lowering measures less than 0 7mm replacement is necessary A special propylene tool P N 40053 able to check the spring thickness is available from Milestone As shown by the picture below the slot measures 7 3mm if the spring can be introduced without forcing inside the slot then the spring has to be replaced 1 9 2 US EPA RECOMMANDED CLEANING PROCEDURE The cleaning procedure briefly descri
40. f 10 MDR technology Page 6 1 7 2 HOW TO OPERATE WITH THE MDR 300 10S ROTOR The above procedure relates to the use of a MDR 300 10S with TFM Teflon vessels P N 41200 The same sequence can be followed when using a MDR 300 10S with PFA Teflon vessels P N 41100 WARNING The wall surfaces of the HTC protection shield as well as the outer wall of the TFM Teflon vessel must be dry and clean Damages may occour otherwise 1 7 3 SAMPLE WEIGHING REAGENTS ADDITION AND VESSEL CAPPING Place a TFM Teflon vessel directly on the balance plate The weight of the TFM Teflon vessel is about 75g therefore most analytical balances may be used for the pourpose Tare the vessel and directly weigh the sample by placing it inside the vessel Try to reduce as much as possible sample transfer to avoid any contamination el into the HTC Introduce the TFM Teflon vess protection shield Add suitable reagents to the sample When part of the sample is left on the inner wall of the TFM Teflon vessel try to wet it by adding acids drop by drop Gently swirl the solution to homogenise the sample with the acid Place the TFM Teflon cover on the TFM Teflon vessel Push it by end and check that the cover fits well onto the vessel MDR technology Page 7 Place now the HTC adapter plate on the TFM Teflon cover with the flat part of it at facing downwards to have the space for the H
41. g action e many sulfates are insoluble Ba Sr Pb 350 10 300 8 250 F T w 200 7 8 B v 2 E Q WwW amp 150 p E TA E o 100 2 50 0 to 0 150 300 450 600 Time seconds The above graphic represents the temperature and pressure profile of sulfuric acid up on microwave heating Notice that temperature has been controlled at 300 C for 1 minute only without any pressure increase It is clear that the use of concentrated sulfuric acid in the MDR rotors poses significant problems because of its high boiling point 300 C are critical for TFM Teflon vessels and simply too high for PFA Teflon vessels they melt down at such temperature It is therefore advisable to use sulfuric acid only with a strict temperature control Acid digestion guidelines Page 4 1 7 PERCHLORIC ACID Perchloric acid has the following properties e boiling point is 203 C at 72 concentration e hot and concentrated is the strongest oxidizing acid e rapid sometimes explosive reaction with organic matrices e often mixed with nitric acid for a controllable digestion of organic matrices e all perchlorate are soluble with the exception of KCIO e perchloric acid decomposes at 245 C in a closed microwave vessel developing gaseous by products and a tremendous excess pressure WARNING Special care has to be taken when the use of perchloric acid is required Do not use at all perchloric acid with organic samples I
42. hed inside the vessels according with the sample preparation procedure applied It is therefore necessary to cool down the rotor before opening the vessels To facilitate this operating step Milestone has developed a cooling system able to reduce the cooling time to about 10 minutes Introduce the rotor body complete with vessels and protection ring inside the cooling system picture above the cover back on the cooling system itself and turn on the tap water MDR technology Page 11 Let the tap water flow in for approximately 10 15 minutes Turn off the water supply and move the rotor body from the cooling system to the work station preferably located under a fume hood Dry with the utmost care rotor and vessels prior uncapping Take the torque wrench and set the indicator to the OPEN position as shown in the next picture Place the rotor complete with vessels on the work station located under a fume hood Carefully loosen the screw in the upper part of the rotor body by using the tension wrench Open vessels very slowly since a certain pressure may still be present depending on sample type even if temperature is as low as room temperature Open the vessel opposite to your position as shown by the next picture Get a good control of the opening step rotating the torque wrench with wide angles Take the vessels out of the rotor body picture MDR technology Page 12 Carefully
43. hout any hardware modifications 1 2 8 PERFORMANCE THROUGH MODULARITY The ETHOS microwave platform has been designed with the microwave emission into the cavity from the back wall instead of the conventional position on top of the cavity This unique construction allows both the top and the bottom of the cavity to be free A free top allows the installation of batch reactors while the free bottom makes possible the installation of a continuous flow reactor or of an advanced magnetic stirring device The ETHOS microwave platform can be upgraded with suitable modules accessories to carry out acid digestion vacuum drying evaporation concentration protein peptide hydrolysis solvent extraction batch organic synthesis and continuous flow organic synthesis 1 2 9 DURABILITY THROUGH CORROSION RESISTANCE One of the key issues was assuring a long lifetime of our unit when performing digestions with aggressive acids HNO H SO HCl H PO HF The all stainless steel hardware undergoes a pretreatment sandblasting plus heat cycles to assure best bonding conditions between the Teflon coating and metal surfaces The microwave cavity the top cavity the door and even the external surface of the air inlet grid are plasma coated with 5 layers of Teflon applied at 350 C picture 1 2 10 DURABILITY THROUGH CHASSIS DESIGN The cabinet chassis is manufactured with magnetic 18 8 stainless steel 1 0mm gauge t
44. icrowave cavity is quite large to accommodate different types of accessories Dimensions are 35cm x 35cm x 35cm for a volume of approximately 43L The door is as standard feature made of stainless steel however on request ETHOS 1600 only it is possible to have a door with a high impact shock resistant 27cm x 27cm glass window for easy viewing of the illuminated cavity picture is manufactured with 18 8 stainless steel 1 5mm gauge picture 1 2 3 SAFETY THROUGH PATENTED DOOR DESIGN The door design is the most critical issue when developing new microwave hardware Mechanical strength and perfect sealing of the cavity to avoid microwave leaks are prerequisites Milestone s engineers on the basis of the movable door principle used in high pressure autoclaves designed a door with an innovative opening self resealing mechanism The door frame is mounted on four spring loaded high strength steel bars picture In the event of a sudden overpressure inside the cavity the entire door opens horizontally moves out presenting a large surface area for immediate and safe release of the overpressure Microwave power is instantaneously cut off Immediately afterward the door is pulled back by the springs resealing the cavity The microwave cavity door opens downwards to a flat horizontal position forming a stable work platform for handling microwave accessories before and after digestion procedures
45. igure at left represents a vessel in normal working conditions When pressure increases over the maximum spring working pressure figure in the center the entire cover is allowed to lift up because of the elastic deformation of the safety spring The overpressure is instantaneously released thanks to the large surface area The larger the surface area the shorter the time required to release the pressure Once the pressure inside the vessel has returned within the vessel limit the cover reseal the vessel permitting the operator to continue with the acid digestion without any loss figure at right This is the unique operating principle of the microwave digestion rotor technology of Milestone An indicator ring located next to the cover remains in the upper position in case of vessel venting The picture shows at left a vessel in normal conditions and at right a vessel after venting The Milestone Safety Guide Page 9 GUIDELINES FOR MICROWAVE ACID DIGESTION INTRODUCTION TO THE REAGENTS MOST COMMONLY USED IN MICROWAVE DIGESTION The acids used in microwave digestion may be classified in two main groups e nonoxidizing acids such as hydrochloric acid hydrofluoric acid phosphoric acid diluted sulfuric acid and diluted perchloric acid e oxidizing acids such as nitric acid hot concentrated perchloric acid concentrated sulfuric acid and hydrogen peroxide NITRIC ACID Nitric acid has the following properties e bo
46. iling point is 120 C at 65 concentration e poor oxidizing strength at concentrations less than 2M oxidizing strength increases with concentration and reaction temperature e most common acid for oxidation of organic matrices with this typical reaction CH x 2HNO gt CO g 2NO 2H O e it dissolves most metals forming soluble nitrates exceptions are Au and Pt not oxidated and Al B Cr Ti and Zr passivated e these metals require acid mixtures or diluted nitric acid e often mixed with H O HCl and H SO e available in high purity for trace level analysis 250 30 25 200 S 20 L 150 i p B o Ww 100 10 10 50 5 0 T T T T 0 0 300 600 900 1200 Time seconds The above graphic represents the temperature and pressure profile of nitric acid up on microwave heating Notice that pressure has been controlled at 25bar resulting in a temperature of 225 C The Milestone Safety Guide Page 10 HYDROGEN PEROXIDE Hydrogen peroxide is an oxidizing agent 2H O gt 2H O O added to nitric acid it reduces the nitrous vapours and it accelerates the digestion of organic samples by raising the temperature A typical mixture ratio is HNO H O 4 1 volume volume HYDROCHLORIC ACID Hydrochloric acid has the following properties boiling point of azeotropic mixture with H O with 20 4 HCl is 110 C available with 38 concentration it dissolves salts of weak acids carbon
47. lation time was preset the display shows immediately the above message To restart the program it is necessary to press the START key twice In case the microwave program is stopped by lowering the ETHOS 900 door handle the four built in switches are activated and the display shows DOOR NOT CLOSED Followed by CONTINUE CLOSE DOOR P 0 T1 0 T2 0 After closing the door the program starts again exactly where it had been interrupted whereas pressing STOP the display shows START RUNNING PRG 1 Press START to make the program start from the beginning Software mod lev 6 17 Page 15 1 10 SETUP Anytime whatever the message on the display obviously with the ETHOS 900 in stand by position it is possible to run the SETUP program by pressing the F6 key on the control terminal The display shows F1 SYSTEM F2 VALUES F3 BALANCE F4 PC Press the F1 key to visualize the SYSTEM sub menu the display shows DATE 30 03 1998 ENT OK Adjust the date if necessary by pressing the appropriate numbers on the keyboard then confirm by pressing the ENT key The display shows TIME 11 55 00 ENT OK Adjust the time if necessary by pressing the appropriate numbers on the keyboard then confirm by pressing the ENT key The display shows BALANCE TYPE 2 1 2 3 ENT OK Adjust the type of balance to be interface by pressing 1 2 or 3 Default value is 2 confirm by pressing
48. lon applied at 350 C picture DURABILITY THROUGH CHASSIS DESIGN The cabinet chassis is manufactured with magnetic 18 8 stainless steel 1 0mm gauge to act as a Faraday cage to eliminate potential interference to other instruments picture It is protected against acid organic solvent vapors through high temperature polymer coating on both the outside and inside surfaces The Milestone Safety Guide Page 6 ETHOS 900 SAFETY AND MONITORING CONTROL OPTIONS The ETHOS 900 microwave labstation can be fitted with any of the safety and monitoring control options below P N Description 33684 IRTC 500 Infrared temperature control 86300 APC 55E Automatic pressure control 33981 ATC 300 Automatic temperature control without sensor 33962 Temperature sensor model MW1Au gold plated 30009 SoftWAVE Method Development rev 2 0 requires PC not supplied The Milestone Safety Guide Page 7 MDR TECHNOLOGY Milestone patented microwave digestion rotor MDR technology provides analysts with unsurpassed performance capabilities and the highest standard of safety in closed vessel microwave digestion MDR rotors hold multiple microwave digestion vessels in a high strength one piece monobloc rotor body This unique design securely retains sample vessels during microwave digestion and subsequent venting of decomposition gases for maximum user safety The digestion vessels used in MDR rotors
49. m of the tank Carefully supply water and see that water slowly fills up the tank until the maximum level overflow is reached Adjust if required the water flow by using the valve of the water supply Let the rotor cool for at least 10 minutes during this time any water surplus will be drained by the overflow Check that the water is circulating around the rotor and that the level is below the indicator rings of the vessels by about 10mm Close the water inlet Take away the plexiglass cover and remove the rotor The drain 1 opens and in few seconds the tank will be completely empty Dry the rotor body with a tissue and place it on the work station MDR technology Page 4 1 6 MDR SAFETY The larger the surface area the shorter the time The above drawing clearly show the instantaneous release of overpressure due to the deformation of the HTC safety spring The figure at left represents a vessel in normal working conditions When pressure increases over the maximum spring working pressure figure in the center the entire cover is allowed to lift up because of the elastic deformation of the safety spring The overpressure is instantaneously released thanks to the large surface area required to release the pressure Once the pressure inside the vessel has returned within the vessel limit the cover reseal the vessel permitting the operator to continue with the acid digestion without any loss figure
50. microwave leakage protected inlet outlet connectors Temperature and pressure sensor connectors for vacuum and inert gas supply can be all easily installed without any hardware modifications PERFORMANCE THROUGH MODULARITY The ETHOS microwave platform has been designed with the microwave emission into the cavity from the back wall instead of the conventional position on top of the cavity This unique construction allows both the top and the bottom of the cavity to be free A free top allows the installation of batch reactors while the free bottom makes possible the installation of a continuous flow reactor or of an advanced magnetic stirring device The Milestone Safety Guide Page 5 The ETHOS microwave platform can be upgraded with suitable modules accessories to carry out acid digestion vacuum drying evaporation concentration protein peptide hydrolysis solvent extraction batch organic synthesis and continuous flow organic synthesis DURABILITY THROUGH CORROSION RESISTANCE One of the key issues was assuring a long lifetime of our unit when performing digestions with aggressive acids HNO H SO HCl H PO HF The all stainless steel hardware undergoes a pretreatment sandblasting plus heat cycles to assure best bonding conditions between the Teflon coating and metal surfaces The microwave cavity the top cavity the door and even the external surface of the air inlet grid are plasma coated with 5 layers of Tef
51. o act as a Faraday cage to eliminate potential interference to other instruments picture It is protected against acid organic solvent vapors through high temperature polymer coating on both the outside and inside surfaces ETHOS 900 Page 5 1 2 11 DURABILITY THROUGH ADVANCED EXHAUST COOLING SYSTEM This is another important factor for assuring long life of digestion vessels and safe working conditions The ETHOS platform is supplied with one two up on request heavy duty 5m minute exhaust fan placed above the cavity and installed separately from the electronics to eliminate the danger of acid corrosion of the electronics previous picture The air flow from the grids at the bottom of the cavity cools the external surfaces of the rotor and carries away any acid vapors released in the cavity An acid resistant flexible hose connects the exhaust fan to a fume hood assuring a safe working environment 1 2 12 DURABILITY THROUGH USER FRIENDLY SERVICE As perfection is not of this world easy access in case of servicing is a must Please refer to the separate ETHOS Service Manual for further information ETHOS 900 Page 6 1 3 ETHOS 900 SAFETY AND MONITORING CONTROL OPTIONS The ETHOS 900 microwave labstation can be fitted with any of the safety and monitoring control options below P N Description 33684 IRTC 500 Infrared temperature control 86300 APC 55E Automatic pressure control 33981 AT
52. ones and do proceed slowly until you hear a clicking sound informing that the vessel is properly closed inside its niche WARNING Stop turning the torque wrench when the click is heard In fact the torque wrench may overload the HTC safety spring if further rotation is applied MDR technology Page 9 Make slow 90 rotations with the torque wrench to get a better control of the correct closing of the vessel click sound The MDR 300 10S rotor is now ready to be introduced inside the ETHOS 900 1600 open the door of the microwave unit by pressing down the door handle picture Look at the position of the HTC drive adaptor of the ETHOS 900 1600 Press F7 on the control terminal keyboard to rotate the HTC drive adaptor until it reaches the position shown in the picture above with the flat side facing the ETHOS 900 1600 door Slide in the MDR 300 10S rotor inside the microwave cavity of the ETHOS 900 1600 Notice the position of the black coloured dot on the polypropylene rotor body facing the door of the microwave unit In this way the rotor is perfectly aligned with the HTC drive adaptor MDR technology Page 10 Close the door of the ETHOS 900 1600 picture Switch on the ETHOS 900 1600 picture Start a suitable microwave acid digestion program 1 7 4 COOLING DOWN AND UNCAPPING THE VESSEL Once the digestion program is completed high temperature and pressure are reac
53. ot on the selection knurl A MDR technology Page 3 1 5 4 COOLING SYSTEM The cooling system P N 40014 can accomodate every kind of monobloc rotors Its design allows a continuous tangential water circulation and exchange inside the container therefore permitting a very rapid cooling of the rotor The complete cooling system includes the following items drawing INLET DRAIN idi ifi DRAIN i pay e Polypropylene bottom plate 1 e Plexiglass transparent container 2 e Water inlet complete with junction 3 e Water outlet for drain 4 e Outlet junction for drain 5 e Plexiglass protection cover 6 e Overflow control device 7 1 5 5 COOLING SYSTEM INSTALLATION AND OPERATION To install the cooling system simply follow the procedure below 1 Unpack the cooling system 2 Connect it to the water supply junction diameter is 1 2 3 Place the cooling system near the ETHOS 900 1600 and next to a water supply and a water drain 4 Connect with rubber hose the inlet 3 to the water supply which must be provided with a suitable valve 5 Connect the drain 5 to the laboratory drain The cooling system is ready for operation After the microwave digestion take the rotor out of the unit and place it inside the cooling tank after removing the plexiglass cover of the system Relocate the plexiglass cover in its position The bottom of the rotor closes the drain at the botto
54. oxidizing strong complexing nature e used in digestion of minerals ores soils rocks and even vegetables containing silicates e major use is the decomposition of silicates according with this reaction SiO 6HF gt H SiF 2H O e often used in combination with HNO or HCIO 1 5 2 EVAPORATION CONCENTRATION e Following dissolution many analyses require removal of HF to prevent equipment damage or to resolubilize insoluble fluorides e many analytes such as As B Se Sb Hg and Cr may volatilize 1 5 3 COMPLEXATION e Alternative approach to remove HF from the solution by addition of Boric acid e the following reactions take place H 3BO 3HF gt HBF OH 2H O and HBF OH HF gt HBF H20 e 10 50 times excess Boric acid enhances reaction rate 250 30 25 200 S 20 L 150 i p B o Ww 100 13 FE 10 50 5 0 T T T E 0 0 300 600 900 1200 Time seconds The above graphic represents the temperature and pressure profile of hydrofluoric acid up on microwave heating Notice that pressure has been controlled at 25bar resulting in a temperature of 240 C Acid digestion guidelines Page 3 1 6 SULFURIC ACID Sulfuric acid has the following properties e boiling point is 340 C at 98 concentration exceeding the maximum working temperature of TFM Teflon vessels e careful reaction monitoring is required to prevent vessel damages e it destroys organics by dehydratin
55. ple program requires only 3 steps To skip step 4 through step 10 simply press ENT on the keyboard The display will show ROTOR CTRL OFF 1 MODE 1 ON OFF ENT OK Standard setting is ROTOR CTRL OFF This function may be set ON when the optional IRTC 500 Infra Red Temperature Control device is installed in the ETHOS 900 Press the key MODE 1 to switch the function to ON then confirm by pressing ENT on the keyboard The display will now show TIME AT TEMPERATURE 1 0FF 1 MODE 1 ON OFF ENT OK Standard setting is TIME AT TEMPERATURE OFF Software mod lev 6 17 Page 4 The TIME AT TEMPERATURE function may be used when the ETHOS 900 is supplied with an optional ATC 300 Automatic Temperature Control device It allows to hold preset temperature values for preset times Press the key ENT if an ATC 300 is not installed in the ETHOS 900 or if the TIME AT TEMPERATURE function is not required By pressing the key MODE 1 the TIME AT TEMPERATURE function is activated In the latter case the microwave program will be composed by e ramping steps step 1 3 5 7 and 9 e holding steps step 2 4 6 8 and 10 The diagram below better explains the TIME AT TEMPERATURE function Step Time hh mm ss Power Watt Pressure bar Temp 1 C Temp 2 C 1 00 05 00 500 0 60 0 2 00 05 00 500 0 60
56. pressure and will safely vent when a buildup of decomposition gases in excess of vessel s maximum operating pressure is reached Microwave digestion of organic samples frequently involves exothermic reactions which instantaneously generate large amount of decomposition gasese CO and NOx as the sample is oxidized For proper overpressurization protection of microwave digestion vessels the venting capacity of the relief device must be equal or higher than the rate of decomposition gas formation Only Milestone s relief valve is capable of instantaneously venting excess decomposition gases and resealing the vessel for completation of the digestion procedure The digested sample is retained inside the vessel for analysis 1 1 MONOBLOC MDR ROTORS Rotor MDR 300 10S P N 41100 Vessels 10 Vessel material PFA Teflon Maximum pressure 30bar Maximum temperature 240 C Rotor MDR 300 10S P N 41200 Vessels 10 Vessel material TFM Teflon Maximum pressure 30bar Maximum temperature 240 C Rotor MDR 1000 6S P N 35301 Vessels 6 Vessel material TEM Teflon Maximum pressure 100bar Maximum temperature 300 C 1 22 SEGMENTED MDR ROTORS Rotor MPR 300 12S P N 35180 Vessels 12 Vessel material PFA Teflon Maximum pressure 30bar Maximum temperature 240 C Rotor HPR 1000 10S P N 35100 Vessels 10 Vessel mate
57. ready to be introduced inside the ETHOS 900 1600 open the door of the microwave unit by pressing down the door handle picture MDR technology Page 18 Close the door of the ETHOS 900 1600 picture Switch on the ETHOS 900 1600 picture and start a suitable microwave acid digestion program MDR technology Page 19 1 8 4 COOLING DOWN AND UNCAPPING THE VESSEL Once the digestion program is completed high temperature and pressure are reached inside the vessels according with the sample preparation procedure applied It is therefore necessary to cool down the rotor before opening the vessels To facilitate this operating step Milestone has developed a cooling system able to reduce the cooling time to about 10 minutes Introduce the rotor body complete with vessels and protection ring inside the cooling system picture above Put the cover back on the cooling system itself picture Turn on the water supply and let the water flow in for approximately 10 15 minutes picture Turn off the water supply and move the rotor body from the cooling system to the work station preferably located under a fume hood Dry with the utmost care rotor and vessels prior uncapping Take the torque wrench and set the indicator to the OPEN position as shown in the next picture Place the rotor complete with vessels on the work station located under a fume hood Carefully loosen the screw in the upper pa
58. rial TFM Teflon Maximum pressure 100bar Maximum temperature 300 C MDR technology Page 1 1 3 MDR MAJOR COMPONENTS Compression screw ____ Safety spring Adapter plate Indicator ring Vessel Safety shield Rotor body The rotor consists of a high density polypropylene core in which a number of niches have been carved along the periphery by a numerical control machining center The compact core has the required strength to withstand the extreme pressure generated inside the vessel during digestion The core tolerates this pressure without any deformation and therefore with high safety Special plastic compression screws are located on the top of the rotor next to each niche Suitable pressure is applied to the dome shaped spring holding the cover to the top of the vessel by tightening the screws to the appropriate degree The dome shaped flat top spring is the heart of the MDR technology and is made of HTC a new high performance plastic HTC is crystalline and can act as a powerful and very reliable spring The adapter plate is placed on top of the cover Made of a plastic with high resistance to mechanical compression it allows a very homogeneous and repeatable distribution of the preset pressure limit The cover has a flat bottom rim and perfectly fits the top rim of the vessel Sealing between cover and vessel takes place on a very large surface area
59. rt of the rotor body by using the tension wrench Open vessels very slowly since a certain pressure may still be present depending on sample type even if temperature is as low as room temperature Open the vessel opposite to your position as shown by the next two pictures Get a good control of the opening step rotating the torque wrench with wide angles MDR technology Page 20 Take the vessels out of the rotor body picture Carefully take up the vessel cover together with the TFM Teflon protection ring picture Rinse the lower part of the TFM Teflon cover with distilled water collecting the same inside the vessel picture MDR technology Page 21 Slide the TFM Teflon vessel out of the HTC protection shield picture Pour the solution in a laboratory volumetric flask washing repeatedly the TFM Teflon vessel with distilled water picture Repeat the same operation with all vessels in the rotor Your samples are now ready to be analysed MDR technology Page 22 1 9 MDR ROTORS MAINTENANCE As general rules e do not use any organic solvent to clean or dry any part of the rotor with the exception of the TFM Teflon covers and of the TFM or PFA Teflon vessels e Dry every component including the vessels thoroughly with paper towel or cloth before placing the rotor in the microwave unit Any moisture or acid trace would heat up in the microwave field and it could possibly damage the compon
60. s rich in carbohydrates wheat sugar etc at 150 C or higher for samples rich in proteins serum albumin etc and at 170 C or higher for fatty samples cheese butter vegetable oil etc Those temperature represent minimum target digestion temperature for the above matrices The sample amount directly influence the pressure generated inside the vessel as sample is decomposed into CO gas Therefore some limitation in regards to the sample amount may apply Follow the scheme below Organic samples Fat content lt 75 Weight lt 0 5g Weight lt ig Weight lt 0 25g Weight lt 0 5g MDR 1000 6S MDR 1000 6 Note that the above sample amounts do refer to organic matter Therefore the moisture content of the sample should not be considered for instance if a sample contains about 80 of moisture up to 5 gram could be digested When operating the ETHOS 900 without ATC 300 Automatic Temperature Control follow the basic programs recommended by Milestone Microwave power and heating time strictly depend on the number of samples being prepared simultaneously To organic samples 4 8mL of nitric acid depending on sample amount should be added as well as 1 2mL of hydrogen peroxide Fat content gt 7 5 Acid digestion guidelines Page 6 2 1 BASIC PROGRAM FOR 3 SAMPLES Step Time minutes Power Watt 1 5 250 2 3 600 3 2 300 2 2 BASIC PROGRAM FOR 6 SAMPLES Step Time
61. should be connected to the fume hood by using the hose supplied details will follow WARNING The weight of the ETHOS 900 is approximately 85kg At least 3 persons should remove the system from its box and locate it on the bench Open now the boxes containing the accessories of the ETHOS 900 Notice the ETHOS 900 power cord picture ETHOS 900 Page 9 Notice the plastic hose 2ml long picture s pigiama Notice also the control terminal model 240 with its interface cable 50 pins picture ETHOS 900 Page 10 1 5 2 ETHOS 900 OVERVIEW Notice some of the most important details of the ETHOS 900 Main swicth picture WARNING During the ETHOS 900 installation the main switch should be in the OFF position WARNING During the ETHOS 900 installation both the switches should be in the OFF position Exhaust module main switches picture The ETHOS 900 comes with one exhaust module as standard feauture Optionally it is possible to install a second exhaust module The VENT 1 swicth refers to the exhaust module built in as standard feature while the VENT 2 swicth refer to the second optional exhaust module Note the two openings at the side of the ETHOS 900 picture Those are the air inlets for the air exhaust system located in the upper part of the system Not to be worry about microwave leakages A metal grit which can
62. t may be possible to use perchloric acid with inorganic samples when the temperature does not exceed 200 C and when the amount of perchloric acid is below 20 volume volume of the total solution volume 1 8 AQUA REGIA Aqua regia properties are the following e made up by hydrochloric acid and nitric acid in a 3 1 volume volume mixture e it produces NOCI nitrosyl chloride which decomposes in NO and Cl up on heating e it dissolves precious metals e it must be freshly prepared and used immediately otherwise it evolves chlorine gas overpressurizing and venting the vessel 250 30 4 95 200 S 20 L 150 v g 100 10 50 45 0 T T T 0 0 300 600 900 1200 Time seconds The above graphic represents the temperature and pressure profile of aqua regia up on microwave heating Notice that pressure has been controlled at 25bar resulting in a temperature of 200 C Acid digestion guidelines Page 5 Pressure bar 2 0 MICROWAVE ACID DIGESTION OF ORGANIC SAMPLES Organic samples group includes food feed tissues botanicals biological etc Nitric acid is the most common oxidizing agent used to digest organic samples according to the following reaction ORG HNO gt NOx CO H O Metals are converted into soluble nitrates available for analysis When operating the ETHOS 900 with ATC 300 Automatic Temperature Control device set the digestion temperature at 140 C or higher for sample
63. t reduces the nitrous vapours and it accelerates the digestion of organic samples by raising the temperature A typical mixture ratio is HNO H O 4 1 volume volume 1 4 HYDROCHLORIC ACID Hydrochloric acid has the following properties boiling point of azeotropic mixture with H O with 20 4 HCl is 110 C available with 38 concentration it dissolves salts of weak acids carbonates phosphates and most metals are soluble with the exception of AgCl HgCl and TiCl excess of HCl improves the solubility of AgCl converted into AgCl strong complexing nature widely used for iron based alloys because of its ability to hold large amounts of chloro complex in solution other complexes formed are Ag I Au II Hg I1 Ga IID Tl D Sn IV Fe ID and Fe IID it does not dissolve oxides of Al Be Cr Ti Zr Sn and Sb sulphates of Ba and Pb group II fluorides SiO TiO and ZrO 250 30 25 200 S 20 L 150 5 p 3 fa 15 5 Q Ww 100 13 10 50 5 0 T T T T 0 0 300 600 900 1200 Time seconds The graphic above represents the temperature and pressure profile of hydrochloric acid up on microwave heating Notice that pressure has been controlled at 25bar resulting in a temperature of 205 C Acid digestion guidelines Page 2 1 5 HYDROFLUORIC ACID Hydrochloric acid has the following properties 1 5 1 ACID DIGESTION e Boiling point is 108 C at 40 concentration e non
64. take up the vessel cover together with the TFM Teflon protection ring picture Rinse the lower part of the TFM Teflon cover with distilled water collecting the same inside the vessel picture Slide the TFM Teflon vessel out of the HTC protection shield picture Pour the solution in a laboratory volumetric flask washing repeatedly the TFM Teflon vessel with distilled water picture Repeat the same operation with all vessels in the rotor Your samples are now ready to be analysed MDR technology Page 13 1 8 MDR 1000 6S The MDR 1000 6S high pressure rotor contains 6 vessels for acid digestion of routine and difficult samples at operating pressure up to 100bar 1 450psi 1 8 1 MDR 1000 6S SETUP The MDR 1000 6S has P N 35301 and it is composed by the following items P N Quantity Description 35320 1 Rotor body 34010 6 Safety spring 34019 6 Adapter plate 34043 6 TEM Teflon cover 34056 6 Indicator ring 34040 6 TEM Teflon vessel 34048 6 Safety shield MDR technology Page 14 1 8 2 HOW TO OPERATE WITH THE MDR 1000 6S ROTOR 1 8 3 SAMPLE WEIGHING REAGENTS ADDITION AND VESSEL CAPPING Place a TFM Teflon vessel directly on the balance plate The weight of the TFM Teflon vessel is about 120g therefore most analytical balances may be used for the pourpose picture Tare the vessel and directly weigh the sample by placing it inside
65. ternal temperature up to 120 C can be set starting from which the microwave emission will be controlled 1 8 5 ROTOR CONTROL Rotor control ON OFF When operating with an IRTC 500 if rotor control is set ON then the infrared sensor will read the highest value out of a complete turn of the rotor This value will be used for controlling the microwave output emission 1 8 6 TWIST The twist function must be activated in case of pressure and internal temperature control in the reaction vessels A 360 alternate rotation of the MDRs is activated to avoid bending of the sensor connections In case the twist function is off the unit presents no alternate rotation and before program running the following message will appear TWIST NOT READY and POWER IS OFP 1 8 7 VENTILATION Insert the ventilation time to cool down the vessels prior water cooling Software mod lev 6 17 Page 13 1 9 HOW TO USE A PREVIOUSLY STORED PROGRAM Switch on the ETHOS 900 and the display will show alternatively the two following messages MultiQUANT SW V 6 01 M10 1d77 After a few seconds the display will show FI WORK F2 EDIT F3 READIN F4 READOUT Press the F1 key to activate the WORK function the display shows WORK PROGRAM 1 1 20 ENT OK Select the number corresponding to the program to be used for instance 1 Confirm the choice of program number by pressing the ENT key and the display
66. the ENT key and the display shows PULSE WIDTH 50 10s 1 50 ENT OK The ETHOS 900 operate with unpulsed emission of microwave at 250 Watt When other power levels are selected then a pulsed mode is used The standard setting for pulse width is 10 10s equal to 1 second Microwave power is therefore regulated with alternate ON OFF microwave emission with duty cycles of 1 seconds as for the following examples e 450Watt is equal to 0 5 seconds of magnetron ON and 0 5 seconds of magnetron OFF e 90Watt is equal to 0 1 seconds of magnetron ON and 0 9 seconds of magnetron OFF If the operator select a pulse width of 50 10s equal to 5 seconds then the following table will apply e 450Watt is equal to 2 5 seconds of magnetron ON and 2 5 seconds of magnetron OFF e 90Watt is equal to 0 5 seconds of magnetron ON and 4 5 seconds of magnetron OFF Confirm the choice of pulse width by pressing the ENT key and the display shows TWIST CHECK ON MODE1 OFF ENT OK This function enables the electronic check of the twist function Default mode is ON Press the key MODE1 to disable the function it is however recommended to leave it ON when the APC and or the ATC sensors are installed Press the key ENT to confirm and the display shows GAS SENSOR OFF Software mod lev 6 17 Page 16 MODE1 SELECT 0 ENT OK If a gas sensor is installed in the ETHOS 900 it can be activated with this section of
67. the vessel picture Try to reduce as much as possible sample transfer to avoid any contamination Introduce the TFM Teflon vessel into the HTC protection shield WARNING The wall surfaces of the HTC protection shield as well as the outer wall of the TFM Teflon vessel must be dry and clean Damages may occour otherwise MDR technology Page 15 Add suitable reagents to the sample Locate the HTC safety spring onto the HTC adapter When part of the sample is left on the inner wall of plate picture the TFM Teflon vessel try to wet it by adding acids drop by drop picture Place the TFM Teflon indicator ring on the cover Gently swirl the solution to homogenise the sample and push it down completely until it fits the groove with the acid of the HTC safety shield as shown by the next Place the TFM Teflon cover on the TFM Teflon picture vessel Push it by end and check that the cover fits well onto the vessel picture Position the polypropylene rotor body on the work station picture Place now the HTC adapter plate on the TFM Teflon cover with the flat part of it at facing downwards to have the space for the HTC safety on the top side picture MDR technology Page 16 Introduce the vessel vertically into one of the numbered niches carved along the periphery of the 6 position polypropylene rotor body Notice the position of the venting hole located in the TFM Teflon indicator ring
68. ype nor a commercially modified kitchen microwave unit it is a rugged heavy duty professional system designed to guarantee years and years of trouble free and safe operation The microwave cavity is quite large to accommodate different types of accessories Dimensions are 35cm x 35cm x 35cm for a volume of approximately 43L As a standard feature the door is made of stainless steel however on request ETHOS 1600 only it is possible to install a door with a high impact shock resistant 27cm x 27cm glass window for easy viewing of the illuminated cavity picture The hardware is manufactured with 18 8 stainless steel 1 5mm gauge picture SAFETY THROUGH PATENTED DOOR DESIGN The door design is the most critical issue when developing new microwave hardware Mechanical strength and perfect sealing of the cavity to avoid microwave leaks are prerequisites Milestone s engineers on the basis of the movable door principle used in high pressure autoclaves designed a door with an innovative opening self resealing mechanism The door frame is mounted on four spring loaded high strength steel bars picture In the event of a sudden overpressure inside the cavity the entire door opens horizontally moves out presenting a large surface area for immediate and safe release of the overpressure Microwave power is instantaneously cut off Immediately afterward the door is pulled back by the springs resealing the cavity

1.0 ethos 900 1.1 introduction 1.2 technical specifications

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