BiPotentiostat

A BiPotentiostat is a potentiostat with two working electrodes, one counter electrode, and one reference electrode. The two working electrodes can be operated and monitored exactly simultaneously.

A regular potentiostat, or monopotentiostat to emphasize that it is just one working electrode, has three types of electrodes:

Reference electrode: This electrode has a constant OCP (Open Circuit Potential) and is the reference point of the potentiostat.
Working electrode: This is the electrode where the reaction of interest occurs.
Counter or auxiliary electrode: This is the electrode that completes the circuit with the working electrode, so a current can flow.

The difference between a normal potentiostat and a BiPotentiostat is the number of working electrodes. A normal potentiostat has one working electrode, while a BiPotentistat has two. The capabilities of the BiPot, which is short for BiPotentiostat, differ per instrument.

What do the working electrodes do in a BiPotentiostat?

Working electrode 1 performs one of the techniques listed at the bottom of this page while working electrode 2 can have its own constant potential or follow the potential of working electrode 1. In the latter case, you can have a potential offset between working electrodes 1 and 2 keeping the potential difference between both electrodes constant.

Why use a BiPotentiostat?

Application examples:

Second electrode as blank or similar in the same cell for comparison
Detection of the reaction product of the disc electrode at the ring of a RRDE (Rotating Ring Disc Electrode)
Polarization of the surface during scanning electrochemical microscopy (SECM)
Control of a transistor’s gate voltage (ISFET)

Available Techniques

Which electrochemical techniques can be performed with a BiPotentiostat?

	Nexus	(Multi)PalmSens4	EmStat Pico / Sensit BT / Wearable
Linear Sweep Voltammetry (LSV)
Cyclic Voltammetry (CV)
Chronoamperometry (CA)
Chronocoulometry (CC)
Multistep Amperometry (MA)
Square Wave Voltammetry (SWV)¹

¹ The pulsed techniques are available only in the offset mode. This means that the WE2 can only apply a pulse following the WE1.

Compatible Devices

Which PalmSens instruments have a BiPotentiostat?

Nexus, optional module
PalmSens4, optional module
MultiPalmSens4, optional module per channel
Sensit BT SNS (cabled) version, standard
Sensit BT SPE, only under special request

The BiPot module can be controlled with PSTrace for Windows and PStouch for Android.

BiPot Specifications

BiPotentiostat modules specifications for each instrument model

	Nexus	(Multi)PalmSens4	EmStat Pico / Sensit BT / Wearable
dc-potential range	±5 V	±5 V	-1.2 to +2 V ²
applied dc-potential resolution	153 µV (16-bit)	153 µV (16-bit)	537 μV (16-bit)
compliance voltage	±5 V	±5 V	-2.0 to +2.3 V ²
dc-offset error	≤ 0.1% ±1 mV offset	≤ 0.1% ±1 mV offset	≤ 0.1% ±150 µV offset
applied potential accuracy	≤ 0.1%	≤ 0.1%	< 0.2%
current ranges	100 pA to 10 mA (8 ranges)	1 nA to 10 mA (8 ranges)	100 nA to 1 mA (11 ranges)
maximum measured current	45 mA	i(WE1) + i(WE2) < 30 mA	± 3 mA
measured current resolution	0.0038% of current range	0.005% of current range	0.006% of current range
current accuracy	≤ 0.1% at Full Scale Range all with additional 0.2% offset error	≤ 0.1% at Full Scale Range all with additional 0.2% offset error	< 0.5% of current ±0.1% of range
connection	Additional (yellow) connector for WE2	Additional (yellow) connector for WE2	Additional (yellow) connector for WE2
power		Comes with additional USB Y-cable for extra power