product review
The Potentiostat: Electrochemistry’s Utility Player A wide range of choices are available for this tried-and-true instrument. James Smith and Vicki Hinson-Smith
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erforming electrochemical studies without a potentiostat would be like playing baseball without a ball. Modern digital technology has allowed instrument designers to commercialize a variety of robust and user-friendly potentiostats for many diverse applications. Electrochemical studies of single cells have used scanning electrochemical microscopy (Anal. Chem. 2001, 73, 39 A–42 A) with potentiostats that have picoamp sensitivity, whereas studies of axle rod corrosion might require a potentiostat with a 10-amp capability. In the analytical laboratory, innovative software allows a single potentiostat to perform all the standard electrochemical techniques as well as a host of specialized procedures. Potentiostats were last reviewed by Analytical Chemistry five years ago (1997, 69, 369 A–372 A). Since then, the marketplace and product capabilities have changed significantly. Table 1 lists 24 potentiostat manufacturers; although other manufacturers exist, this list is a good starting point for the selection of an instrument. Potentiostats are priced between $2,500 and $25,000, with the average instrument running nearly $10,000. There are many options and accessories available, so the instrument choice should be based on a user’s applications. But remember, a potentiostat may be in service for more than a decade, so don’t limit your options to today’s applications. O C T O B E R 1 , 2 0 0 2 / A N A LY T I C A L C H E M I S T R Y
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product review
Table 1. Selected potentiostat manufacturers. Company
Products
Company
Products
ACM Instruments 125 Station Rd., Cark Grange-over-Sands Cumbria, LA11 7NY United Kingdom +44-15395-59185 www.potentiostat.com
A range of potentiostat zero-resistance ammeters and galvanostats; on Windows systems, up to 128 instruments can be operated from one PC with independent control
BAS Bioanalytical Systems, Inc. 2701 Kent Ave. West Lafayette, IN 47906 (800) 845-4246 www.bioanalytical.com
Offers various instruments, including electroanalytical chemistry PCcontrolled workstations for voltammetry, polarography, and analog potentiostats
ADInstruments 4 Gladstone Rd., Unit 6 Castle Hill, NSW 2154 Australia +61-2-9899-5455 www.adinstruments.com
Bio-Logic Science Instruments SA 1, rue de l’Europe The potentiostat and the picostat (for F-38640-CLAIX high-sensitivity applications) modules France transform the company’s PowerLab into +33-476986831 an electrochemical analyzer www.bio-logic.fr
AMEL srl Via S. Giovanni Battista de la Salle, 4 20132 Milan Italy +39-02-27203060/1 http://amelsrl.com/index.htm
Various potentiostat /galvanostats, including research-grade, low-noise, and high-current instruments
AMMT Advanced Micromachining Tools GmbH Anselm-Feuerbach-Str. 6 D-67227 Frankenthal Germany +49-6233-49600-14 www.ammt.de
AMMT’s MEMS potentiostats are specially designed for silicon micromachining
Arbin Instruments 762 Peach Creek Cut Off Rd. College Station, TX 77845 979-690-2751 www.arbin.com
Arbin’s potentiostats have high-speed pulse capabilities and modified software for various uses, including basic electrochemistry and studies of corrosion, batteries, super-capacitors, and fuel cells
Bank Elektronik-Intelligent Controls GmbH Freiberger Strasse 1 D-38678 Clausthal-Zellerfeld +49-5323-989810 www.bank-ic.de
Founded in 1954 to commercialize the potentiostats designed by Hans Wenking, the company offers a wide range of instruments for the electrochemical workbench
Basically, a potentiostat controls the voltage between a reference electrode and a working electrode. The working electrode is usually the sample under study. When current flows through a reference electrode, the electrode polarizes, and the output voltage changes, so a third electrode—the counter electrode— is usually connected to the working electrode. This arrangement allows the potentiostat to generate an opposing voltage that stops the flow of current through the reference electrode while measuring the current passing between the working electrode and a counter electrode. Many potentiostats can be quickly converted into 540 A
CC Technologies 6141 Avery Rd. Dublin, OH 43016 614-761-1214 www.cctechnologies.com
CC Technologies Laboratories and CC Technologies Canada specialize in materials degradation (metals, polymers, and coatings); the product line includes potentiostats
CH Instruments, Inc. 3700 Tennison Hill Dr. Austin, TX 78738 512-402-0176 www.chinstruments.com
Line of instruments includes the potentiostat, galvanostat, bipotentiostat, and a handheld potentiostat/bipotentiostat
CSEM, Centre Suisse d'Electronique et de Microtechnique SA Jaquet-Droz 1 CH-2007 Neuchâtel Switzerland +41-32-720-5111 www.csem.ch
Offers a low-noise miniaturized potentiostat
Cypress Systems, Inc. 619 East 8th St., Ste. 3E Lawrence, KS 66044 800-235-2436 www.cypresssystems.com
Offers custom-built instruments, battery-powered analog potentiostat microprocessors, controlled analog potentiostats, bipotentiostats, and all-purpose potentiostats
Danntech +27-(0)-11-792-1239 www.danntech.com
Designs and builds electrochemical instruments for process instrumentation products
a galvanostat, which controls the current flow through the sample while measuring the voltage. Electrochemical studies of corrosion, deposition, bulk electrolysis, or electrosynthesis are typically most effective when run with a galvanostat because of the high voltages and currents required.
Choosing a potentiostat Potentiostats integrate many electrochemical techniques with wide dynamic ranges—covering >9 orders of magnitude in time and ranging from picoamps to amperes in current, says Peixin He of CH Instruments. “It is difficult to
A N A LY T I C A L C H E M I S T R Y / O C T O B E R 1 , 2 0 0 2
Designs and manufactures highperformance multichannel potentiostats for research laboratories
optimize . . . an instrument over the full current range,” he explains, “so the operating current should be a first consideration.” Research electrochemical techniques may require rapid scan rates and welldefined waveforms—features that tend to raise the price of a system, notes He. In addition, “A low-noise system is very important for low-current measurements, like those required for electrochemical detection in HPLC or [CE],” he says, “but not as critical for a technique like cyclic voltammetry.” “Most potentiostat manufacturers supply their own software because the
Table 1. Selected potentiostat manufacturers (continued). Company
Products
Company
Products
Eco Chemie B.V. P.O. Box 85163 3508 AD Utrecht The Netherlands +31-30-2893154 www.ecochemie.nl
Manufactures and sells Autolab potentiostats; a member of the Metrohm family of companies
Princeton Applied Research c/o Advanced Measurement Technology, Inc. 801 S. Illinois Ave. Oak Ridge, TN 37831-0895 800-251-9750 www.princetonappliedresearch.com
Offers a range of electrochemical instrumentation for science and industry
Gamry Instruments, Inc. 734 Louis Dr. Warminster, PA 18974 215-682-9330 www.gamry.com
Low-current, high-speed, low-capacitance instrument for microelectrode, sensor, and coatings research; usermodifiable experimental scripts provide flexibility
Radiometer Analytical SAS 72 rue d’Alsace 69627 Villeurbanne CEDEX Lyon, France +33-(0)-478-03-38-38 www.radiometer-analytical.com
VoltaLab is a compact instrument capable of voltammetry and electrochemical impedance spectroscopy, so researchers can mix dc and ac measurements
HEKA Instruments, Inc. 33 Valley Rd. Southboro, MA 01772 866-724-0606 www.heka.com
Ring/disc potentiostat uses two independent working electrodes, which allow the control of ultramicroelectrodes and the performance of generator- and collector-electrode techniques
Solartron Analytical, NA 19408 Park Row, Ste. 320 Houston, TX 77084 281-398-7890 www.solartronanalytical.com
Electrochemical products include potentiostats and a multichannel potentiostat
Metrohm AG Oberdorfstr. 68 CH-9100 Herisau, Switzerland +41-71-353-85-85 www.metrohm.com
Offers a wide range of instrumentation for all fields of chemical ion analysis
A range of electronic systems are available for various industries, including medical research, education, and industrial control and processing
Obbligato Objectives, Inc. 68 Corporate Drive, Ste. 2025 Toronto, Ontario Canada, M1H 3H3 416-650-8164 www.obbligato.com
Focused on the design and production of scientific instruments for college and university teaching and research laboratories
Sycopel Scientific, Ltd. 15 Sedling Rd. Wear Industrial Estate, District 6 Washington, Tyne & Wear NE38 9BZ, United Kingdom +44-(0)-191-4178788 www.sycopel.com
Product line includes scanning potentiostats and a picoammeter/potentiostat for biosensing
Pine Instrument Co. 101 Industrial Dr. Grove City, PA 16127 724-458-6391 www.pineinst.com
Bipotentiostat systems offer the benefits of digital data acquisition while still using a traditional (true) analog sweep generator
World Precision Instruments, Inc. International Trade Center 175 Sarasota Center Blvd. Sarasota, FL 34240-9258 941-371-1003 www.wpiinc.com
machine-level control varies among manufacturers,” says He. Users should look for software that is user friendly and compatible with numerous applications. The software also should provide many graphic, data processing, and data analysis functions.
The future of potentiostats Most industry experts say that potentiostats will become smaller and more portable in the future. They also expect more multichannel systems that will allow several simultaneous analyses controlled by a single computer. Some see the possibility of small arrays of electrodes and potentiostats using lab-on-achip and microfluidic technologies. The electrochemical array detector, which requires a multichannel potentiostat, seems promising in sensor studies. An-
other future development will be the handheld potentiostat, which could be useful for field applications, such as environmental or sensor studies. “There has been a strong demand for microelectrochemical potentiostats in recent years,” says Pierre-Jean Arvers, sales engineer at Arbin Instruments. “Numerous advances in the fields of plating, semiconductors, [and] energy storage have fueled the demand for this type of apparatus for both fundamental and applied research—especially the multichannel systems that allow matrixtype analysis of materials or processes.” Paul Duckworth of AD Instruments predicts that the future will bring greater use of portable electrochemical analyzers, probably with disposable electrodes/cells, for environmental and biomedical applications. Amperometric biosensors
will become more common, and these will be driven with simple meters, such as two-electrode potentiostats, he says. Other variations under development include wireless potentiostats, says Dave Johnson of Pinnacle Technology. His company is working on a wireless multichannel potentiostat that interfaces with a personal computer, as well as very small wireless devices for in vivo measurements. Robert Rodgers of Gamry Instruments adds that the laboratory potentiostat will continue to evolve. “[The] worldwide market for potentiostats will grow,” he projects, “but they will be dedicated, special-purpose, embedded potentiostats.” There are many players, but the electrochemist will be the winner. James Smith and Vicki Hinson-Smith are freelance writers based in Amherst, Mass.
