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1. Accumet Benchtop Meters pH mV lon Conductivity AR50 AR25 AR20 Advanced technology makes simple accurate versatile Exceptional ease of use clear language prompts HELP screens and error messages guide you through the measurement process Large easy to read LCD readouts with reliable proven touchscreen technology responds to a light tap even with gloves or a pencil Easily customizable screens let you display only the data you want and need Two series of meters Basic and Research Models to suit your requirements Fishers family of Accumet Benchtops has been completely redesigned Now they re not only accurate and versatile but also the easiest to use most user friendly pH mV ion conductivity meters you can buy From their sleek compact design to their oversize LCD readouts to their innova tive highly reliable touchscreen technology Research Models only Accumet Benchtop Meters put a wealth of information at your fingertips Just look at what they offer you Standardization is ultra simple otandardizing Accumet Benchtop Meters is so simple a child can do it Here s all you do Table of Contents 1 Press STANDARDIZE to enter the standardi zation mode 2 Press STANDARDIZE again to perform the standardization Thats all there is to it In response to your commands the meter automatically recognizes the buffer adjusts the buffer value for temperature waits for a stable read
2. 13 620 289 Ag AgCl Reference Agar Paper 13 620 104 Polypropylene Body gelled 0 14 5 80 106 10 General Purpose 13 620 108 Ag AgCl Reference Field Plant Use 13 620 252 Epoxy Body Pencil Thin 0 14 5 80 178 6 Tall Flasks Bottles 13 620 290 gelled Ag AgCl Reference 13 620 283 Polypropylene Body 0 14 5 80 106 10 General Purpose 13 620 299 Double Junction Ag AgCI Tris Paper Pulp 13 620 AP2 pH ATC Polypropylene Body 0 14 5 80 106 10 Field Use Double Junction Ag AgCI 13 620 111 pH ATC Epoxy Body 0 14 5 80 106 10 Field Use 13 620 112 Double Junction Ag AgCl With U S Standard connector and Pin connector on combinations With BNC connector With BNC and Mini Phone ATC connectors With BNC and 7 Phone ATC connectors With Twist Lock waterproof connector Catalog No 13 620 755 13 620 758 13 620 759 13 620 AP20 13 620 AP52 13 620 AP51 13 620 AP50 13 620 186 13 620 187 13 620 3 13 620 284 13 620 256 13 620 294 13 620 1 13 620 295 13 620 51 13 620 52 13 620 79 13 620 57 13 620 62 13 620 61 13 620 258 13 620 259 13 620 53 13 620 273 13 620 46 13 620 47 13 620 45 13 620 115 13 620 122 13 620 149 13 620 123 13 620 82 13 620 81 Description pH ATC Nonglass pH ATC Nonglass Adapter 13 620 758 to BNC pH ATC Nonglass pH ATC Epoxy Body gelled Ag AgCl Double Junction pH A
3. 3 to 8pH 108 x 13 0 to 80 C 2 to 12pH 102 x 13 0 to 80 C 2 to 12pH 108 x 13 0 to 80 C 0 to 50 C 4 5pH 108 x 18 0 to 50 C 0 to 14pH 0 to 80 C 102 x 13 0 to 14pH 114 x 13 0 to 60 C Typical Applications Foods beverages soil pharmaceuticals explo Sives fertilizers plants EDTA titration endpoint Pollution testing foods pharmaceuticals explo sives fertilizers plants meats pickling baths Body fluids soils sew age fertilizers foods beverages Biological fluids soil plants water effluents foods Method ASTM approved Water wastewater soil dairy tomato vegetable products meats Meth od ASTM AOAC approved Plating baths natural water silicon Petrochemical plating water wastes Water wastewater stack gases explosives etch ing baths bioresearch beverages detergents Method ASTM EPA approved Organic compounds biological samples water wastewater Water pulping liquors water industrial waste stack gases food ferti lizers Method ASTM EPA approved Measures carbon di oxide carbonate bicar bonate in beverages wines ground sea water Meats fish dairy pro ducts fruit juices brewing water ground water sea water soils bodily fluids 5 x 107 to 107 Volatile amines 13pH 108 x 18 Sewage effluent boiler ES 23 Catalog No Accumet Annular Junction Reference Half Cells For SEs Description pH
4. AR50 Meter Kit includes meter Ag AgC combination pH electrode ATC probe Catalog No 13 636 AR50 electrode support arm and bracket user manual and power supply AR50B Meter Kit 13 636 AR50B includes meter AccuTupH rugged bulb calomel combination pH electrode for Tris buffer applications ATC probe electrode support arm and bracket user manual and power supply AR50A Meter only 13 636 AR50A includes meter electrode support arm and bracket user manual and power supply The Accumet Research Model AR25 pH mV lon Meter Powerful measure pH and ion simultaneously e Intuitive user interface makes it exceptionally easy to use e Extra large scratch and chemical resistant LCD readout with dual display e Reliable touchscreen technology responds to a light tap of your finger e Automatically corrects for tempera ture fluctuations with separate ATC probe in each channel e Data acquisition via bidirectional communication with computer or printer e Multiple language option English German French and Spanish built in Uses standard glass or an AccuFet electrode with no adapter required The Accumet AR25 Meter is fully equipped for the most demanding pH and ion measurements yet is so simple to use almost anyone can do it It offers Accumet accuracy and reliability plus innovative dependable touchscreen technology proven in thousands of applications worldwide Its user friendly
5. Cs NH TF AY Ag Tris Li Na I CN S S5 F CN high levels of Cl NHs BE E ON S OH 9 GN OR Br Ag Hg CF Br Fe Cd Ag Hg CF Br Fe Cd GE Br E S absent OH OH Ag Hg Cur Cd Fe Ag Hg Cir Cd re Hi Hg 0 01 to 107 900 Ag 0 003 to 32 100 S7 Accumet Gas Sensing lon Selective Electrodes 13 620 504 13 620 505 13 620 506 13 620 507 Ammonia Combination Epoxy Body Carbon Dioxide Combi nation Epoxy Body 0 009 to 1700 10 to 3 x 10 0 440 to 1320 Accumet Glass Membrane lon Selective Electrodes 13 620 500 13 620 501 13 620 502 13 620 503 sodium Half Cell Glass Body Sodium Combination Epoxy Body 10 to 10 0 023 to 23 000 10 to 10 0 023 to 23 000 metal cations that complex ammonia Volatile organ ic acids Ag Li Kt NH Ag Li Kt NH With U S Standard connector and Pin connector on combinations With BNC connector pH Temp Range 3 to 10pH 102 x 13 0 to 40 C 2 5 to 11pH 102 x 13 0 to 40 C 2 5 to 11pH 102 x 13 0 to 40 C 0 to 14pH 102 x 13 0 to 100 C 2 to 14pH 108 x 13 0 to 80 C 0 to 14pH 102 x 13 0 to 100 C 2 to 12pH 108 x 13 0 to 80 C 2 to 12pH 102 x 13 0 to 80 C 2 to 12pH 108 x 13 0 to 80 C 11 to 13pH 102 x 13 0 to 80 C 5 to 9pH 102 x 13 0 to 80 C 5 to 8pH 108 x 13 0 to 80 C 3 to 8pH 1025 13 0 to 80 C
6. The choice in most applications is between calomel Hg Hg2Cl and silver silver chloride Ag AgCl elements Selection is based primarily on sample temperature but the effects of the electrolyte solution on the sample should also be considered e Calomel mercury mercurous chloride internals are recommended for most routine applications The electrolyte is a saturated solution of potassium chloride KCl so they re easy to use and maintain Typical tempera ture range is 5 to 80 C e Silver silver chloride internals have a wider temperature range of 5 to 100 or 110 C The electrolyte is 4M KCI saturated with AgCI to prevent dissolution of the silver chloride portion of the internal element Though Ag AgCl internals are usable at higher temperatures the presence of AgCI in the electrolyte may cause junc tion clogging with low conductivity samples and certain silver sensitive samples such as biomed ical specimens can react with the electrolyte causing additional measuring difficulties Double junction Ag AgCl electrodes are available to pre vent sample contamination by heavy metals and reduce junction clogging as well See pp 22 and 23 for Accumet reference electrodes The Combination Electrode Reference Electrode outer body Porous Junction pH ee Electrode Glass Membrane inner body The combination electrode contains both pH sensing and reference half cells joined in a single bod
7. When ionic strength is held constant the Nernst Equation reduces to E E 23 8I log C where C is the concentration of the ion of interest This form of the Nernst Equation states that the electrode potential varies directly with the log of the concentra tion in a straight line manner The slope of the line is equal to the value of RT 2 3 F The table below gives theoretical slope values at 25 C Species Slope mV decade Monovalent cation 59 16 Monovalent anion 59 16 Divalent cation 429 58 Divalent anion 29 58 The equation is as follows _93 RI Ded WE where S is the electrodes slope The Nernst Equation thus reduces to E E S log C ISE Analysis Methods Direct Analysis Although this method is called direct some sample preparation is usually needed Normally an ionic strength adjuster and or pH adjuster must be added to samples and standards Then stan dards are used to calibrate a meter or to construct a calibration curve by plotting the electrode s output in mV vs the log of concentration Sample concentration is then read directly from the meter or calibration curve Incremental Methods These procedures can reduce errors caused by temperature variations complex matri ces and complexation They re also useful for applica tions where only occasional samples are analyzed Incremental methods include 1 Known Addition 2 Known Subtraction 3 Analate Addition and 4 Analate Sub
8. Yes Output on stable time manual 1 to 9 999 sec Yes 2 000 to 20 000 0 1 0 01 0 001 30 002 Yes 5 1800 0 0 1 0 1 0 1 1 0 10 0 to 3 x 10 uS em 30megohm cm to 100megohm cm 2 to 42ppt 0 5 5 0 to 105 0 C OIC 0 2 C BNC Pin ATC 2 pin conductivity bidirectional RS 232 2 DIN for FET and 4 cell conductivity 6 W x 9 L x 3 5 H 165 x 235 x 89mm 2 34 Ib 1 1kg Catalog No 13 636 AR20 includes meter Ag AgC combination pH electrode ATC probe electrode support arm and bracket user manual and power supply AR20B Meter Kit 13 636 AR20B includes meter AcculupH rugged bulb Accu e pHast combination pH electrode for Tris buffer applications ATC probe electrode support arm and bracket user manual and power supply AR20A Meter only 13 636 AR20A includes meter electrode support arm and bracket user manual and power supply The Accumet Research Model ARTS pH mV C Meter uis B a A SOM eem i _ T i Large scratch and chemical resistant LCD readout with reliable touchscreen technology for ease of operation Intuitive operation with on screen plain language prompts and HELP screens that guide you through the measurement process Data acquisition via bidirectional communication with computer or printer e Multiple language option English German French or Spanish built in The Accumet AR15 Meter measures pH and mV w
9. ing enters the data verifies proper electrode perform ance and calibrates the meter Throw away your user manual We d certainly never advise you to do it But Accumet Benchtop Meters are so easy to use you probably could Accumet Benchtop Meters feature simple intu itive operation on screen operational prompts and context specific HELP screens Accumet Research Models only designed to guide you through the meter s operation in plain easily understandable language Plus not only are Accumet Benchtop Meters accu rate versatile and easy to use they re backed by a full two year warranty Should any Accumet Meter fail to perform to specification under normal use during the first two years it will be repaired or replaced at no charge Easily customize screens and measurement modes to match your requirements There are two ways to customize the screens and meas urement modes on Accumet Benchtop Meters Choosing the System Setup Options menu on AR15 Research Model Meters lets you customize the screen display to show exactly the parameters that suit your needs You can edit the date screen configuration time beeper status and print configuration Customizing within each meter s operational modes pH mV ion conductivity lets you select appropriate operating parameters resolution buffer sets and similar settings different for each operating mode to match your requirements You can also choose either
10. power supply AR25B Meter Kit 13 636 AR25B includes meter AcculupH rugged bulb Accu pHast combination pH electrode for Tris buffer applications ATC probe electrode support arm and bracket user manual and and power supply AR25A Meter only 13 636 AR25A includes meter electrode support arm and bracket user manual and power supply The Accumet Research Model AR2O pH mV Conductivity Meter e Large easy to use LCD touchscreen displays information clearly e Exceptional user interface with plain language prompts make it a breeze to use e Select from two procedural levels to suit your needs Accepts 2 cell and 4 cell conductivity probes Built in replatinizing circuit e Automatically corrects for tempera ture fluctuations with ATC probe Data acquisition via bidirectional communication with computer or printer e Multiple language option English German French or Spanish built in The newly designed Accumet AR20 s powerful conductivity and pH modes provide the same performance and ease of use as our top of the line AR5O You also get the convenience and benefits of our extra large touchscreen technol ogy with an unequaled range of user determined setup screen display data storage and printing options Features e The largest display available yet com pact design saves valuable bench space e On screen prompts in plain language and context specific HELP screens easi ly
11. compensate for electrode output varia tions most meters are equipped with a slope or effi ciency control to adjust the meter to match electrode voltage exactly Microprocessor based meters are pro grammed to solve the Nernst equation taking into account electrode voltage efficiency and temperature Most provide automatic buffer recognition and stan dardization as well as user prompting error messages and diagnostic circuitry to simplify operation and reduce error Standardization Buffers Buffers solutions of known pH value adjust the system to display accurate measurements Buffers are available as ready to use or concentrated solutions in capsules and as prepackaged salts All have the special characteristic of resisting pH change upon dilution or acid base contamination For best accuracy a two point standardization is per formed first with a buffer value close to the electrode systems zero potential typically pH 7 and next with an acid or base buffer whose value brackets the expect ed pH value of the sample Microprocessor based meters may permit additional calibrations up to five points in some models for increased definition of electrode slope allowing measurement of samples with widely varying pH values For best accuracy all buffers should be at the same temperature as the sample The following table lists three buffers established by the National Institute of Standards and Technology with their pH val
12. design gives you an unparal leled range of user determined setup screen display data storage and printing options Its dual channel design is like having two meters in one You can display one channel at a time or toggle to split screen for simultaneous viewing For the lab that needs the versatility of a research grade pH meter and an ion meter it s an easy choice Features e The largest display available yet com pact design saves valuable bench space e User prompts and context specific HELP screens easily guide user through operation e Extensive setup screens allow you to customize the meter to your needs e Autocalibrates with up to 5 pH buffers from any of 3 standard sets and 15 different buffers also accepts custom buffers and manual calibration e Innovative touchscreen makes it versatile and easy to use e Dual channel meter allows you to measure two parameters at once and view results from both channels on screen simultaneously e Reads pH to 0 001 mV to 0 1 e Reads ISE in ppm mg ml and mole L e Direct and indirect ISE measurements including known addition and subtraction and analate addition and subtraction methods e Extensive GLP capabilities with customiz able printer or computer output and 250 reading datalog capability e Print setup allows you to print exactly what you want when you want it not just a screen dump e Time can be displayed in 12 or 24 hour format and date ca
13. guide user through operation e Autocalibrates with up to 5 pH buffers from any of 3 standard sets and 15 different buffers also accepts custom buffers and manual calibration e Innovative touchscreen makes it versatile and easy to use e Reads pH to 0 001 mV to 0 1 plus con ductivity resistivity salinity and TDS e Extensive CLP capabilities with customiz able printer or computer output and 250 reading datalog capability e Autoranging capability e Print setup allows you to print exactly what you want when you want not just a screen dump e Time can be displayed in 12 or 24 hour format date can be displayed in U S or international formats e Accepts standard glass electrode or an AccuFet electrode directly no need for an adapter mV and conductivity readout Same accuracy as our top model pH Specifications and Ordering Information Displays Screen size Measurement display height Temp etc display height Memory Internal diagnostics Programmable data output Print interval Programmable alarm pH mode Range Resolution Relative accuracy Auto manual buffer recognition Calibration points mV mode Range Resolution Accuracy Conductivity mode Cell constants Ranges Conductivity Resistivity salinity Accuracy Temperature mode Range Resolution Accuracy Inputs outputs Meter size Meter weight Description AR20 Meter Kit 640 x 480 LCD AW x 6 H PAS ve 250 data points
14. of two procedural levels Basic Level displays a reduced set of information and restricts user access to a limited list of setup parame ters Advanced Level allows user configurable output and access to all setup parameters Using this feature enables scientists to configure the meter in Advanced Level and have a technician perform measurements in Basic Level limiting the technicians ability to change setup parameters Accumet Benchtop Meters 2 11 Accumet Portable Meters 12 13 pH Theory and Measurements 14 15 Conductivity Theory and Measurements 16 Metallic Electrodes ORP Theory and Measurements 16 ISE Theory and Measurements 16 18 Accumet Electrode Specifications 19 23 Buffers Solutions Accessories 24 AR10 Choose the meter that makes your job easiest Two series of Accumet Benchtop Meters are available to match any laboratory s needs Accumet Research AR Benchtop Meters e Five single and multi function models e Unparalleled selection of user options lets you customize the meter to your application Extra large scratch resistant LCD touch screens all models except AR10 respond to a light tap even with gloves or a pencil Two procedural levels to fit your needs Configurable display shows only data you need Plain language prompts and context specific HELP screens guide you through Data acquisition via bidirectional communication with computer or printer Multiple language option English German French or
15. specifications on p 21 19 20 Select the Right pH Electrode for Your Application Application Sample Type Accu pHast Highest Speed and Accuracy Accumet Ag AgCl Standard Line Accumet Calomel Tris Compatible AccuFet Nonglass pH Accumet Gel Filled Line Please NOTE the numbers listed below are partial catalog numbers 13 620 X General Purpose Most Sample Types 2767 26 le 298 279 185 184 2095 70 PYRE PII 20S 284 A6 3 A6 22997 AS 108 104 299 283 294 A6 2564 46 Biological Pharmaceutical Me A 296 2813 116 LOCO A eo dore zoo PYRE PI c atero prs 28 4 52 3 52 20677 2715 20 ou 270 2993 RS ga Proteins Iris Enzymes Education Student Use Emulsions 298 2797 113 9 1 1 49 185 184 169 1835 182 221 220 287 97 98 1 109 300 2893 272 108 104 SA e C 284 62 3 62 abb O 284 61 3 61 Food Cosmetics Oils Flat Surface Food Cheese Agar 22097 7 209 Harsh Environments e Field or Plant Use e Rugged Use 298 279A 13ve 1 149 T6 1178 185 184 OU UE 2990 2057 AD 5001 AP NO 09 219911572 zio deca lgo A 220 531 AP5 19 300 288 272 108 104 SRM CS dois 0A 299 2837 AP OZ AP2 187 258 186 258 Large Sample Size Tall Flasks or Bottles 298 279 296 N
16. the reduction potential of the reference electrode ORP Measurement Systems Oxidation Reduction Potential ORP measurements are displayed in mV using a metallic indicating elec trode and standard reference electrode In principle ORP measurements should not require standardization in practice it may be necessary to check the system against standards of known potential as described in ASTM Method D 1498 The ORP Meter The meter is usually a pH meter operating in mV mode and is chosen based on the required resolution 5mV 1mV or 0 1mV Since automatic temperature compensation does not in most pH meters operate in mV mode and since ORP meas urements do vary with temperature the meter should be adjusted to read OmV with inputs shorted for read out in absolute mV For relative mV readout the meter Is set to some arbitrary value with inputs shorted or with electrodes immersed in a standard solution The Electrode System This consists of two half cells a metallic indicating electrode usually of platinum gold silver or mercury to measure the potential of the reaction and a reference electrode to provide a constant potential and complete the electrical circuit The reference as with pH measurements should be chosen for the compatibility of its junction type and electrolyte with the sample See p 15 for a discussion of reference electrode selection See p 22 for Accumet metallic electrodes ISE Theory and
17. tions containing the ion to be measured The reference electrode is selected based on sample compatibility some ISEs are available as combination electrodes with the indicating half cell and reference half cell joined coaxially in a single body See p 15 for a discussion of reference electrode selection See pp 19 and 23 for Accumet ISEs 17 Testing and Standardization of pH Meters and Electrodes Testing the pH meter e For most current meters attach the BNC shorting cap to the meters BNC input For older meters see your instruction manual ing is outside of this range the meter may need to be electronically calibrated Testing the electrodes e Place the meter in mV mode and measure m in pH 4 and 7 buffers Determine the net change in millivolts Example if the pH 7 buffer reading was 10 0mV and the pH 4 buffer reading was 159 1mV the net change would be 169 1mV Place the meter in mV mode Meter s display should now read 0 0mV 0 2mV If the read e Divide the result net change by 177 5 then multiply by 100 to determine the 96 of the electrodes slope Example 169 1 177 5 x 100 95 3 e New electrodes tresh out of the box have a slope between 95 096 and 10296 If the Slope drops below 92 clean the electrode e f the slope remains below 90 0 or above 102 after cleaning replace the electrode V Standardization of electrodes e Standardization should be performed at l
18. 1 Conductivity Measurement Conductivity Cells such as the Accumet models on p 24 consist of a glass or epoxy body in which plat inum or platinized sensing elements are fixed These sensors contact the solution whose conductivity value is sought Cell constants each cell s unique geomet ric configuration are determined by measuring the conductivity of a standard of known conductive value typically an aqueous solution of KCI To produce a resistance signal appropriate for a given conductivity meter it s important to choose a cell with a compatible cell constant The following table shows optimum conductivity ranges for cells of three different constants Cell Constant Optimum Conductivity Range uS cm 0 1 0 5 to 200 1 0 10 to 2000 10 0 1000 to 200 000 Before use cells should be conditioned in distilled water for at least 10 minutes then standardized to determine the cell constant following instructions Supplied with the meter Conductivity changes consid erably with changes in temperature but the changes are fairly linear and modern meters provide compen sation for accurate standardization See p 24 for Accumet conductivity cells Metallic Electrodes ORP Theory Oxidation reduction measurements are used to deter mine the oxidizing or reducing properties of solutions to monitor chemical reactions in quantitative determi nations of ions and to detect endpoints in titrations In chemical oxidation reduction r
19. 2A Meter onlyt 0 to 999 1 0 0 1 Catalog No 13 636 AP62 13 636 AP62A Specifications and Ordering Information Accumet Portable AP63 pH mV lon C Meter same specifications as Model AP62 plus lon mode Range Relative accuracy Calibration points Resolution Description 1 x 10 to 9 99 x 10 0 17N 5 2 or 3 significant digits Catalog No AP63 Meter Kitt AP63A Meter onlyt 13 636 AP63 13 636 AP63A TIP67 Standard Meter can be submerged for 30 minutes to a depth of 1m and still remain operational Meter only versions include meter 9V battery and user manual Meter Kits include meter 9V battery Accumet liquid filled polymer body pH ATC Ag AgCl electrode user manual and hard carrying case with 4 empty buffer bottles and 4 single use pH buffer pouches 13 Electrochemistry Theory and Measurements pH Theory and Measurement pH Working Theory Since its 1909 introduction pH measurement has become increasingly important in labora tories and industries Close pH control is of primary importance in life processes in sani tary engineering and electroplating and in tex tile pharmaceutical and food industries Modern meters and new electrodes have made pH measurement as simple and convenient as temperature measurement In general pH is a measure of the degree of acidity or alkalinity of a substance It s related to the effective or active acid concentration of a solution by t
20. 5 standards and five point calibration in ion mode Plain language on screen prompts and error messages make getting good results easy even for inexperienced operators Rugged and waterproof A tough ABS plastic housing lets Accumet Portable pH meters take hard use in stride In fact to help you handle even the most difficult remote measurement applications they re waterproof to IP67 standards and will even float if dropped in water Accumet Portable pH meters operate from a 9V battery or with an optional AC adapter Backed by a full two year warranty Not only are Accumet Portable meters accurate versa tile and easy to use they re backed by a full two year warranty Should any Accumet meter fail to perform to specification under normal use during the first two years it will be repaired or replaced at no charge 13 636 100 pH ATC electrode Ag AgCl single junction polypropylene refillable pH ATC electrode calomel single junction polypropylene refillable pH ATC electrode double junction epoxy body gelled Ag AgCl electrolyte ATC probe stainless steel for all AP60 Series meters Accumet Portable Lab Carrying Case 13 620 AP50 13 620 AP51 13 620 AP52 13 620 AP53 13 636 AP69 Note Accumet AP Series Portable Meters are only waterproof to IP67 standards when used with AP Series electrodes above and with AC adapter cap in place Meters are not waterproof when used with AC adapter pHree Trial Offer makes it
21. Buffer Pac 500mL ea of 3x500mL SB105 ISA 5M NaNO 500 13 620 823 color coded pH 4 7 and 10 buffers Calcium 0 1M CaCl 475 13 620 811 400 Red Individual Tear open pH Packets 20 box SB4 100ppm Ca 479 13 620 862 7 00 Yellow Individual Tear open pH Packets 20 box SB7 ET EE a ee 10 00 Blue Individual Tear open pH Packets 20 box SB10 ISA i 500 13 620 805 DE Filling solution 500 13 620 806 DSsor UMOR Sie ZEE Chloride 0 1M Naci 500 13 620 818 Electrode Care and Storage 1000ppm CI 500 13 620 819 Electrode Rinse Solution in Individual 20 box SB15 ISA 5M NaNO 500 13 620 820 Tear open Packets color coded Gray Cyanide ISA 10M NaOH 500 13 620 802 Electrode Storage Solution 1L SE40 1 Fluoride d put m Tonos ses 620 ppm F 620 Electrode Storage Bottle 13 620 499 TISAB 500 13 620 831 Pai ER 4s NaN 375 19620888 Electrode Filling Solutions 1000ppm N 475 13 620 910 Saturated KCI 500mL SP138 500 100ppm N 475 13 620 924 For all calomel single junction electrodes ISA 2M NH S0 475 13 620 850 for outer chamber of all Ag AgC double junction Potassium 0 1M KCI 479 13 620 917 AccuepHast AccuTupH and AccuTupH electrodes m 9M Natl 419 138 620 927 4M KCI Saturated with AgCI 500mL SP135 500 Sodium 10 Natl 900 13 620 826 AS Lo 100ppm as Na 500 13 620 827 For all Ag AgCl singl junction electrodes for inner 1000ppm as Na 500 13 620 828 chamber of all double junction electrodes except ISA 500 13 620 832 Accue pHast and AccuTupH electrodes
22. Fisher Scientific Global Ordering Information f United States China Shanghai Japan Netherlands 1 800 766 7000 phon 86 21 6443 7141 tax 91 3 5484 4736 tax 31 73 6903695 fax Canada Colombia Korea Singapore Pitteburah BA 1 800 234 7437 phone 571 635 3365 tax 82 2 795 3622 3 tax 65 841 1233 tax 412 490 8300 Belgium France Latin America Caribbean United Kingdom 32 56 260 270 tax 33 1 3013 2424 tax 770 871 4726 fax 44 1509 231893 tax Internet address Chile Germany Malaysia Venezuela www fishersci com 562 224 7343 tax 49 2304 932 950 fax 60 3 757 1768 fax 5841 682 472 tax 1999 Fisher Scientific China Beijing Hong Kong Mexico Litho in U S A 8 1202 04 LJ RS 20M SW 3 99 Bulletin No 2823 86 10 6858 7445 tax 852 2602 2782 tax 52 8 343 5828 tax For Other Global Locations please fax inquiries to 603 929 2215 For Technical Application Support within the U S and Canada call 1 800 943 2006 or fax 412 490 6265 For Technical Application Support outside the U S and Canada call 412 490 6260 or fax 412 490 6265
23. Measurement ISE Theory lon Selective Electrodes ISEs respond to a particular ion in solution because of the characteristics of the electrodes sensing membrane Ideally the ISE devel ops an electrical potential which is proportional to the concentration of the ion for which the membrane is selective The most widely used ISE is the glass membrane pH electrode its use is covered on pp 14 15 This section discusses some non pH types of ISEs When an ISE the indicator electrode and a ref erence electrode are placed in a solution and connect ed to a pH ion meter they form a potentiometric cell At equilibrium the meter measures the potential differ ence between the ISE and the reference electrode This potential is proportional to the activity of the ion of interest and the relationship is described by the Nernst Equation _ FO RI E E 23 S log A where E is the measured electrode potential E is the standard potential of the system R is the gas constant T is the temperature in K F is Faraday s constant A is the activity of the ion being measured and n is the number of electrons involved in the reaction Activity A is not the same as concentration The activity of an ion is strongly influenced by the total ionic strength of the solution When ISE measurements are made a determination in concentration units is usu ally desired This is done by adding an lonic Strength Adjuster ISA to samples and standards
24. O 187 53 186 53 284 A6 3 A6 2934 270 111 112 8 290 252 Low lonic Strength PVE 222 OPES gt lO Treated Effluent Nonaqueous Solvents Alcohols Woes Ze 296 261 leo 164 28 4 A6 3 A6 7229 222 286 27i 284 61 3 61 280 LAS 284 57 3 57 Process Monitoring 185 164s B3 182 181 1807 299 283 e ees Pulp amp Paper Semisolids 183 18275 223 222 755 all AR AB Fruit Meat Cheese 2207 280 94 Small Sample Size Test Tubes Small Flasks 2N E2 292 93 PO AUS 296 ds Titration 169 223 222 1835 182 181 180 1109 286 27I 284 61 3 61 Viscous Samples TA 02 Slurries Sludges Waters Acid Rain Boiler Feed 296 281 Distilled Rain Well Drinking Tap e Sea Water e Wastewater 22965 2815 liso 164 296 7 T85 2 2299 28 Esos DUO 222 223 222 284 A6 3 A6 223 222 284 A6 3 A6 229 222 284 61 3 61 280 271 284 61 3 61 286 271 299 283 90s 759 AP20 2290002522 108 104 299 283 108 104 299 2835 AWith U S Standard connector and Pin connector on combinations With BNC connector With BNC and Mini Phone ATC connectors With BNC and Phone ATC connectors Waterproof BNC and Mini Phone ATC connectors With DIN connector With Mini DIN connector Wi
25. Range Temp Range c Length mnm Diameter mm Typical Applications 13 620 46 single Annular Junction 0 14 0 100 108 13 Calcium cyanide Epoxy Body Ag AgCl divalent cation fluoride sodium redox pH 13 620 47 Double Junction Annular 0 14 0 100 108 19 Bromide chloride cop Ceramic Epoxy Body Ag AgCl inner outer cham ber empty for use with sample compatible electrolyte per iodide lead nitrate silver sulfide redox and pH applications requiring compatible electrolyte 2 Cell Models Cat No 4 Cell Models Cat No Glass Body Epoxy Body Glass Body Epoxy Body Accumet Immersion Type Conductivity Cells For Accumet AB30 AR20 and AR50 Meters Cell Constant 0 1cem 13 620 156 13 620 161 Mac 1 0cm 13 620 155 13 620 160 13 620 163 13 620 165 10 0cm 13 620 157 13 620 162 13 620 164 13 620 166 With DIN and Mini ATC connector With Pin connector With Dual Pin connectors pH Color Ingredients Size Catalog No ISE Solution Size mL Catalog No pH Buffers Standards and Solutions for Accumet ISEs 4 00 Red Potassium Biphthalate 500mL SB101 500 Ammonia 0 1M NH CI a SM 7 00 Yellow Potassium Phosphate Monobasic 500mL SB107 500 1000ppm as NH 5 620 ae a ae pH ISA 10M NaOH 500 13 620 802 1000 B Potassi es ee EOOmL SB115 500 Filling solution 500 13 620 803 He pigs UN aeons ees i Bromide 0 1M NaBr 500 13 620 821 Borate amp Potassium Hydroxide 1000ppm Br 500 13 620 822 4 1 10 Fisher
26. Spanish built in Rugged ABS plastic housings resist impacts and chemicals Accumet Basic AB Benchtop Meters e wo models to choose from e Accurate pH mV temperature AB15 and conduc tivity measurement AB30 at an affordable price Extra large LCD shows results clearly Five soft touch membrane switches control all operations On screen plain language prompts and error messages make measurement easier The biggest LCD readouts in their class plus reliable user friendly touchscreen technology No more squinting at tiny displays With the biggest LCD readouts in their class Accumet Benchtop Meters display the information you need precisely and clearly Accumet Basic Benchtop Meters feature a soft touch membrane switch keypad for operation It s tough chemical resistant and simple to use What s more Accumet Research Meters except Model AR10 are the only meters of their type to offer exciting easy to use touchscreen technology proven reliable in measurement value stability indicator buffers or stan thousands of retail applications worldwide TOUCH areas of the screen will withstand millions of touches pHree Trial Offer makes it so easy to try one We re so sure you ll agree that Accumet Meters offer the best performance ver satility and value available that we invite you to try one FREE for 30 days with no risk and no obligation To sched ule your Accumet pHree Trial contact your Fisher Sal
27. TC Polypropylene Calomel Single Junction pH ATC Polypropylene Ag AgCl Single Junction Glass Body Rugged Bulb pH Half Cell Glass Body Universal Glass pH Half Cell Epoxy Body pH Half Cell Full Range High pH Glass Half Cell Standard Glass Body Dri Pak Standard Glass Body Prefilled Miniature Glass Body Standard Glass Body Low Flowrate Cracked Bead Junction Glass Body High Flowrate Sleeve Junction Glass Body High Flowrate Reverse Sleeve Junction Liquid Filled Epoxy Body Gel Filled Epoxy Body Glass Body Single Junction Glass Body Double Junction Single Annular Junction Epoxy Body Ag AgCl Double Junction Annular Ceramic Epoxy Body Ag AgCl inner outer cham ber empty for use with sample compatible electrolyte Glass Body Side Arm for Remote Filling Platinum Half Cell Glass Body Silver Billet Half Cell Glass Body Dual Platinum Plate Combination Dual Platinum Pin Combination Platinum Ag AgCl Combination pH Range Temp Range c 0 100 0 100 0 100 0 100 0 100 0 100 0 100 5 110 5 110 5 110 5 00 5 80 5 80 5 00 5 00 5 00 5 80 0 80 110 5 110 0 100 0 100 5 110 5 100 5 100 10 80 o TUD 5 100 Length mm 140 140 140 102 102 102 102 102 102 102 105 105 4 102 102 102 102 102 105 102 108 108 105 140 140 114 140 140 D
28. al Display Custom LCD e Shows measurements in conductivi dissolved solids to 4 significant figures Screen size SW x 4 H LU dissolved Measurement display height SaM JU a yf elf oe A e Large display shows measurement and Temp etc display height s u H solids units temperature at all times Keypad controls 5 key soft touch Clear user interface with plain lan e Easy to use operation with user prompts M ke ita b y E Pemp Conductivity mode guage prompts make if a breeze on screen stability indicators and Cell constants 0 1 1 0 10 fo use error messages Ranges The Accumet Basic AB30 Conductivity Meter ona aene s ler lenses Conductivity igs dap AMENS Resistivity 30megohm cm to features a large digital display that shows sta fluctuations with ATC probe 100megohm cm bility indicators as well as user prompts and 2 ni cese T TDS 0 to 1 8 x 105ppm error messages in plain language making it nd i eS ve Ru Accuracy 0 5 exceptionally easy to use The AB30 Meter Sono DIeoSs Temperature mode measures conductivity resistivity and total Small compact size conserves valuable id l ER 105 0 C dissolved solids and all measurements are bench space eee E corrected for temperature fluctuations with the inputs ductivity 4 cell DIN conductivity ATC probe Meter size 1l 1 1 Replacement Parts and Accessories for Accumet AB Series Benchtop Meters nd ER J HERREN pH ATC electrode Ag AgCl single junction polypropylene BNC connect
29. ammable data output Print interval Programmable alarm pH mode Range Resolution Relative accuracy Auto manual buffer recognition Calibration points mV mode Range Resolution Accuracy Temperature mode Range Resolution Accuracy Inputs outputs Meter size Meter weight Description 640 x 480 LCD 4 W x 6 H JA H IH 250 data points ves Output on stable time manual 1 to 9 999 sec Yes 2 000 to 20 000 0 1 0 01 0 001 30 002 Yes 5 1800 0 0 1 0 1 5 0 to 105 0 C One 0 2 C BNC Pin ATC bidirec tional RS 232 DIN for FET 6 W x 9 AL x 3 5 H 165 x 235 x 89mm 2 34 Ib 1 1kg Catalog No AR15 Meter Kit 13 636 AR15 includes meter Ag AgCI combination pH electrode ATC probe electrode support arm and bracket user manual and power supply AR15B Meter Kit 13 636 AR15B includes meter AcculupH rugged bulb double junction combination pH electrode for Tris buffer applications ATC probe electrode support arm and bracket user manual and power supply AR15A Meter only 13 636 AR15A includes meter electrode support arm and bracket user manual and power supply The Accumet Research Model AR 10 pH mV C Meter WV e Simple design and operation plus research grade performance e Sleek modern design e Compact small footprint saves valuable bench space The Accumet AR10 Meter gives you reliable research grade pH and mV
30. blocking the reference junction e Soak the electrode tip in 60 C distilled water for 5 to 10 minutes e Check electrode for flow by first blotting the reference junction dry with a wiper e g Kimwipe Pressurize the electrode for 10 seconds then blot the reference junction again If wiper picks up liquid electrode is flowing Liquid Filled Ag AgCl Single Junction Electrodes Start up e Remove the end cot and open the fill hole Add filling solution if necessary e Soak at least 2 hours and preferably overnight in pH 4 buffer solution Storage for less than 1 week e Soak the electrode in SE40 1 electrode storage solution pH 4 or pH 7 buffer solution with fill hole OPEN e Never store electrodes in water after rinsing blot them dry never wipe Storage for longer than 1 week e Saturate the cotton in the end cot with pH 4 buffer and replace the cot on the glass bulb of the elec trode Close the fill hole and pack the electrode in the original box Unblocking the reference junction e Soak the electrode tip in 60 C saturated potassium chloride for 5 to 10 minutes e Check electrode for flow by first blotting the reference junction dry with a wiper e g Kimwipe Pressurize the electrode for 10 seconds then blot the reference junction again If wiper picks up liquid electrode is flowing Gel Filled Ag AgCl Single or Double Junction Electrodes Start up e Remove the end cot from the electr
31. count the chemical relation ship between the standard species and the ion of inter est in the sample The proper choice may be referred to as stoichiometric equivalency units Titrations lon selective electrodes can also be used to detect the endpoint of a titration The ISE can be selected to monitor either the addition of titrant or the depletion of analate The electrode potential is plotted vs the volume of titrant added The volume correspon ding to the equivalence point is determined from the graph and used to calculate sample concentration A number of metallic electrodes are also used in titrations Dual Platinum Wire and Plate Electrodes are used with pH meters and titration instruments in dead stop and amperometric titrations and Silver Billet Electrodes are the choice for silver and halide titrations Accumet metallic electrode specifications are found on p 22 ISE Measurement Systems Potentiometric systems for the measurement of a specific ion include an ion meter calibration standards and an electrode system consisting of an indicating half cell and a reference half cell The lon Meter In general the meter should have a res olution of at least 1mV a meter with 0 1mV resolution or better is preferred For direct read measurements a meter with concentration mode is necessary newer micro processor based models provide resolution to as many as three significant digits with excellent accuracy and repr
32. ctrodes quickly with Inputs the AB15B BioBasic Meter Kit complete with no need to restandardize HIT ATC DIN calomel electrode with built in ATC probe e Small compact size conserves valuable eres For laboratories needing a basic accurate bench space BY OW x TfL x 3 44 H easy to use pH mV meter the AB15 Meter is 140 x 191 x 85mm the perfect choice Meter weight 1 86 Ib 0 8kg Description AB15 Meter Kit Catalog No 13 636 AB15 includes meter Ag AgC combination pH ATC electrode electrode support arm and bracket user manual and power supply AB15B BioBasic Meter Kit 13 636 AB15B includes meter calomel combination pH ATC electrode for Tris buffer applications electrode support arm and bracket user manual and power supply AB15A Meter only 13 636 AB15A includes meter electrode support arm and bracket user Stability indicator manual and power supply Buffer standardization pH mode Easy to read liquid crystal display is the largest in its class The AB 1 5 Meters large liquid crystal display LCD makes it exceptionally easy to use and read Operation is controlled by only five soft touch membrane keys Plain language prompts Temperature indicator m lt AP61 AP62 Accumet Portable AP pH meters are so compact and easy to use you can test for pH mV lon and C just about anywhere Their microprocessor based accuracy and precision coupled with their r
33. digit LCD screen size ZNO etal Measurement display height aH Keypad controls 4 knob rotary Programmable data output Recorder 1800mV pH mode Range 1 99 to 19 99 Resolution 0 01 Relative accuracy 0 02 Manual buffer recognition Yes Calibration points 2 mV mode Range 1800 0 Resolution 1 Accuracy Temperature mode Range Oh Ou oem WOUE Resolution O1 Accuracy 0 5 C Inputs outputs BNC Pin ATC Recorder DIN for FET Meter size 6 W x 9 J4L x 3 7 H 165 x 235 x 89mm Meter weight 2 34 Ib 1kg Description AR10 Meter Kit Catalog No 13 636 AR10 includes meter Ag AgCl combination pH electrode ATC probe electrode support arm and bracket user manual and power supply AR10A Meter only 13 636 AR10A includes meter electrode support arm and bracket user 2 Cell Conductivity Cell Glass Body Epoxy Body Accumet Immersion Type Conductivity Electrodes Cell constant 0 1cm 13 620 156 13 620 161 Cell constant 1 0cm 13 620 155 13 620 160 Cell constant 10 0cm 13 620 157 13 620 162 4 Cell Conductivity Cell Glass Body Epoxy Body 13 620 163 13 620 165 13 620 164 13 620 166 manual and power supply The Accumet Basic Model AB3O Conductivity C Meter 4 An accurate affordable easy to operate m dedicated conductivity meter Easy to read custom LCD displays Features Specifications and Ordering Information information clearly e Reads conductivity resistivity and tot
34. eactions electrons are transferred from one species the reducing agent to another the oxidizing agent Substances vary tremendously in their tendency to act as either oxidizing or reducing agents Tables of stan dard oxidation reduction potentials in the literature are determined relative to the Standard Hydrogen Electrode SHE which has a potential of 0 00V at all temperatures with hydrogen ion activity at 1 00 and the partial pressure of hydrogen gas at 1 00 atmos phere The standard potential E of any oxidation reduction refers to the potential developed vs the SHE when all species are at an activity of 1 00 unit activity A general equation for a reduction reaction IS Ox ne Red where n is the number of electrons Ox is the activity of the oxidized form and Red is the activity of the reduced form The ORP can be expressed by the following form of the Nernst Equation Sco RI Ox E E23 og ar where Ey is the potential developed between the metal lic electrode and the SHE E is the standard reduction potential R is the gas constant T is the temperature in K n is the number of electrons involved in the reac tion F is Faraday s constant Ox is the activity of the oxidized form and Red the activity of the reduced form Since the SHE is rarely used in practice the measured potential Emeas will not be equal to Ey and Emeas must be converted to Ey using the equation Eus Engst Eri where Eres is
35. east once a day and preferably every 2 hours e The filling hole should remain open unless the electrode will be placed in long term storage e At least 2 buffers should be used one below the expected pH of the sample and one above the sample pH to provide linear response in the area of interest Use fresh buffers stir then immerse electrode and an ATC probe into first buffer Standardize according to the meters instructions Rinse the electrode and place it into second buffer Once the meter has accepted the second buffer it will calculate the electrode s slope New electrodes fresh out of the box have a Slope between 95 0 and 102 If the slope drops below 9296 clean the electrode Basic pH Electrode Care and Troubleshooting Tips Liquid Filled Calomel Electrodes and Ag AgCl Double Junction Electrodes Start up e Remove the end cot and open the fill hole Add filling solution if necessary e Soak at least 2 hours and preferably overnight in pH 4 buffer solution Storage for less than 1 week e Soak the electrode in SE40 1 electrode Storage solution pH 4 or pH 7 buffer solution with fill hole OPEN e Never store electrodes in water after rinsing blot them dry never wipe Storage for longer than 1 week e Saturate the cotton in the end cot with pH A buffer and replace the cot on the glass bulb of the electrode Close the fill hole and pack the electrode in the original box Un
36. easurement display height CH e Accepts standard glass or e Large display shows pH or mV and tem Temp etc display height s H AccuFet electrode directly with no perature at all times Keypad controls 5 key soft touch adapter needed membrane r e Autocalibrates with up to 5 pH buffers Internal diagnostics Easy operation accuracy and affordability set from any 3 standard sets and 15 ves the Accumet Basic AB15 Meter apart from difera boko mre the competition o E T Range 1 99 to 19 99 asy to use operation with user prompts Bee alan 0 1 0 01 A large custom LCD makes the AB15 Meter stability indicators and error messages Relative accuracy 0 01 easy to read while plain language prompts and On creen Automatic buffer recognition error messages guide the user through meas A mee TRE Calibration points 5 urements A rugged chemical resistant five xm a un DM mu button soft touch membrane keypad controls all Aser desiree Gira Range 1800 0 operations The AB15 Meter automatically cor adapter needed Resolution 1 rects for temperature fluctuations using an s Automatically corrects for temperature Accuracy 10 2 ATC probe fluctuations with ATC probe Temperature mode E T Range 5 0 C to 105 0 C The AB15 Meter Kit includes Ag AgC com e Standardization curves for standard glass RENT EE 04 C bination pH ATC electrode Life science and and the AccuFet electrode stored in Accuracy 0 2 C other researchers using Tris buffers can choose memory switch ele
37. es See pp 19 and 22 for AccuFet model Selecting a pH Indicating Electrode Fisher offers glass pH indicating electrodes with mem branes of two types of glass Both types are usable over the 0 to 14pH range and feature low error in samples with high sodium content See pp 19 and 22 for specifications and ordering information FS 5 Universal Glass Membranes have low electrical resistance less than 100 megohms at 25 C They re recommended for all routine pH and titration measurements as well as measurements at low temperatures Their sodium error is less than 0 01pH in 0 1N NaOH at 25 C New models with an extra thick membrane are available their rugged bulbs are 40mil in thickness compared to the standard thickness of 8mil making them up to five times more durable under rough handling Full Range High pH Glass Membranes have somewhat higher electrical resistance plus excellent chemical durability They re ideal for frequent or long term measurements in solutions of very high or very low pH value and feature sodium ion error of less than 0 03pH in 0 1N NaOH at 25 C As an alternative to the glass bulb Fisher offers AccuFet combination electrodes with built in ATC probe and ion selective field effect transistor sensor The solid state sensor precludes breakage since theres no glass bulb and the body is of durable epoxy See p 22 for ordering information Reference Electrodes Flectrolyte Filling ca Solu
38. es Representative Just touch the scratch resistant screen with your finger tip to display the information you need including current dards in use with time date stamp plain language prompts date time temperature and much more channel 1 JAK STABLE Stability indi Current measurement value 13 e E NS in use Wilh time Last sid Cer 8 TOs and date amp tamp AJ J E Taah MAOS Ora h samek Plain langbage prompts Touch sid ro Aodordze Date and lime Da ACC AT zuta Eu Her ON 1 auto rege QONiImv F Fisher Scientific m n o L ne c t The Accumet Research Model AR5O pH mV lon Conductivity Meter Powerful and versatile make two different measurements simultaneously Automatically corrects for tempera ture fluctuations with separate ATC probe in each channel Exceptionally easy to use Data acquisition via bidirectional communication with computer Extra large scratch and chemical or printer resistant LCD readout with dual display Multiple language option English Reliable touchscreen technology German French or Spanish built in responds to a light tap of your finger Select from two procedural levels to match your requirements Uses standard glass or AccuFet electrodes with no adapters required Accepts 2 cell and 4 cell conductivity probes Built in replatinizing circuit Now it s easy t
39. full list of setup parameters Advanced Level allows user configurable output and access to all setup parameters Using this feature sci entists can configure the meter in Advanced Level and have a technician perform measurements in Basic Level limiting the technician s ability to change Setup parameters Displays Screen size Measurement display height Temp etc display height Memory Internal diagnostics Programmable data output Print interval Programmable alarm pH mode Range Resolution Relative accuracy Auto manual buffer recognition Calibration points mV mode Range Resolution Accuracy lon mode Range Resolution Relative accuracy Calibration points Incremental methods Conductivity mode Cell constants Ranges Conductivity Resistivity Salinity Accuracy Temperature mode Range Resolution Accuracy Inputs outputs Meter size Meter weight 640 x 480 LCD AN x 6 H JH JH 250 data points Yes Output on stable time manual 1 to 9 999 sec Yes 2 000 to 20 000 0 1 0 01 0 001 0 002 Yes 9 1800 0 0 1 0 1 1x 10 16 999 102 4 significant figures 0 17N 5 KA KS AA AS 0 1 1 0 10 0 to 3 x 10 uS em 30megohm cm to 100megohm cm 2 to 42ppt 40 596 5 0 to 105 C 0 1 C 0 2 C 2 BNC 2 Pin 2 ATC 2 pin conductivity bidirectional RS 232 2 DIN for FET and 4 cell conductivity 6 W x 9 4L x 3 7 H 165 x 235 x 89mm 2 34 Ib 1 1kg Description
40. his equation pH logaH with aH representing the activity of the hydrogen ions in the solution Neglecting activity effects the equation above reduces to pH log H with H representing the concentration of hydrogen ions in solution pH is sometimes referred to as the power of the hydrogen ion in solution The pH of the strong acid 0 01 molar HCI is equal to 2 since its hydrogen ion concentration is 10 molar pH log 107 pH eg The pH scale in water is usually considered to range from 0 to 14 or from an active acid concentration of 1 x 10 to 1 x 10 1 0M to 0 00000000000001M Some current pH meters can measure to 2pH 10 M and to 20pH 109 M The pH scale is based on the dissociation constant of water In pure water a very small number of molecules react with one another to form hydronium ions H30 which account for acidic properties and hydroxide ions OH which account for the basic proper ties of an aqueous solution 2H20 e H30 OH or for simplicity H20 e H 0H At 25 C pure water dissociates until the acid H and base OH concentrations are equal at 1 x 10 molar The product of both concen trations is the dissociation constant Kw Kw H OH Ky 1x 107 1x 107 Ky 1x10 Because its hydrogen ion concentration H equals 1 x 10 molar the pH of pure water at 25 C Is 7 This is referred to as the neu trality point In aqueous solutions at 25 C
41. iameter mm Typical Applications Where glass is a concern for all AR AB Meters Where glass is a concern Where glass is a concern Field Use AP Series Field Use AP Series Field Use AP Series General Purpose Rugged Use General Purpose Plant Use General Purpose Field Plant Use General Purpose Field Plant Use General Purpose Tris General Purpose Tris Small Samples Nonaqueous Viscous Samples Slurries Sludges Viscous Samples Slurries Sludges Field Plant Use Field Plant Use General Purpose General Purpose Tris Calcium cyanide dival ent cation fluoride sodium redox pH Bromide chloride cop per iodide lead nitrate silver sulfide redox and pH applications requiring compatible electrolyte General Purpose ORP measurements redox titrations Silver and halide titrations Chlorine titrations with CI Titrimeter KF dead stop titra tions sulfur analyses Environmental ORP measurements With U S Standard connector and Pin connector on combinations With BNC connector Waterproof BNC and Mini Phone ATC connectors With DIN connector With Mini DIN connector With Pin connector With Dual Pin connectors With Twist Lock waterproof connector 22 ue Catalog No 13 620 537 13 620 536 13 620 535 13 620 534 13 620 533 13 620 532 Description Accumet Polymer Membrane lon Selective Electrodes Calcium Combination Epo
42. int setup allows you to print exactly what you want exactly when you want not just a screen dump Time can be displayed in 12 or 24 hour formats and date in U S or international format Accepts standard BNC glass electrodes as well as an AccuFet electrode directly no need for an adapter Accepts two cell and four cell conductivity probes Builtin replatinizing circuit Automatically corrects for temperature fluctuations with separate ATC Automatic Temperature Compensation probe in each channel Simple customization lets you fit the system to your needs You can easily customize the AR50 Meter screen to set measurement mode operating parameters display only the information you need or match your operating needs There are two ways to do this e Choosing the SYSTEM SETUP OPTIONS menu lets you customize and simplify the screen displays to show exactly the parameters that suit your needs You can edit the date screen configuration time beeper status and print configuration e Customizing within each of the AR50 s operating modes pH mV ion conductivity lets you select Specifications and Ordering Information and set the operating parameters you wish to dis play including resolution buffer sets and similar Settings different for each operating mode to match your requirements You can also choose either of two procedural levels Basic Level displays a reduced set of information and limits user access to the
43. ith all the power and ease of use of the top of the line AR50 It automatically recog nizes USA Euro NIST or custom buffers Its 2 remarkable user interface makes it exception ally easy to use and a full complement of plain language prompts and HELP screens 6 guide you through the measurement process Features Innovative reliable touchscreen technolo gy makes it versatile and easy to use User prompts and context specific HELP screens easily guide user through operation Extensive setup screen allows you to cus tomize the meter to your needs Autocalibrates up to 5 pH buffers from any of 3 standard sets and 15 differ ent buffers also accepts custom buffers and manual calibration Reads pH to 0 001 and mV to O 1 Extensive GLP capabilities with customiz able printer or computer output and 250 reading datalog capability Print setup allows you to print exactly what you want when you want it not just a screen dump Time can be displayed in 12 or 24 hour format date can be displayed in U S or international format Accepts standard glass electrode or AccuFet electrode directly no need for an adapter Automatically corrects for temperature fluctuations with ATC probe An easy to use dedicated pH mV meter for research grade measurements Specifications and Ordering Information Displays Screen size Measurement display height Temp etc display height Memory Internal diagnostics Progr
44. lly formulated sodium Accumet Metallic Electrodes responsive glass bulb for direct measurement of active sodium ion concentration See specifications on p 23 Accumet Gas Sensing Combination ISEs Ammonia and Carbon Dioxide models feature simple two piece construction tough durable body that s highly resistant to chemicals permanently bonded membrane cap unit See specifications on p 23 Solid state pH temperature electrodes the per fect choice for situations where breakable glass B electrodes are hazardous See specifications on p 22 Accumet ISE pH Reference Electrodes Accu pHast Variable We offer five models for ORP silver halide Karl Temperature Electrodes Fischer and chlorine measurements pid See specifications on p 22 Theoretical Single Junction and Double Junction types are excel lent for ISE determinations provide premium perform ance in pH and titration applications too See specifications on p 23 425 Cool Down Accumet ISE Electrodes Accumet Polymer Membrane Combination ISEs 0 10 20 30 40 50 60 70 80 90 100 T C Fast accurate pH measurements Glass and epoxy bodies patented reference design Deliver Calcium Nitrate and Potassium Combinations feature superlative performance even in samples with rugged epoxy bodies and refillable reference section widely varying temperatures See specifications on p 23 See
45. lver Sulfide half cells have epoxy ples Easy clean junction plastic body choice Wide choice glass or plastic calomel or Ag AgCl low bodies sensing membrane with low microporosity and of AccuopHast and Ag AgCl reference types maintenance single or double junction liquid or gel mirror like finish to minimize sample retention plus models with ATC element built in for small filled flat surface and microsize electrodes Bromide Chloride Copper Fluoride Lead and samples See specifications on p 21 See specifications on pp 21 25 Silver Sulfide Combinations have glass bodies excel AccuTupH Rugged Bulb pH Electrodes All Accumet refillable electrodes feature our lent range and precision See specifications on p 23 patented easy to use fill hole technology amil Standard Accumet Electrode 40mil AccuTupH amp Rugged Bulb Best choice for durability Made to be up to 40 times tougher than conventional glass pH elec Accumet Conductivity Cells trodes without sacrificing response time Available in pH half cell variable temperature combination and standard combination models Accumet Glass Membrane ISEs See specifications on p 21 Two cell models 0 1 1 0 and 10 0cm cell constants E E T A eene t i bo 4 cell models with cell constants of 1 0 and cm Glass or epoxy bodies See specifications on p 23 B sodium Glass Body Half Cell and Sodium Glass Body Combination have specia
46. measuring capabil ities in a package that is ideal for classrooms and industrial labs A big four digit LCD makes reading measurements easy and four knob rotary control makes it simple to use Features e Reads pH to 0 01 and mV to 1 e Solid state circuitry with digital display and rotary knobs e deal for educational use e Automatically corrects for temperature fluctuations with ATC probe Replacement Parts and Accessories for Accumet AR Series Benchtop Meters Description For Accumet AR Series Benchtop Meters pH combination electrode Ag AgCl single junction glass body BNC connector replacement for AR10 AR15 AR20 AR25 AR50 AccuFet solid state pH ATC combination electrode Ag AgC ATC probe stainless steel for all AR Series meters Electrode support arm for all AR Series meters Electrode arm bracket for all AR Series meters Power Supply 1 15V 60Hz US plug Catalog No 13 620 285 13 620 755 13 620 19 13 637 671 13 637 671A 13 636 100 For Accumet AR50 AR25 AR20 AR15 Benchtop Meters Printer including printer cable ribbon paper For 115V Printer Paper Printer Replacement Ribbon Printer Cable Computer Cable for AR Series 9 pin to 9 pin Conductivity Cells for AB30 AR20 AR50 13 637 670 13 637 669 13 637 668 13 637 667 13 637 680 an easy to use digital pH meter Performance reliability and economy in Specifications and Ordering Information Displays 4
47. n be displayed in U S or international format e Accepts standard glass electrodes or an AccuFef electrode directly no need for an adapter e Automatically corrects for temperature fluc tuations with ATC probe view two parameters at once Dual channels let you measure and Specifications and Ordering Information 640 x 480 LCD 4 W x 6 H ain YT Extensive Displays Screen size Measurement display height Temp etc display height Menu options Memory Internal diagnostics Programmable data output Print interval Programmable alarm pH mode Range Resolution Relative accuracy Auto manual buffer recognition Calibration points mV mode Range Resolution Accuracy lon mode Range Resolution Relative accuracy Calibration points Incremental methods Temperature mode Range Resolution Accuracy Inputs outputs Meter size Meter weight 250 data points Yes Output on stable time manual 1 to 9 999 sec Yes 2 000 to 20 000 0 1 0 01 0 001 30 002 Yes 5 1800 0 0 1 0 1 1 x 10 to 9 99 x 10 4 significant figures 0 17N 2 KA KS AA AS 5 0 to 105 0 C IIO 0 2 C 2 BNG 2 Pin 2 ANG bidirectional RS 232 DIN for FET 6 W x 9 AAL x 3 5 H 165 x 235 x 89mm 2 34 Ib 1 1kg Description AR25 Meter Kit Catalog No 13 636 AR25 includes meter Ag AgCI combination pH electrode ATC probe electrode support arm and bracket user manual and
48. o ducibility And for incremental methods meters now available that will automatically perform the needed calcu lations providing readout in ppm 96 mg mL mg L or most any units you choose Some current meters have the ability to measure via multiple inputs permitting simulta neous testing of different samples or measurement of more than one ion in a single sample ISE Standardization and Adjustment Solutions The ion meter electrode system must be standardized by immersing the electrodes into solutions having a known concentration of the ion of interest ISE standards are available in a variety of molar ppm and percent concen trations Calibration may be done at a single point usual ly on less sophisticated meters or at up to five standardi zation points using newer meters Additionally an ionic strength adjuster is required to eliminate interference from other ions and permit readout in units of concentration rather than activity Since some ISEs have a restricted pH range a pH adjustment solution may also be necessary Other special reagents and solu tions are available for specific applications The lon Selective Electrode System The electrode system consists of an indicating electrode which develops a potential dependent on the ionic activity of the sample and a reference electrode which provides a constant potential and completes the circuit The indicat ing electrode is chosen for its specific response in solu
49. o put a complete electrochemical lab at your fingertips An advanced design and incredible ease of use make the new Accumet AR50 the most versatile reliable meter of its type you can buy today The AR50 offers you the advantages and versatility of having a research grade pH mV ion and conductiv ity meter all in a single instrument providing you with a dedicated system for a wide range of electrochemical analyses Current measurement value Si amp bility indicator Features The largest display available yet com pact design saves valuable benchtop space User prompts and context specific HELP screens easily guide user through operation Extensive setup screens allow you to customize the meter to your needs Autocalibrates with up to 5 pH buffers from any of 3 standard sets and 15 different buffers also accepts custom buffers and manual calibration Innovative touchscreen makes it versatile and easy to use Dual channel meter allows you to meas ure two parameters at once and view results from both channels on screen simultaneously Reads pH to 0 001 mV to 0 1 plus conductivity resistivity salinity and TDS Reads ISE in ppm mg ml and mole L Direct and indirect ISE measurements including known addition and subtrac tion and analate addition and subtraction methods Extensive CLP capabilities with customiz able printer or computer output and 250 reading datalog capability Pr
50. ode s tip e Soak at least 2 hours and preferably overnight in pH 4 buffer solution Storage for less than 1 week e Soak the electrode in SE40 1 electrode storage solution pH 4 or pH 7 buffer solution Storage for longer than 1 week e Saturate the cotton in the end cot with pH 4 buffer and replace the cot on the glass bulb of the elec trode Pack the electrode in the original box and store in upright position e Never store electrodes in water after rinsing blot them dry never wipe Unblocking the reference junction e Soak the electrode tip in 60 C saturated potassium chloride solution for 5 to 10 minutes Accumet Electrodes for pH Titrations ORP and lon Selective Electrode Analysis Over 30 years of experience in the design development and manufacture of electrodes go into each Accumet electrode from Fisher Scientific e Each electrode is individually tested serialized to meet GLP requirements and backed by Fisher s Technical Applications staff e No matter what the application we offer an ideal electrode for fast accurate pH titration ORP conductivity or ISE measurements Accumet pH Electrodes Accumet pH Reference and Accumet Solid State ISEs AccuFlow Flushable Junction pH ATC Combination Electrodes and pH Electrodes Cyanide Combination has durable epoxy body homo geneous membrane Bromide Chloride Copper Perfect choice for even the most difficult sam Fluoride Lead and Si
51. onized water and in difficult samples such as slurries emulsions and suspensions Sleeve junc tions can be removed or slid out of the way to clean or refresh the junction The reverse sleeve type is designed to prevent loss of the sleeve Some annu lar junction models have spring loaded caps for flow adjustment and easy cleaning Porous ceramic junctions offer moderate flowrates of about 8uL hr providing excellent solu tion contact with minimal need for electrolyte replenishment They re recommended for the majori ty of routine pH and titration measurements Cracked bead junctions allow the least amount of electrolyte flow only 0 5 to 5 0uL hr yet exhibit minimal problems with clogging of the junction Nonflowing junctions are most often found in polymer body electrodes designed for applications where minimal electrode maintenance is desirable The electrolyte is usually a gel contact is by ionic diffusion through a porous junction rather than by liquid flow These types are useful for in plant monitoring field measurement and classroom use Double junction electrodes permit isolation of the reference element and its electrolyte by enclosing them in an inner electrode body The flowrate is deter mined by the second junction contained in the outer body of the electrode A choice of outer junctions and electrolytes permits matching of electrode to sample Internal elements provide a fixed potential of excellent stability
52. or 13 620 530 1 86 Ib 0 8kg replacement for AB15 TEE pH ATC electrode calomel single junction polypropylene BNC connector 13 620 531 replacement for BioBasic AB15B AB30 Meter Kit 13 636 AB30 AccuFet solid state pH ATC combination electrode Ag AgCI 13 620 755 includes meter ATC probe electrode support arm and ATC probe stainless steel for all AB Series meters 13 620 19 bracket user manual and power supply Electrode support arm for all AB Series meters 13 637 671 AB30A Meter only 13 636 AB30A Electrode arm bracket for all AB Series meters 13 637 671A includes meter electrode support arm and bracket user Power Supply 1 15V 60Hz US plug 13 636 100 manual and power supply Conductivity Cells for AB30 2 Cell Conductivity Cell 4 Cell Conductivity Cell Glass Body Epoxy Body Glass Body Epoxy Body Accumet Immersion Type Conductivity Electrodes Cell constant 0 1 m 13 620 156 13 620 161 ue ee Cell constant 1 0cm 13 620 155 13 620 160 13 620 163 13 620 165 Cell constant 10 0cm 13 620 157 13 620 162 13 620 164 13 620 166 The Accumet Basic Model AB 15 pH mV C Meter e Same quality as our top of the line AR50 Research Meter NES N Features Intuitive simple operation and high accuracy in a compact affordable meter Specifications and Ordering Information e Measures pH mV and relative mV to Display Custom LCD Largest LCD readout in its class 0 01 pH and ImV Screen size 3W x 4 H M
53. single Junction 0 14 5 100 106 10 General Purpose 13 620 285 Ag AgCl Reference 13 620 222 Double Junction 0 14 5 100 106 10 General Purpose 13 620 223 Ag AgCl Reference Tris Titration 13 620 271 Single Junction 0 14 5 80 106 10 General Purpose 13 620 286 Calomel Reference Tris Water 13 620 94 Micro tip Miniature Length 0 14 5 110 60 6 small Samples Ag AgCl Reference 13 620 92 Micro tip Standard Length 0 14 5 110 100 6 Small Samples 13 620 291 Ag AgCl Reference Test Tubes 13 620 93 Micro tip Extra Long 0 14 5 110 150 6 Small Samples 13 620 292 Ag AgCl Reference Flasks Tubes 13 620 270 Semimicro Extra Long 0 14 5 80 150 6 Small Samples 13 620 293 Calomel Reference Tris Test Tubes z 13 620 530 pH ATC Polypropylene 0 14 0 100 106 10 Field Plant Use 13 620 AP1 Body Ag AgCl Reference 13 620 531 pH ATC Polypropylene 0 14 5 80 106 10 Field Plant Use Body Calomel Reference Tris 13 620 97 Polypropylene Body 0 14 0 100 106 10 Field Plant Use 13 620 287 Ag AgCl Reference Student Use 13 620 300 Polypropylene Body 0 14 5 80 106 10 Field Plant Use Calomel Reference Tris Student Use 13 620 220 Polypropylene Body 0 14 5 100 106 10 Rugged Use 13 620 221 Double Junction Ag AgCI Tris Student Use 13 620 272 Epoxy Body 0 14 5 00 106 10 Field Plant Use 13 620 288 Calomel Reference Tris Student Use 13 620 83 Epoxy Body Flat Surface 0 14 0 100 114 138 Food Cheese
54. so easy fo try one We re so sure you ll agree that Accumet Portable meters offer the best performance versatility and value available that we invite you to try one FREE for 30 days with no risk and no obligation To schedule your Accumet pHree Trial contact your Fisher Sales Representative Mode Measurement value Stability indicator Temperature Plain language prompts Buffers or standards in use Simple button operation Specifications and Ordering Information Accumet Portable AP61 pH C Meter Displays screen size Measurement characters Other data characters Keypad controls Internal diagnostics Waterproofing pH mode Range Resolution Relative accuracy Auto buffer recognition Calibration points Temperature mode Range Resolution Relative accuracy Compensation Inputs Electrical requirements Battery life Description AP61 Meter Kitt AP61A Meter onlyt Custom LCD 146W x 2 H hg H Mtl 6 key membrane Self test error message IP67 1 99 to 19 99 0 1 0 01 0 01 DNC AN Me ato 5 0 to 100 0 C DERE 0 3 C Automatic BNC ATC 9V battery or optional AC adapter gt 200 hr Catalog No 13 636 AP61 13 636 AP61A Specifications and Ordering Information Accumet Portable AP62 pH mV C Meter same specifications as Model AP61 plus mV mode Range Resolution Relative accuracy Description AP62 Meter Kitt AP6
55. th Pin connector With Dual Pin connectors With Twist Lock waterproof connector Indicating Electrode Reference Electrode Refer to the next 3 pages for detailed information on each electrode NOTE All Accumet Electrodes are catalog number 13 620 X Catalog No Description pH Range Temp Range c Length mm Diameter mm Typical Applications d c Nn ie With Accu epHast Reference 13 620 117 pH ATC 0 14 0 100 175 12 General Purpose Tris 13 620 116 pH 0 14 0 100 1 12 soils sludges viscous With Double Junction Reference 13 620 110 pH ATC 0 100 175 12 General Purpose Tris 13 620 109 pH 0 100 175 12 soils sludges viscous HS 13 620 281 Standard Glass Body 0 14 5 100 102 10 General Purpose 13 620 296 Tris Water 13 620 280 4 MicroProbe Glass 0 14 5 100 165 5 Small Samples 13 620 297 Body Tris 13 620 279 4 Extra Long Epoxy 0 14 0 100 140 10 Field Plant Use 13 620 298 Body Tris 13 620 113 pH ATC Extra Long 0 14 5 100 143 10 Field Plant Use Epoxy Body Tris 13 620 114 pH ATC Extra Long 0 14 5 100 143 10 Field Plant Use Epoxy Body Tris 13 620 184 Double Junction 0 14 5 100 102 10 General Purpose a 13 620 185 Tris Rugged m 13 620 180 4 Single Junction 0 14 0 100 102 10 General Purpose 13 620 181 Ag AgCl Reference Rugged Use 13 620 182 Double Junction 0 14 0 100 102 10 General Purpose 13 620 183 Ag AgCl Reference Tris Water E 13 620 90
56. the product of H and OH must remain constant at 1 x 105 an increase in either acid or base concentration always results in a decrease in the other Hence a solution of the strong base 0 01M NaOH will have a hydrogen ion concentration of _ Kw 10755 anui Lie OH 10 zt Thus pH log 10 pH 12 pH Measurement Systems Although pH can be determined using colorimetric indicators or indicator papers the preferred method is potentiometric measurement using a pH meter and electrode system This method is based on the fact that certain electrodes immersed in a solution produce a voltage that is related to the pH value of the solution in a very precise way This voltage can be predicted by the Nernst equation Simplified the equation is Emeas E La RT pH where Emeas IS the measured voltage E is the total of all constant voltages in the measurement system R is the Gas Law constant T is the temperature in K n is the charge of the ion and F is Faraday s constant The pH Meter The pH Meter is a specialized voltmeter It can accu rately measure small voltage changes at extremely high resistances exhibited by electrodes And it can adjust to the pH and voltage characteristics of the elec trode system Most modern pH meters incorporate manual or automatic temperature compensation to correct for variations in pH value of a given solution with sample temperature as expressed in the Nernst equation To
57. the reciprocal of the solution s electrical resistance Conductance 1 Resistance Conductivity measurements however generally involve determining the resistance of a small portion of solution between two parallel electrodes when an alternating potential is applied Conductivity values are related to the conductance of a solution by the physical dimensions area and length of the measuring cell called the cell constant Conductance Conductivity x Cell Constant Cell Constant Area Length Polarization effects which would impair the accuracy of the measurements are avoided by using AC potential rather than DC and by coating the electrode s surface area with platinum black Conductivity measurements provide an easy way to assess the quality of water or of various aqueous solutions Conductivity measurements are reported as Siemens cm since the value is measured between opposite faces of a cell of known cubic configuration With aqueous solutions values are most frequently measured in uSiemens per cm uS cm or milliSiemens per cm mS cm some users prefer to use resistivity units to describe their water particularly where very pure water is involved Units used to measure resistivity are megohms cm they re simply the reciprocals of the conductivity units The chart below shows the relation ship between these two units Conductivity Resistivity uS cm megohms cm 0 056 18 0 0 1 10 0 1 0 1 0 25 0 4 10 0 0
58. tion Reference Element Porous Junction The basic requirements of the reference half cell are to complete the electrical circuit and to provide a stable reference potential The probe contains a reference element usually calomel or silver silver chloride immersed in an electrolyte solution of fixed ionic concentration This produces a constant voltage despite sample composition The circuit is completed by allowing a small flow of the electrolyte to pass through a junction in the probe tip or by ionic diffusion in an electrode filled with gelled electrolyte Selecting a Reference Electrode To maintain constant junction potential under specific measurement conditions requires an adequate flow of electrolyte So the choice of reference electrode is made based on the electrodes flowrate which depends on its junction type and on the characteristics of its internal element and electrolyte relative to the sample Liquid Junctions cover the majority of applications with flowrates from 0 5 to 100uL hr These junctions perform best with the least junction potential In most cases this occurs with a fast flowing junction but rapid electrolyte flow can cause significant sample con tamination Hence the need for a variety of junctions to provide a selection of flowrates e Sleeve and annular junctions provide flowrates to 100uL Rr for enhanced conductivity and response in solutions of low ionic strength such as dei
59. traction With the Known methods the initial electrode out put is measured in the sample solution then an aliquot of standard is added and the final electrode output is measured The concentration of the sample can then be calculated from the change in the electrodes output Equations for known addition and subtraction follow Known Addition Cs Csi Vstd i V T Veta 1 485 V Known Subtraction Gee Csia Vstd Vs Vs Vs 10475 where C is the concentration of the sample Cs is the concentration of the standard V is the sample volume Vta IS the volume of standard AE is the change in electrode output and S is the electrodes slope In the Analate methods the initial reading is taken with the electrode immersed in the standard then an aliquot of sample is added and the final reading taken sample concentration is then calculated from the change in electrode output Analate Addition Cs Coa R2 10888 Ye S Analate Subtraction Ce Gas 3 Vs i 10e With modern ISE meters operating in Concen tration Known Addition or Analate Addition modes the units of the sample result will be identical to those of the standards used in calibration However when oper ating in either the Known Subtraction or Analate Subtraction modes the ion of interest in the sample is not identical to the standard species So it s necessary to enter the standard values in concentration units which take into detailed ac
60. ues at various temperatures Temp 4 01 Buffer 6 86 Buffer 9 18 Buffer 0 05M Potassium 1 025M KH PO 0 01M Borax Acid Phthalate 0 025M NagHPO 0 C 4 00pH 6 98pH 9 46pH 10 4 00 6 92 9 33 20 4 00 6 88 9 22 2 4 01 6 86 9 18 30 4 02 6 85 9 14 40 4 04 6 04 9 07 90 4 06 6 83 9 01 60 4 09 6 84 8 96 70 4 13 6 85 0 92 90 4 16 6 86 0 00 90 4 21 6 88 0 85 The Electrode System The electrode system consists of two half cells a pH indicating electrode which develops a potential dependent on the pH of a solution and a reference electrode which provides a constant potential and completes the electrical circuit Using separate pH indicating and reference half cells lets you select each cell without compromise tailor the system precisely to the sample s nature and achieve the best accuracy It can mean lower replacement costs too since usually only one of a pair is broken Nevertheless the combination electrode an indicating half cell and a reference half cell joined coax ially is being used more frequently for the conven lence and compactness it offers Those which incorpo rate a temperature probe can provide temperature read out and compensation with ATC capable meters Some types of pH reference and combination electrodes are discussed below and on the following page The Electrode Pair Internal Reference Glass Body Element Glass Membrane Buffered Electrolyte Filling Sol
61. ugged waterproof design make them ideal for a variety of remote testing applications Offering up to five calibration points Accumet Portable pH meters provide the ultimate in portable pH measurement Small enough to fit in your shirt pocket Compact rugged Accumet Portable pH meters can be used almost anywhere from the R amp D lab to the factory floor to the job site Their trim shape and rubberized wraparound grips make them comfortable to hold and operate with just one hand Choose the AP61 for pH only measurements the AP62 for Three models to match your pH mV or the AP63 for pH mV or ion applica remote testing and tions All models also measure temperature in C sampling requirements Large easy to read LCD readouts Same simple intuitive operation as Accumet Basic Series Benchtop Meters Six button soft touch keypad Ergonomic design makes them comfortable to hold Waterproof to IP67 standards in fact they float Power Supply 115V 60Hz US plug Easy to use comfortable to hold A user interface similar to that used in Accumet Basic Benchtop meters makes Accumet Portable pH meters exceptionally easy to operate Six sealed soft touch entry keys let you scroll easily through menu options pH mode features selectable resolution to 0 01 auto matic temperature compensation automatic recogni tion of 5 buffers and five point calibration The AP63 also features automatic recognition of
62. ution pH Indicating Electrodes The traditional pH electrode consists of a glass sens ing membrane of special electrically conductive glass bonded to a nonconductive tube of glass or plas tic called the body and an internal reference element usually Ag AgCl immersed in a buffered electrolyte of fixed pH value and ionic concentration This design assures that constant potentials are devel oped on the inner surface of the glass membrane and on the internal reference element When the electrode is immersed in a solution of pH 7 the sum of these fixed voltages approximately balances the voltage developed on the outer surface of the glass membrane and the separate reference electrode Thus in a pH 7 solution the total potential output of the system is near OmV In solutions of more or less than pH 7 the potential on the outer membrane surface changes in proportion to the sample pH The voltage change is sensed by the meter and displayed as a pH value FET pH Sensor Recent designs have replaced the glass pH mem brane with a sensor comprising the gate connection of an ion sensitive FET Field Effect Transistor A pH related potential is developed across the gate of this semiconductor which in turn controls the current flowing through the transistor The current output is in essence dependent on the activity of the hydronium ion in the solution being measured Most such elec trodes are designed as combination electrod
63. xy Body Nitrate Combination Epoxy Body Potassium Combination Epoxy Body Range M ppm 10 to 10 0 04 to 400 7x 10 to 1 0 5 to 62 000 10 to 1 0 04 to 39 000 Accumet Solid State lon Selective Electrodes 13 620 520 13 620 521 13 620 524 13 620 525 13 620 518 13 620 519 13 620 526 13 620 527 13 620 540 13 620 541 13 620 546 13 620 547 13 620 539 13 620 538 13 620 522 13 620 523 13 620 528 13 620 529 13 620 542 13 620 543 13 620 548 13 620 549 13 620 544 13 620 545 13 620 550 13 620 551 Bromide Half Cell Epoxy Body Bromide Combination Glass Body Chloride Half Cell Epoxy Body Chloride Combination Glass Body Cupric Half Cell Epoxy Body Cupric Combination Glass Body Cyanide Combination Epoxy Body Fluoride Half Cell Epoxy Body Fluoride Combination Glass Body Lead Half Cell Epoxy Body Lead Combination Glass Body Silver Sulfide Half Cell Epoxy Body Silver Sulfide Combi nation Glass Body 5 x 105 to 1 0 4 to 79 000 5 x 105 to 1 0 4 to 79 000 5 x 105 to 1 1 8 to 35 500 5x 10 to 1 1 8 to 35 500 10 to 107 6 4x 10 to 6350 10 to 107 6 4x 10 to 6350 5x 10 to 10 0 1 to 260 Sat to 10 Sat to 0 02 Sat to 10 Sat to 0 02 105 to 10 0 2 to 20 700 10 to 107 0 2 to 20 700 107 to 1 0 Ag S Interferences Mg ZW Ba K Na NI Gu Fes Sr H Hg Pht Cl NOz Br CN ClOs F CIO
64. y In most combinations the pH sensing cell is enclosed in a tube its membrane is exposed at the probe tip The annular space around the inner tube contains the ref erence element electrolyte and junction Advantages of this design are handling convenience and compactness allowing measurements of smaller Samples and in narrow vessels They re practical for field measurements too and come in a wide range of lengths and diameters for use in a variety of containers test tubes centrifuge tubes fraction collectors cuvets and flasks among others Even greater compactness is achieved in models which incorporate an Automatic Temperature Compensation probe ATC within the combination electrode s body See pp 21 and 22 for Accumet combination electrodes including Accu epHast variable temperature and AccuFet solid slate electrodes Electrochemistry Theory and Measurements cont Conductivity Theory and Measurement Conductivity Theory Conductance is a value associated with the ability of primarily aqueous solutions to carry an electrical current Though water itself is a rather poor conductor of electricity the presence of ions in an aqueous solution increases the solution s conductance consid erably The current is carried by migration of ions dissolved in the water The solution s conductance is proportional to the concen tration of ionic species present as well as the ions charge and mobility and is defined as

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