797 VA Computrace The all-round instrument for voltammetry 797 VA Computrace in brief 02 The 797 VA Computrace is a modern voltammetric meas-The new potentiostat with galvanostat built into the in - uring stand that is connected to a PC via a USB port. The strument guarantees outstanding sensitivity with re du ced PC software provided controls the measurement, records noise. The unique Multi-Mode Electrode pro (MME pro) the measuring data and evaluates it. Due to the well-laid-and rotating disk electrodes (RDE) made from various out program structure operation is very easy. All the materials are available as working electrodes. methods described in the Metrohm Application Bulletins and Application Notes are preinstalled. The most important applications Stripping voltammetry CVS EXPLORATORY Voltammetric trace analysis of Cyclic Voltammetric Stripping for The Metrohm concept for electro- metal ions and other substances the determination of additives in chemistry training electroplating baths 03 Highlights The 797 VA Computrace opens up new possibilities: • Voltammetric trace analysis and additive determination in electroplating baths with a single instrument • Outstanding sensitivity thanks to a combination of the unique Multi-Mode Electrode with the newly designed potentiostat • Automation with the 863 Compact Autosampler or 838 Advanced Sample Processor • Data archiving in the database program Autodatabase with report generator • More than 220 important analytical methods are supplied • Output of the result in as many formats as required • Unique EXPLORATORY mode specially designed for training students in technical colleges and universities. Ideal in combination with the Metrohm monographs «Introduction to Polarography and Voltammetry» and «Practical Voltammetry» • Built-in quality assurance with GLP mode, individual rights of access for each user and automatic electrode test • Simple operation thanks to the clearly laid out user interface oriented on Windows operating procedures Application 1 – voltammetric trace analysis 04 Analysis of heavy metals – total concentration ... High ionic concentrations? No problem with VA! For a fraction of the purchase price of an AAS or ICP Samples with high ionic concentrations are no problem instrument it is possible to carry out metal analyses with for voltammetry. This means that voltammetry is predes-the same or improved sensitivity. The only thing required tined for the analysis of: apart from small amounts of reagents is a small amount of pure nitrogen. No expensive flammable gases, no • Water, wastewater and seawater specially constructed fume hoods in the laboratory, no • Salts, pure chemicals costly metal vapor lamps. • Electroplating baths • Foodstuffs ... and speciation Spectroscopic methods can only determine the total concentration of the metals. With voltammetry it is also Detection limits possible to differentiate between various oxidation states Antimony SbIII/SbV 200 ppt of metal ions or between free and bound metal ions. This Arsenic AsIII/AsV 100 ppt allows statements to be made about the biological avail-Bismuth Bi 500 ppt ability and toxicity of heavy metals and makes this tech-Cadmium Cd 50 ppt nique a valuable tool for environmental analysis. In con-Chromium CrIII/CrVI 25 ppt trast, spectroscopy requires complicated separation of Cobalt Co 50 ppt the metal species before comparable statements can be Copper Cu 50 ppt made. Iron FeII/FeIII 50 ppt Lead Pb 50 ppt Mercury Hg 100 ppt Molybdenum Mo 50 ppt Nickel Ni 50 ppt Platinum Pt 0.1 ppt Rhodium Rh 0.1 ppt Selenium SeIV/SeVI 300 ppt Thallium Tl 50 ppt Tungsten W 200 ppt Uranium U 25 ppt Zinc Zn 50 ppt 1 ppt = 1 ng/kg 05 Specific analysis of organic compounds Not only metals, but also many different organic compounds can be determined by voltammetry. VA can be used in organic chemistry, e.g. for the analysis of contami-nants, or in pharmaceutical chemistry for the determination of the active substance concentrations. Ex am ples of interesting applications: • 4-Carboxybenzaldehyde in terephthalic acid • Free styrene in polystyrene • Vitamins in juices, vitamin preparations Determination of anions A range of special anions can also be determined voltam-metrically. Of particular interest is the analysis of the en - vironmentally relevant species cyanide, sulfide or nitrite and nitrate. Application 2 – CVS for the determination of organic additives in electroplating baths 06 Cyclic Voltammetric Stripping Analysis (CVS) and Cyclic The most important fields of application for the Pulse Voltammetric Stripping Analysis (CPVS) are widely method are: used methods in the electroplating industry for the determination of organic additives in electroplating baths. For • Acidic copper baths many technical coatings, particularly in the manufacture • Tin-lead baths and tin baths of PCBs and semiconductor components, this method is • Alkaline zinc baths an essential part of production control. The quantitative determination of the additive is carried out indirectly via Quantification of the various types of additives requires its influence on the deposition of the main component of special calibration techniques: the so-called brighteners the electroplating bath. As the measurement is based on are determined using the Linear Approximation Technique an electrode reaction that corresponds to the production (LAT) or Modified Linear Approximation Technique process, the activity of the additive and thus its effective- (MLAT). The determination of the suppressors is carried ness in the galvanization process can be measured out by Dilution Titration (DT), the determination of level-directly. ers by means of the Response Curve (RC). In these analyses a simple, robust and inexpensive rotating disk electrode made of platinum is used. The electro-chemical conditioning of the electrode, which is necessary before each measurement, is part of the determination method. It is repeated automatically until the measured value remains constant. With CVS or CPVS the concentration of the additive can be determined with superior accuracy. The effective concentration of the particular additive in the bath sample is shown and printed out directly in mL additive per L bath liquid. This means that topping up to the preset bath concentration can be carried out very accurately. This guarantees continuous and interference-free operation of the unit. In particular, the accuracy of the analytical results has helped the method to become generally accepted in the electroplating industry. Other methods, e.g. the classical Hull cell method, do not allow the concentration to be determined, but only provide an assess-ment of the quality of the deposited metal layer. 07 One of the preinstalled methods is loaded to carry out the determination. Once a few parameters have been adapted, the analysis can be started. Additional applications with the corresponding methods are available in the Metrohm Application Bulletins and Application Notes; these can be accessed on our website. The organic additives can be determined either manually or automatically, depending on the necessary sample frequency for monitoring the electroplating process. Solutions can be added automatically by means of model 800 Dosino dosing systems; fully automated systems can be realized with the 838 Advanced VA Sample Processor, which allows large series of samples to be analyzed. Application 3 – 797 VA Computrace as a training tool 08 EXPLORATORY is the program part of the 797 VA Com-face and ease of operation make the instrument the pu trace specially designed for training purposes. It is perfect tool for hands-on training in voltammetry in uni-characterized by its clear layout and intuitive operation. versities, technical colleges, vocational schools and also The experimental parameters and the associated voltam-in production facilities. mograms can be checked at a single glance. User inter-In the EXPLORATORY mode the following current measuring techniques are available: Sampled DC Direct current DP Differential pulse SQW Square wave (according to Osteryoung) AC Alternating current (1st and 2nd harmonic, phase-selective) CV Cyclic voltammetry NP Normal pulse PSA Potentiometric stripping analysis (stripping chronopotentiometry with chemical oxidation) CCPSA Constant current potentiometric stripping analysis (stripping chronopotentiometry with oxidation/ reduction by constant current) CVS Cyclic voltammetric stripping (cyclic voltammetry for determination of additives in electroplating baths) CPVS Cyclic pulse voltammetric stripping (pulse chronoamperometry for determination of additives in electroplating baths) EXPLORATORY is curve-oriented. Voltammograms and EXPLORATORY can also evaluate the measured curves: as their associated parameters are shown in 2 adjacent win-in DETERMINATION the peak or wave evaluation can be dows. At the end of the measurement the conditions can carried out automatically or manually after displacing the be varied and the altered signal recorded. The different foot points. voltammograms can be superimposed for direct com-parison. 09 These features make the EXPLORATORY part of the pro-13 experiments in their consecutive order, as they prefer. gram highly useful in developing and optimizing meth-Detailed description of the problem to be solved and ods for the quantitative determination of substances. The references to the literature are followed by examples of optimized voltammetric parameters can be accepted curves and solutions. Thus, the basic theoretical know-directly in the determination method in the program part how is provided in a compact manner. Even technicians DETERMI NA TION. Transfer from DETERMINATION to working in an analytical laboratory will find that the EXPLORATORY is also possible. monograph contains useful information for their daily work. The shown curves can also be exported to other programs, e.g. text processing programs, via the Windows clip board. The curves can also be stored as a file and the list of measuring points can be exported in ASCII format. Practical Voltammetry Metrohm offers the two monographs «Practical Vol tammetry» and «Introduction to Polarography and Voltammetry» for use with the 797 VA Computrace in vocational training. The «Introduction to Polarography and Voltammetry» is presented in compact form on less than 60 pages. The most important current measuring techniques and the different working methods used in polarography and stripping voltammetry are explained. The monograph «Practical Voltammetry» describes 13 experiments for training in voltammetry. It is an ideal comple-ment to «Introduction to Pola ro graphy and Voltammetry». Teachers can select single experiments or decide to do all 797 VA Computrace Manual or automated 10 Even without additional accessories the 797 VA Com putrace is a fully functioning analytical system that meets the highest demands regarding accuracy and sensitivity. An even higher degree of comfort can be achieved with the help of various accessories. Automatic addition of auxiliary solutions with 11 model 800 Dosino dosing systems The voltammetric determination takes place by standard addition or calibration curve und and can be carried out automatically if model 800 Dosinos are used. Connections are available for a maximum of three 800 Dosinos. Of course, all other auxiliary solutions such as buffers or com plexing agents can also be added automatically. Fully automatic analysis of small series of samples with the 863 Compact Autosampler The 863 Compact Autosampler enables fully automatic trace analyses. It is suitable for the precise and reproducible investigation of several samples. The sample rack accommodates a maximum of 18 samples. The built-in peristaltic pump of the 863 Compact Autosampler trans-fers them from the turntable into the measuring cell of the 797 VA Computrace, where they are analyzed. 838 Advanced VA Sample Processor – fully automated CVS analysis In combination with the 838 Advanced VA Sample Processor it is possible to carry out fully automated determinations of organic additives in electroplating baths. A maximum of 56 samples can be analyzed for their suppressor content; the brightener content of up to 28 samples can be determined automatically. Of courese, the 838 Advanced VA Sample Pro cessor is also suitable for trace analysis. Automatic rinsing of the measuring cell with 843 Pump Station Rinsing and emptying the measuring cell after each analysis can be carried out automatically by the 843 Pump Station. This option is available for both manually operated systems and, of course, for VA Computrace systems with an Autosampler. The reproducible and effi-cient rinsing process minimizes carryover and in this way increases the accuracy of the analyses. Autodatabase The analysis data can either be stored individually on the hard disk or in a database using the Autodatabase software with report generator. With Auto database all the data can be assessed at a single glance and individually arranged printouts can be generated. MVA – Metrohm VA systems Complete voltammetry systems – the right 12 MVA systems for the CVS technique system for each application MVA-12 – our recommendation for the The MVA systems are ready-to-use packages, which are determination of additives by CVS customized to suit particular applications. All you have Partly automated 797 VA Computrace system for the to do is connect your package to a PC and you can start com fortable determination of additives by CVS working. Each MVA system comes with all the necessary accessories. MVA accessory kits enhance capabilities of the MVA basic system to suit special applications. MVA systems for voltammetric trace analysis MVA-2 – partly automated routine trace analysis Automatic addition of auxiliary solutions MVA-12 is the standard system for the routine determination of organic additives in single samples without using a sample changer. It enables determinations with hardly any work required on the part of the operator. The automatic addition of auxiliary solutions such as VMS, intercept or standard solutions is carried out by model 800 Dosinos. For the determination of brighteners only MVA-2 is an easy-to-use VA system for the routine analy-the sample has to be added manually; even this step is sis of traces of heavy metals in environmentally relevant automatic when suppressors are being determined. If the samples or in production control. Just add the sample to optional rinsing equipment is used, the measuring vessel the measuring cell from a pipet and start the analysis. can be rinsed automatically after each determination. The rest of the determination takes place automatically. This system is intended for users who require elegant and MVA-13 – fully automatic determination of convenient operation at an attractive price, without hav-organic additives in series of samples ing to use a sample changer. Fully automatic system with sample changer for CVS analysis in the routine laboratory MVA-3 – fully automatic analysis of small series of samples MVA-3 is the optimal 797 VA Computrace system for MVA-13 is our high-end system for determining additives fully automated trace analysis. One or two parameters in electroplating baths. The the samples are provided can be determined in small series of up to 18 samples. automatically by the 838 Advanced VA Sample Processor. The samples are placed on the sample rack of the 863 The suppressor content of a maximum of 56 samples can Compact Autosampler. Transfer and analysis of the sam-be analyzed. When determining brighteners up to 28 ples takes place automatically, controlled by the software samples can be analyzed. The possibility of recalibrating of the 797 VA Computrace. methods within a series of samples guarantees outstanding accuracy. It is also possible to combine different methods in a single measuring procedure. With the aid of the 843 Pump Station the measuring vessel is emptied and rinsed automatically after each sample. MVA accessory kits MVA accessory kits can be used in combination with all 13 Metrohm MVA basic systems to extend their range of applications. MVA-Hg – complete accessory kit for the voltammetric determination of mercury MVA-Hg contains a complete set of electrodes for the determination of mercury by stripping voltammetry according to Application Bulletin 96. It contains all the necessary accessories that are not included in the standard equipment of the Metrohm VA instrument. These comprise a rotating gold electrode, a glassy carbon auxiliary electrode and a reference electrode. MVA-As – complete accessory kit for the voltammetric determination of arsenic MVA-As contains a complete set of electrodes for the determination of arsenic by stripping voltammetry according to Application Bulletin 226. It contains all the necessary accessories that are not included in the standard equipment of the Metrohm VA instrument. These comprise a rotating gold electrode, a glassy carbon auxiliary electrode and a reference electrode. MVA-CVS – complete accessory kit for the determination of additives in electroplating baths by CVS MVA-CVS contains the complete set of electrodes necessary for the determination of additives in electroplating baths by the CVS technique. It contains all the necessary accessories; these include a rotating platinum electrode, a platinum auxiliary electrode and a reference electrode. MVA-CVS allows the determination of organic additives in combination with the systems MVA-1, MVA-2 and MVA-3. 909 UV Digester for the digestion of aqueous samples 909 UV Digester for the elegant sample preparation of water samples with a slight to medium pollution load. It is the ideal addition to all Metrohm VA systems used for testing natural waters or polluted water samples. Quality assurance – no problem with the 797 VA Computrace 14 Access rights Access rights to each program part can be freely de fined for each user. This permits convenient user management. Validation with the GLP Wizard The software automatically checks the validation inter-vals of the analysis system and informs the user. Each report shows whether the validation is still valid. The GLP Wizard guides the user step-by-step through the various validation tests and automatically evaluates their validity. Diagnosis The built-in diagnosis program allows the individual components of the instrument to be checked. This diagnosis is a part of the GLP Wizard, but it can also be carried out independently. Electrode test The electrodes used are automatically checked before each determination. If problems occur then the faulty electrode is identified and the fault shown on the screen. This test can, of course, be triggered manually to check the system. Curve evaluation The software of the 797 VA Computrace automatically evaluates the measured curves and calculates the final result. The algorithm has been completely revised and functions even more reliably. Among other things, the automatic elimination of outliers has been im ple mented. The calculation of the final concentration has also been perfected. This has led to a considerable im provement in the reproducibility and accuracy of results. Certified quality The 779 VA Computrace and its software have been developed and are manufactured according to the highest quality standards, which we guarantee by issuing a quality certificate. The reference electrode and the electrolyte and standard solutions contained in the accessories can be identified by their serial number and are supplied together with an individual certificate. Application Bulletins Metrohm has published about 50 Application Bulletins describing polarographic or voltammetric methods. The exam-15 ples shown here demonstrate just how versatile voltammetry is. Application Bulletin No. Application Bulletin No. Water, wastewater, environmental protection Metals, electroplating Aluminum in water samples 131 Formaldehyde in solutions and plating baths 196 Nitrite in water samples 127 Molybdenum in materials with high iron content 132 Chromium in water samples 116 Thiourea in electroplating baths 192 Cyanide in water samples 110 Iron and manganese in water samples 123 Pharmaceuticals, biology Copper, cobalt, nickel, zinc and iron in foodstuffs Chromium in water samples and biological materials 116 and water samples 114 Cinchocaine in pharmaceuticals 251 Molybdenum in water samples 146 Diazepam in body fluids 250 Nitrate in water samples 70 Folic acid (Vitamin B , Vitamin B ) in mono vitamin 9 c NTA and EDTA in water samples 76 tablets 215 Platinum in environmentally relevant matrices 220 Nitrate in soil, plants, vegetable juices, meat, Mercury in water samples 96 sausages 70 Thallium, antimony, bismuth, iron, copper, vanadium Pyridoxine (Vitamin B ) in vitamin preparations 224 6 in water samples 74 Riboflavin (Vitamin B ) in vitamin preparations 219 2 Zinc, cadmium, lead, copper, thallium, nickel, cobalt Selenium in various matrices 117 in water samples 231 Thiamine (Vitamin B ) in vitamin preparations 218 1 Titanium and uranium 266 Plastics, petrochemicals Food and drinks 4-Carboxybenzaldehyde in terephthalic acid 190 Ascorbic acid (Vitamin C) in foodstuffs and Lead in mineral oil products 50 pharmaceuticals 98 Formaldehyde in plastics and textiles 196 Release of lead and cadmium from from crockery Styrene in Polystyrene and mixed polymers 136 and glassware 105 Cadmium, lead and copper in foodstuffs after General chemistry digestion 113 Lead and tin in various concentration ratios 176 Quinine in drinks and tablets 126 Cadmium, cobalt, copper, iron, nickel, lead, zinc in Cystine and Cysteine simultaneously in biological semiconductors 147 samples 191 Mercury 96 Nicotinamide in fruit juices and vitamin preparations 213 Silver in water, foodstuffs and wastewater 207 Tocopherols (Vitamin E) in edible fats and oils 97 Application Notes The Application Notes present applications in compact form. There are currently about 180 Application Notes in English for voltammetry; these are supplied in printed form together with the instrument. They can also be down-loaded from the Internet under www.metrohm.com. The methods for carrying out these applications are included in the software of the 797 VA Com pu trace. 16 Standards Numerous standards describe voltammetric methods for the determination of traces of metal and organic compounds. A small selection is given below: ISO 713 Zinc – Determination of lead and cadmium contents. Polarographic method ISO 3856-4 Paints and varnishes – Determination of «soluble» metal content. Part 4. Determination of cadmium content. Flame atomic absorption spectrometric method and polarographic method. ISO 6636-1 Fruits, vegetables and derived products. Determination of zinc content. Part 1. Polarographic method. EPA 7063 Arsenic in aqueous samples and extracts by anodic stripping voltammetry (ASV) EPA 7472 Mercury in aqueous samples and extracts by anodic stripping voltammetry (ASV) EPA 7198 Cr(VI) in water by polarography ASTM D 3557-02 Standard test methods for cadmium in water ASTM D 3559-03 Standard test methods for lead in water AOAC 968.16 Fumaric acid in food. Polarographic method. AOAC 972.24 Lead in fish. Polarographic method. AOAC 972.46 Bismuth compounds in drugs AOAC 979.17 Lead in evaporated milk and fruit juice DIN 38406, Teil 16 Determination of 7 metals (Zn, Cd, Pb, Cu, Tl, Ni, Co) in water by voltammetric methods DIN 38413, Teil 5 EDTA and NTA in water samples HMSO/Br.Dept.Env. Metal ions in marine and other waters: Zn, Cd, Pb, Cu, V, Ni, Co, U, Al, Fe Technical specifications 797 VA Computrace Voltammetric measuring stand with built-in potentiostat and galvanostat. 17 Materials Housing: polyurethane hard foam (PUR) with flame protection for fire class UL94VO, CFC-free Base plate and measuring head arm: metal, stove-enameled Working electrodes Multi-Mode Electrode pro (MME pro) 6.1246.120, pneumatically operated as DME, HMDE or SMDE; requires mercury 99.9999% and nitrogen 99.995%, whose pressure must be reduced with a reduction valve to 1.0 ± 0.2 bar (100 ± 20 kPa). Rotating disk electrodes (RDE) with exchangeable electrode tips made from various materials: «Ultra Trace» graphite, glassy carbon, gold, silver, platinum. Reference electrode 6.0728.020 or 6.0728.030 Ag/AgCl/KCl 3 mol/L with 6.1245.010 electrolyte vessel Auxiliary electrodes 6.0343.000 Platinum auxiliary electrode with plastic shaft 6.1241.020 + 6.1247.000 glassy-carbon auxiliary electrode (option) Stirrer Speed 200 to 3’000 min–1 Speed stability ± 5% Material PET Measuring cell Working volume 10...70 mL, 50...150 mL (option: 5 mL...70 mL). Measuring cell with thermostat jacket as option (thermostatting by external instrument – not included) Potentiostat/galvanostat Voltage range ± 5 V Output voltage ± 12 V Current range ± 80 mA Current measurement 7 ranges (10 nA to 10 mA) Sweep rate (CV) < 1 mV/s...3 V/s (at 1 mV resolution) < 1 mV/s...35 V/s (at 10 mV resolution) Power supply Voltage 100...240 V Frequency 50...60 Hz Power consumption 120 VA Temperature Nominal working range 0...45 °C at 20…80% rel. humidity Safety specifications Construction and testing as per IEC 61010/EN 61010/UL 3101-1, protection class 1 Dimensions Width 258 mm Height 245 mm (with cover fully raised approx. 630 mm) Depth 535 mm Weight without accessories 9.7 kg PC requirements For perfect functioning we recommend a Pentium III processor with a clock rate of 1 GHz or higher. Operating system: Microsoft WindowsTM 2000, XP Professional, Vista, or Windows 7 (32 bit versions only) with the following configuration: RAM 256 MB Program files 30 MB Hard disk Min. 200 MB free Graphics adapter/screen Min. resolution 1024 x 768 pixel or higher Printer Any supported by WindowsTM Connection 1 free USB interface Ordering information, options 18 797 VA Computrace 2.797.0010 797 VA Computrace for voltammetric trace analysis. Measuring stand with built-in potentiostat and galvanostat. Three-electrode system with Multi-Mode Electrode pro (MME pro), Ag/AgCl reference electrode and platinum auxiliary electrode. Extendable for rotating disk electrode (RDE). Includes comprehensive accessories for complete setup of measuring place. 2.797.0020 797 VA Computrace for the replacement of older Metrohm voltammetry instruments already equipped with a multi-mode electrode. With fewer accessories than 2.797.0010; the accessories of the existing VA stand are used instead. 2.797.0030 797 VA Computrace for CVS (Cyclic Voltammetric Stripping) for the analysis of additives in electro plating baths. Measuring stand with built-in potentiostat and galvanostat. Three-electrode system with rotating platinum disk electrode (Pt-RDE), Ag/AgCl reference electrode and platinum auxiliary electrode. Extendable for Multi-Mode Electrode pro (MME pro). Includes comprehensive accessories for complete setup of measuring place. Options Automatic solution addition 2.800.0010 800 Dosino 6.3032.120 Dosing Unit 2 mL (glass) for Dosino An 800 Dosino with Dosing Unit must be used for each auxiliary solution to be added. A maximum of three Dosinos can be connected. Sample changers 863 Compact Autosampler 2.863.0020 863 Compact Autosampler (VA) 2.843.0040 843 Pump Station (membrane) 2.843.0140 843 Pump Station (peristaltic) 838 Advanced Sample Processor 2.838.0310 838 Advanced VA Sample Processor 2.843.0040 843 Pump Station (membrane) 19 Accessories for rotating disk electrodes (RDE) 6.5327.000 MVA-Hg Accessory kit for the determination of mercury, for 2.797.0010, 2.797.0020 and 2.797.0030. Complete equipment with gold RDE, Ag/AgCl reference electrode, glassy carbon auxiliary electrode, measuring cell. 6.5327.010 MVA-As Accessory kit for the determination of arsenic, for 2.797.0010, 2.797.0020 and 2.797.0030. Complete equipment with lateral gold RDE, Ag/AgCl reference electrode, glassy carbon auxiliary electrode, measuring cell. 6.5327.020 MVA-CVS Accessory kit for the determination of additives in electroplating baths by CVS (Cyclic Voltammetric Stripping) for 2.797.0010 and 2.797.0020. Complete equipment with platinum RDE 6.1204.610, Ag/AgCl reference electrode, platinum auxiliary electrode, measuring cell. Electrode tips for rotating disk electrode (RDE) 6.1204.180 Ultra trace electrode tip 6.2802.020 Polishing set for ultra trace electrode tip 6.1204.130 Silver electrode tip 6.1204.140 Gold electrode tip 6.1204.150 Lateral gold electrode tip 6.1204.170 Platinum electrode tip 3 mm for CVS 6.1204.190 Platinum electrode tip 1 mm for CVS, glass shaft 6.1204.600 Glassy carbon electrode tip, glass shaft 6.1204.610 Platinum electrode tip 2 mm for CVS, glass shaft Drives for rotating disk electrode (RDE) 6.1204.210 Driving axle for rotating disk electrode (RDE) 6.1204.220 Driving axle for rotating disk electrode (RDE) with mercury contact www.metrohm.com G, CH-9100 Herisau ohm A witzerland by Metr , printed in S SW Subject to change Layout by Ecknauer+Schoch A 8.797.5003EN – 2013-05