Difference between revisions of "How to Choose a Potentiostat"

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== Operating Conditions ==
+
== Operating Requirements ==
  
 
When choosing a potentiostat you need to have some idea of the voltage and current limits within which you wish to operate.  
 
When choosing a potentiostat you need to have some idea of the voltage and current limits within which you wish to operate.  
  
−
Most potentiostats offer applied potentials (voltages) of up to ±10 V. Sensitive potentiostats designed four accurate measuring of small currents (nA or less) typically offer maximum currents of up to 10 mA. Large current potentiostats (1 A or more) are usually do not provide small current ranges, or else they are very expensive, or require 'headstage' current amplifiers.
+
Most potentiostats offer applied potentials (voltages) of up to ±10 V. Sensitive potentiostats designed for accurate measuring of small currents (nanoamperes or less) typically offer maximum currents of up to 10 mA. Large current potentiostats (1 A or more) often do not provide small current ranges (less than microamperes), or else they are very expensive, or require 'headstage' current amplifiers. Analytical chemists usually require a mid-range potentiostat (nanoamperes to 100 mA or so). Electrosynthesis experiments usually require currents in excess of 10 mA, and a maximum current of 1 A, or more, is often useful if you need to generate a few grams of material in a reasonable timeframe.
  
 
== Number of Electrodes ==
 
== Number of Electrodes ==
Line 13: Line 13:
 
=== Two-Electrode Potentiostats ===
 
=== Two-Electrode Potentiostats ===
  
−
A two-electrode potentiostat uses a working and counter electrode. A disadvantage of this arrangement is that if the electrodes are further apart then the resistance between them increases and the current decreases, so reproducible results can be hard to achieve if electrode surface area, or separation distance, varies. Polarographic oxygen electrode meters are examples of two-electrode potentiostats.   eDAQ two-electrode potentiostats are below:
+
A two-electrode potentiostat uses a working and counter electrode. A disadvantage of this arrangement is that if the electrodes are further apart than the resistance between them increases and the current decreases. Thus reproducible results can be hard to achieve if electrode surface area, or separation distance, varies. Polarographic oxygen, peroxide, and nitric oxide electrode meters are all examples of two-electrode potentiostats. Note that in each of these cases the electrodes (anode and cathode) are usually built into a single probe body so that the orientation and distance between the electrodes is held constant from one experiment to the next.
 +
 
 +
eDAQ two-electrode potentiostats are:
  
 
: [http://www.edaq.com/EPU352 EPU352 USB Biosensor isoPod]
 
: [http://www.edaq.com/EPU352 EPU352 USB Biosensor isoPod]
−
: [http://www.edaq.com/EP352 EP352 Biosensor Isopod] (for use with eCorder systems)
+
: [http://www.edaq.com/EPU354 EPU354 USB dO<sub>2</sub> isoPod]
 +
: [http://www.edaq.com/EPU355 EPU355 USB Nitric Oxide isoPod]
  
−
Other potentiostats can often be used as two-electrode potentiostats by connecting the voltage sensing (reference electrode) inputs to the appropriate current passing (auxiliary or working electrode) inputs, see below.
+
: [http://www.edaq.com/EP352 EP352 Biosensor isoPod] for use with e-corder systems
 +
: [http://www.edaq.com/EP354 EP354 USB dO<sub>2</sub> isoPod] for use with e-corder systems
 +
: [http://www.edaq.com/EP355 EP355 USB Nitric Oxide isoPod] for use with e-corder systems
 +
 
 +
Three- and four-electrode potentiostats can often be used as two-electrode potentiostats by connecting the voltage sensing (reference electrode) inputs to the appropriate current passing (auxiliary or working electrode) inputs, see below.
  
 
=== Three-Electrode Potentiostats ===
 
=== Three-Electrode Potentiostats ===
  
−
This is typically what people mean when they say a 'potentiostat'. With a  'three-electrode' potentiostat the potential is monitored between reference and working electrodes that are in close proximity, while the potential of a relatively distant auxiliary electrode is adjusted. The current flow is measured between the working and auxiliary electrodes. This has the advantage that no current actually passes through the reference electrode, so there is no electrolytic reaction occurring there, and thus the reference electrode potential can remain constant throughout the experiment. A consequence of this arrangement is that the potential between the working and auxiliary electrodes (the 'compliance' potential, which is usually not reported) can be many times the applied potential (depending on electrolyte resistance and distance between the electrodes). By attaching the potentiostat reference and auxiliary inputs to the same 'counter' electrode a three-electrode potentiostat can be used as a two-electrode potentiostat.  The following eDAQ Potentiostats below can be operated as 3-electrode potentiostats.
+
This is typically what people mean when they say a 'potentiostat'. With a  'three-electrode' potentiostat the potential is monitored between reference and working electrodes that are in close proximity, while the potential of a relatively distant auxiliary electrode is adjusted. The current flow is measured between the working and auxiliary electrodes. This has the advantage that no current actually passes through the reference electrode, so there is no electrolytic reaction occurring there, and thus the reference electrode potential can remain constant throughout the experiment. A consequence of this arrangement is that the potential between the working and auxiliary electrodes (the 'compliance' potential, which is usually not reported) can be many times the applied potential (depending on electrolyte resistance and distance between the electrodes). By attaching the potentiostat reference and auxiliary inputs to the same 'counter' electrode, a three-electrode potentiostat can be used as a two-electrode potentiostat.  The following eDAQ Potentiostats below can be operated as three-electrode potentiostats.
  
−
: [http://www.edaq.com/EA163 EA163 Potentiostat]
 
 
: [http://www.edaq.com/ER466 ER466 Integrated Potentiostat]
 
: [http://www.edaq.com/ER466 ER466 Integrated Potentiostat]
 +
: [http://www.edaq.com/ER467 ER467 High Current Potentiostat]
 +
: [http://www.edaq.com/EA163 EA163 Potentiostat]
 
: [http://www.edaq.com/ER466 EA164 QuadStat]
 
: [http://www.edaq.com/ER466 EA164 QuadStat]
 
: [http://www.edaq.com/EA362 EA362 Dual Picostat]
 
: [http://www.edaq.com/EA362 EA362 Dual Picostat]
Line 31: Line 39:
 
=== Bipotentiostats and Multiple Working Electrodes ===
 
=== Bipotentiostats and Multiple Working Electrodes ===
  
−
A bipotentiostat system features a reference and auxiliary electrode, and two working electrodes, whose potentials can be independently adjusted while the current flowing through them is monitored. This principle can be extended to any number of working electrodes, for example the [http://www.edaq.com/EA164 EA164 QuadStat] controls up to four working electrodes. Typically the potential between the reference and first working electrode is controlled and the potentials of subsequent working electrodes are offset relative to the first electrode to achieve the desired effect. These potentiostats are often used in 'electrochemical nose' systems.
+
A bipotentiostat system features a reference and auxiliary electrode, and two working electrodes, whose potentials can be independently adjusted while the current flowing through them is monitored. This principle can be extended to any number of working electrodes, for example the
 +
: [http://www.edaq.com/EA164 EA164 QuadStat] controls up to four working electrodes, while the
 +
: [http://www.edaq.com/EA362 EA362 Dual Picostat] is a bipotentiostat (ie can control up to two working electrodes).  
 +
 
 +
Typically the potential between the reference and first working electrode is controlled and the potentials of subsequent working electrodes are offset relative to the first electrode to achieve the desired effect. These potentiostats are often used in 'electrochemical nose' systems.
  
 
=== Four-Electrode Potentiostats ===
 
=== Four-Electrode Potentiostats ===
  
−
The term '4-electrode potentiostat' is usually reserved for a device with two reference ('voltage sensing') electrodes and two working ('current passing') electrodes. The potential difference between the two reference electrodes is controlled while the current flow between the two working electrodes is monitored. These potentiostats are commonly used to measure the current flow across a membrane separating two compartments, or across the interface of two immiscible solvents (an ITES experiment). The EA362 Dual Picostat can be used in 4-electrode mode. The EA167 Dual Reference Adaptor can convert most three electrode potentiostats into a 4-electrode system.
+
The term 'four-electrode potentiostat' is usually reserved for a device with two reference ('voltage sensing') electrodes and two working ('current passing') electrodes. The potential difference between the two reference electrodes is controlled while the current flow between the two working electrodes is monitored. These potentiostats are commonly used to measure the current flow across a membrane separating two compartments, or across the interface of two immiscible solvents (an [http://en.wikipedia.org/wiki/ITIES ITIES] experiment). The  
−
Galvanostats
+
: [http://www.edaq.com/ER467 ER467 High Current Potentiostat] is a 4-electrode system with one working, one counter, and two reference electrodes for the measurement of currents across membranes (4-electrode voltage clamp), or the interface between two immiscible electrolyte solutions (ITES).
 +
: [http://www.edaq.com/EA362 EA362 Dual Picostat] can be used in four-electrode mode  
 +
: [http://www.edaq.com/EA167 EA167 Dual Reference Adaptor] can convert most three electrode potentiostats into a four-electrode system.
  
 
== Galvanostats ==
 
== Galvanostats ==
Line 42: Line 56:
 
Some potentiostats can be operated as galvanostats. In this case the current flow is controlled while the potential is monitored.  Note that you cannot control both the current and the potential simultaneously unless you have a variable load! eDAQ potentiostats that work as galvanostats are:
 
Some potentiostats can be operated as galvanostats. In this case the current flow is controlled while the potential is monitored.  Note that you cannot control both the current and the potential simultaneously unless you have a variable load! eDAQ potentiostats that work as galvanostats are:
  
−
: [http://www.edaq.com/EA163 EA163 Potentiostat]
+
: [http://www.edaq.com/ER467 ER467 High Current Potentiostat]
 
: [http://www.edaq.com/ER466 ER466 Integrated Potentiostat]
 
: [http://www.edaq.com/ER466 ER466 Integrated Potentiostat]
 +
: [http://www.edaq.com/EA163 EA163 Potentiostat] (as well as its EA161 and EA160 predecessors)
  
 
== Software ==
 
== Software ==
Line 49: Line 64:
 
Stand-alone potentiostats can be operated without a computer, and while there are a few models on the market, most modern potentiostats are operated via software from a computer.
 
Stand-alone potentiostats can be operated without a computer, and while there are a few models on the market, most modern potentiostats are operated via software from a computer.
  
−
Check that the software offers the electrochemistry techniques you require, or whether you need extra, optional software. Often overlooked is the ease of operation of the software, and especially how the software saves experiments to the computer hard disk. For example, if each separate experiment is saved as a separate file then you will soon have hundreds of files on the computer hard disk to sort through every time you need to review a result. Some software offers library functions to do this while other software can multiple experiment into a single disk file for ease of access.
+
Check that the software offers the [https://www.edaq.com/wiki/Software_for_Electrochemistry_Techniques electrochemistry techniques] you require, or whether you need extra, optional software. Often overlooked is the ease of operation of the software, and especially how the software saves experiments to the computer hard disk. For example, if each separate experiment is saved as a separate file then you will soon have hundreds of files on the computer hard disk to sort through every time you need to review a result. Some software offers library functions to do this while other software can multiple experiment into a single disk file for ease of access.
  
 
== eDAQ Potentiostat Systems ==
 
== eDAQ Potentiostat Systems ==
 +
 +
eDAQ offer a variety of potentiostat systems for a variety of experimental requirements. The table below gives an indication of these.
  
 
{| class="wikitable"
 
{| class="wikitable"
 
! width="50"|Name
 
! width="50"|Name
 
! width="250"|[http://www.edaq.com/ER461 EChem Startup System]
 
! width="250"|[http://www.edaq.com/ER461 EChem Startup System]
−
! width="250"|[http://www.edaq.com/EA163 EChem Startup System with Fast Potentiostat]
+
! width="250"|[http://www.edaq.com/EA163 EChem Startup System with High Bandwidth Potentiostat]
 
! width="250"|[http://www.edaq.com/EA362 Dual Picostat Bundle]
 
! width="250"|[http://www.edaq.com/EA362 Dual Picostat Bundle]
−
! width="250"|[http://www.edaq.com/EA164 QuadStat EChem System Bundle]
+
! width="250"|[http://www.edaq.com/ER7005 QuadStat Bundle]
−
! width="250"|[http://www.edaq.com/ERZ101 Advanced Electrochemistry System]
+
 
|-
 
|-
−
| Product Code || align="center" | ER461 || align="center" | ER7163 || align="center" | ER7162 || align="center" | ER864 || align="center" | ERZ101
+
| Product Code || align="center" | ER461CE || align="center" | ER7163 || align="center" | ER7162 || align="center" | ER7005
 
|- valign="top"
 
|- valign="top"
 
| Products Included ||  
 
| Products Included ||  
Line 84: Line 100:
 
* [http://www.edaq.com/ED821 ED821]
 
* [http://www.edaq.com/ED821 ED821]
 
* [http://www.edaq.com/ER175 ER175]
 
* [http://www.edaq.com/ER175 ER175]
−
* [http://www.edaq.com/ES500 ES500]
 
−
||
 
−
* [http://www.edaq.com/ERZ100 ERZ100]
 
−
* [http://www.edaq.com/EA163 EA163]
 
−
* [http://www.edaq.com/ED410 ED410]
 
−
* [http://www.edaq.com/ET014 ET014]
 
−
* [http://www.edaq.com/ES260 ES260]
 
 
* [http://www.edaq.com/ES500 ES500]
 
* [http://www.edaq.com/ES500 ES500]
 
|-
 
|-
−
| Number of Channels || align="center" | 1 || align="center" | 1 || align="center" | 2 (bipotentiostat) || align="center" | 4 (quadpotentiostat) || align="center" | 1
+
| Number of Channels || align="center" | 1 || align="center" | 1 || align="center" | 2 (bipotentiostat) || align="center" | 4 (quadpotentiostat)
 
|- valign="top"
 
|- valign="top"
 
| Modes
 
| Modes
Line 112: Line 121:
 
* Potentiostat
 
* Potentiostat
 
* ZRA
 
* ZRA
−
||
 
−
* Potentiostat
 
−
* Galvanostat
 
−
* ZRA
 
−
* High Z
 
 
|- valign="top"
 
|- valign="top"
 
| Current Ranges
 
| Current Ranges
 
||
 
||
−
<small>±100, 50, 20, 10, 5, 2, 1 mA
+
<small>±100*, 50, 20, 10, 5, 2, 1 mA
  
 
±500, 200, 100, 50, 20, 10, 5, 2, 1 µA
 
±500, 200, 100, 50, 20, 10, 5, 2, 1 µA
  
 
±500, 200, 100, 50, 20 nA</small>
 
±500, 200, 100, 50, 20 nA</small>
 +
 +
<small>
 +
-* The [http://www.edaq.com/ER467 ER467] has a maximum current of 1 amp.
 +
</small>
 
||
 
||
 
<small>±100, 50, 20, 10, 5, 2, 1 mA
 
<small>±100, 50, 20, 10, 5, 2, 1 mA
Line 150: Line 158:
  
 
</small>
 
</small>
−
 
−
||
 
−
<small>±100, 50, 20, 10, 5, 2, 1 mA
 
−
 
−
±500, 200, 100, 50, 20, 10, 5, 2, 1 µA
 
−
 
−
±500, 200, 100, 50, 20 nA</small>
 
 
|- valign="top"
 
|- valign="top"
 
| Electrochemistry Techniques
 
| Electrochemistry Techniques
 
||
 
||
−
CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*
+
<small>
 +
CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, PSA, CTPE, CCE, electrosynthesis, RDE*, QCM*, OCP/OCV, CCC
 +
</small>
 
||
 
||
−
CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*
+
<small>
 +
CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*, OCP/OCV, CCC
 +
</small>
 
||
 
||
−
CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*
+
<small>
 +
CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*, CCC
 +
</small>
 
||
 
||
−
CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*
+
<small>
 +
CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*, CCC
  
 
CV and LSV with Chart software
 
CV and LSV with Chart software
−
||
+
</small>
−
EIS Electrochemical Impedance Spectroscopy
+
−
 
+
−
CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*
+
 
|- valign="top"
 
|- valign="top"
 
| Typical Applications
 
| Typical Applications
 
||
 
||
 +
<small>
 
* Compound characterization
 
* Compound characterization
 
* Electrolysis
 
* Electrolysis
Line 181: Line 187:
 
* Kinetics
 
* Kinetics
 
* [http://www.edaq.com/biosensors Sensors]
 
* [http://www.edaq.com/biosensors Sensors]
 +
</small>
 
||
 
||
 +
<small>
 
* Compound characterization
 
* Compound characterization
 
* Electrolysis
 
* Electrolysis
Line 187: Line 195:
 
* Kinetics
 
* Kinetics
 
* [http://www.edaq.com/biosensors Sensors]
 
* [http://www.edaq.com/biosensors Sensors]
 +
</small>
 
||
 
||
 +
<small>
 
* Carbon fiber and ultramicroelectrodes
 
* Carbon fiber and ultramicroelectrodes
 
* In vivo monitoring of dopamine
 
* In vivo monitoring of dopamine
 
* Ionic transport across membranes or immiscible interfaces
 
* Ionic transport across membranes or immiscible interfaces
 
* Monitor [http://www.edaq.com/dissolved-oxygen dissolved oxygen], [http://www.edaq.com/nitric-oxide nitric oxide], etc.
 
* Monitor [http://www.edaq.com/dissolved-oxygen dissolved oxygen], [http://www.edaq.com/nitric-oxide nitric oxide], etc.
 +
</small>
 
||
 
||
 +
<small>
 
* [http://www.edaq.com/biosensors Simultaneous monitoring of sensors]
 
* [http://www.edaq.com/biosensors Simultaneous monitoring of sensors]
 
* Bipotentiostat operation
 
* Bipotentiostat operation
 
* [http://www.edaq.com/neurochemistry Neurochemistry]
 
* [http://www.edaq.com/neurochemistry Neurochemistry]
−
||
+
</small>
−
* Surface corrosion
+
−
* Membrane structure and permeability
+
−
* Self-assembled monolayers (SAMs)
+
−
* [http://www.edaq.com/biosensors Sensors]
+
−
* Epitaxial layers
+
−
* Interfacial ion transport
+
−
* [http://www.edaq.com/solar-and-fuel-cells Battery and fuel cell]
+
−
* Biocompatible surfaces
+
 
|}
 
|}
  
Line 211: Line 215:
 
CV cyclic voltammetry; LSV linear sweep voltammetry; DPV differential pulse voltammetry; SWV square wave voltammetry; NPV  normal pulse voltammetry; RPV reverse pulse voltammetry; LSSV linear sweep stripping voltammetry; DPSV differential pulse stripping voltammetry; SWSV square wave stripping voltammetry; NPSV normal pulse stripping voltammetry; MPV multipulse voltammetry; DPA differential pulse amperometry and double pulse amperometry; CPE constant potential electrolysis, DNPV differential normal pulse amperometry; DBPV double pulse voltammetry;
 
CV cyclic voltammetry; LSV linear sweep voltammetry; DPV differential pulse voltammetry; SWV square wave voltammetry; NPV  normal pulse voltammetry; RPV reverse pulse voltammetry; LSSV linear sweep stripping voltammetry; DPSV differential pulse stripping voltammetry; SWSV square wave stripping voltammetry; NPSV normal pulse stripping voltammetry; MPV multipulse voltammetry; DPA differential pulse amperometry and double pulse amperometry; CPE constant potential electrolysis, DNPV differential normal pulse amperometry; DBPV double pulse voltammetry;
  
−
CNA chronoamperometry; CNC chronocoulometry; CNP chronopotentiometry;
+
CNA chronoamperometry; CNC chronocoulometry; CNP chronopotentiometry; [https://www.edaq.com/wiki/Potentiometric_Stripping_Analysis_(PSA) PSA potentiometric stripping analysis]; CTPE controlled potential electrolysis; CCE controlled current electrolysis; RDE rotating disk electrode*; QCM quartz crystal microbalance*; OCP/OCV open circuit potential/open circuit voltage (High Z mode, high impedance voltmeter); CCC closed circuit current (ZRA mode, zero resistance ammeter)
−
CTPE controlled potential electrolysis; CCE controlled current electrolysis; RDE rotating disk electrode*; QCM quartz crystal microbalance*  
+
  
 
RDE and QCM require additional third party equipment*
 
RDE and QCM require additional third party equipment*

Latest revision as of 15:14, 12 February 2020

A potentiostat is a device that controls the potential between a pair of electrodes whilst measuring the resulting current flow.


Operating Requirements

When choosing a potentiostat you need to have some idea of the voltage and current limits within which you wish to operate.

Most potentiostats offer applied potentials (voltages) of up to ±10 V. Sensitive potentiostats designed for accurate measuring of small currents (nanoamperes or less) typically offer maximum currents of up to 10 mA. Large current potentiostats (1 A or more) often do not provide small current ranges (less than microamperes), or else they are very expensive, or require 'headstage' current amplifiers. Analytical chemists usually require a mid-range potentiostat (nanoamperes to 100 mA or so). Electrosynthesis experiments usually require currents in excess of 10 mA, and a maximum current of 1 A, or more, is often useful if you need to generate a few grams of material in a reasonable timeframe.

Number of Electrodes

Two-Electrode Potentiostats

A two-electrode potentiostat uses a working and counter electrode. A disadvantage of this arrangement is that if the electrodes are further apart than the resistance between them increases and the current decreases. Thus reproducible results can be hard to achieve if electrode surface area, or separation distance, varies. Polarographic oxygen, peroxide, and nitric oxide electrode meters are all examples of two-electrode potentiostats. Note that in each of these cases the electrodes (anode and cathode) are usually built into a single probe body so that the orientation and distance between the electrodes is held constant from one experiment to the next.

eDAQ two-electrode potentiostats are:

EPU352 USB Biosensor isoPod
EPU354 USB dO2 isoPod
EPU355 USB Nitric Oxide isoPod
EP352 Biosensor isoPod for use with e-corder systems
EP354 USB dO2 isoPod for use with e-corder systems
EP355 USB Nitric Oxide isoPod for use with e-corder systems

Three- and four-electrode potentiostats can often be used as two-electrode potentiostats by connecting the voltage sensing (reference electrode) inputs to the appropriate current passing (auxiliary or working electrode) inputs, see below.

Three-Electrode Potentiostats

This is typically what people mean when they say a 'potentiostat'. With a 'three-electrode' potentiostat the potential is monitored between reference and working electrodes that are in close proximity, while the potential of a relatively distant auxiliary electrode is adjusted. The current flow is measured between the working and auxiliary electrodes. This has the advantage that no current actually passes through the reference electrode, so there is no electrolytic reaction occurring there, and thus the reference electrode potential can remain constant throughout the experiment. A consequence of this arrangement is that the potential between the working and auxiliary electrodes (the 'compliance' potential, which is usually not reported) can be many times the applied potential (depending on electrolyte resistance and distance between the electrodes). By attaching the potentiostat reference and auxiliary inputs to the same 'counter' electrode, a three-electrode potentiostat can be used as a two-electrode potentiostat. The following eDAQ Potentiostats below can be operated as three-electrode potentiostats.

ER466 Integrated Potentiostat
ER467 High Current Potentiostat
EA163 Potentiostat
EA164 QuadStat
EA362 Dual Picostat

Bipotentiostats and Multiple Working Electrodes

A bipotentiostat system features a reference and auxiliary electrode, and two working electrodes, whose potentials can be independently adjusted while the current flowing through them is monitored. This principle can be extended to any number of working electrodes, for example the

EA164 QuadStat controls up to four working electrodes, while the
EA362 Dual Picostat is a bipotentiostat (ie can control up to two working electrodes).

Typically the potential between the reference and first working electrode is controlled and the potentials of subsequent working electrodes are offset relative to the first electrode to achieve the desired effect. These potentiostats are often used in 'electrochemical nose' systems.

Four-Electrode Potentiostats

The term 'four-electrode potentiostat' is usually reserved for a device with two reference ('voltage sensing') electrodes and two working ('current passing') electrodes. The potential difference between the two reference electrodes is controlled while the current flow between the two working electrodes is monitored. These potentiostats are commonly used to measure the current flow across a membrane separating two compartments, or across the interface of two immiscible solvents (an ITIES experiment). The

ER467 High Current Potentiostat is a 4-electrode system with one working, one counter, and two reference electrodes for the measurement of currents across membranes (4-electrode voltage clamp), or the interface between two immiscible electrolyte solutions (ITES).
EA362 Dual Picostat can be used in four-electrode mode
EA167 Dual Reference Adaptor can convert most three electrode potentiostats into a four-electrode system.

Galvanostats

Some potentiostats can be operated as galvanostats. In this case the current flow is controlled while the potential is monitored. Note that you cannot control both the current and the potential simultaneously unless you have a variable load! eDAQ potentiostats that work as galvanostats are:

ER467 High Current Potentiostat
ER466 Integrated Potentiostat
EA163 Potentiostat (as well as its EA161 and EA160 predecessors)

Software

Stand-alone potentiostats can be operated without a computer, and while there are a few models on the market, most modern potentiostats are operated via software from a computer.

Check that the software offers the electrochemistry techniques you require, or whether you need extra, optional software. Often overlooked is the ease of operation of the software, and especially how the software saves experiments to the computer hard disk. For example, if each separate experiment is saved as a separate file then you will soon have hundreds of files on the computer hard disk to sort through every time you need to review a result. Some software offers library functions to do this while other software can multiple experiment into a single disk file for ease of access.

eDAQ Potentiostat Systems

eDAQ offer a variety of potentiostat systems for a variety of experimental requirements. The table below gives an indication of these.

Name EChem Startup System EChem Startup System with High Bandwidth Potentiostat Dual Picostat Bundle QuadStat Bundle
Product Code ER461CE ER7163 ER7162 ER7005
Products Included
Number of Channels 1 1 2 (bipotentiostat) 4 (quadpotentiostat)
Modes
  • Potentiostat
  • Galvanostat
  • ZRA
  • High Z
  • Potentiostat
  • Galvanostat
  • ZRA
  • High Z
  • Potentiostat
  • ZRA
  • Potentiostat
  • ZRA
Current Ranges

±100*, 50, 20, 10, 5, 2, 1 mA

±500, 200, 100, 50, 20, 10, 5, 2, 1 µA

±500, 200, 100, 50, 20 nA

-* The ER467 has a maximum current of 1 amp.

±100, 50, 20, 10, 5, 2, 1 mA

±500, 200, 100, 50, 20, 10, 5, 2, 1 µA

±500, 200, 100, 50, 20 nA


±10, 5, 2, 1 µA

±500, 200, 100, 50, 20, 10, 5, 2, 1 nA

±500, 200, 100, 50, 20, 10, 5, 2, 1 pA

±10, 5, 2, 1 mA

±500, 200, 100, 50, 20, 10, 5, 2, 1 µA

±500, 200, 100, 50, 20, 10, 5, 2, 1 nA

±500, 200 pA

Electrochemistry Techniques

CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, PSA, CTPE, CCE, electrosynthesis, RDE*, QCM*, OCP/OCV, CCC

CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*, OCP/OCV, CCC

CV, LSV, DPV, SWV, NPV, RPV, LSSV, DPSV, SWSV, NPSV, MPV, DPA, CPE, DNPV, DBPV, CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*, CCC

CNA, CNC, CNP, CTPE, CCE, electrosynthesis, RDE*, QCM*, CCC

CV and LSV with Chart software

Typical Applications

  • Compound characterization
  • Electrolysis
  • Analytical chemistry
  • Kinetics
  • Sensors

  • Compound characterization
  • Electrolysis
  • Analytical chemistry
  • Kinetics
  • Sensors

  • Carbon fiber and ultramicroelectrodes
  • In vivo monitoring of dopamine
  • Ionic transport across membranes or immiscible interfaces
  • Monitor dissolved oxygen, nitric oxide, etc.

Acronyms for Electrochemistry Techniques

CV cyclic voltammetry; LSV linear sweep voltammetry; DPV differential pulse voltammetry; SWV square wave voltammetry; NPV normal pulse voltammetry; RPV reverse pulse voltammetry; LSSV linear sweep stripping voltammetry; DPSV differential pulse stripping voltammetry; SWSV square wave stripping voltammetry; NPSV normal pulse stripping voltammetry; MPV multipulse voltammetry; DPA differential pulse amperometry and double pulse amperometry; CPE constant potential electrolysis, DNPV differential normal pulse amperometry; DBPV double pulse voltammetry;

CNA chronoamperometry; CNC chronocoulometry; CNP chronopotentiometry; PSA potentiometric stripping analysis; CTPE controlled potential electrolysis; CCE controlled current electrolysis; RDE rotating disk electrode*; QCM quartz crystal microbalance*; OCP/OCV open circuit potential/open circuit voltage (High Z mode, high impedance voltmeter); CCC closed circuit current (ZRA mode, zero resistance ammeter)

RDE and QCM require additional third party equipment*

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