A BiPotentiostat is a potentiostat with two working electrodes. One electrode is the counter electrode and the other is the reference electrode. The two working electrodes can be operated and monitored exactly simultaneously. A Bipotentiostat is sometimes called a BiPot. The capabilities of the BiPot channel differ per instrument.
Each potentiostat has three types of electrodes:
- Reference electrode: This is an electrode held at a known potential with high stability. Generally, it is grounded and held at 0 potential.
- 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
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.
What do the working electrodes do in a BiPotentiostat?
Working electrode 1 performs one of the techniques listed on the bottom of this page, while working electrode 2 can have its own constant potential or follow the potential of working electrode 1. The reference electrode then only records the potential of the electrolyte and does not conduct current.
In this way, one can measure the working electrode or even the counter electrode separately. In the latter case, a potential offset can also be added.
Why use a BiPotentiostat?
- 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 gate voltage transistors (ISFET)
What electrochemical techniques can be performed with a BiPotentiostat?
In BiPotentiostat mode, the PalmSens 4 supports the following four techniques:
- Linear Sweep Voltammetry (LSV)
- Cyclic Voltammetry (CV)
- Chronoamperometry (CA)
- Multistep Amperometry (MA)
The Sensit BT supports in BiPotentiostat-mode the following techniques:
What PalmSens instruments have a BiPotentiostat?
The Sensit BT.SNS comes with BiPot channel. The PalmSens4 is available with BiPot module for all PalmSens4 configurations. The BiPot module can be controlled with PSTrace for Windows and PStouch for Android.
|BiPot specifications PalmSens4|
|dc-potential range||±5 V|
|dc-potential resolution||153 µV|
|dc-offset error||≤ 0.1% ±1 mV offset|
|current ranges||100 pA to 10 mA (9 ranges)|
|maximum measured current||i(WE1) + i(WE2) < 30 mA|
|current resolution||0.005% of current range (5 fA on 100 pA range) 0.0025% of 10mA range|
|current accuracy||≤ 0.1% at Full Scale Range all with additional 0.2% offset error|
|connection||Comes with a sensor cable with an additional (yellow) connector for WE2|
|power||Comes with additional USB Y-cable for extra power|
|BiPot specifications Sensit BT.SNS|
|Full dc-potential range||-1.2 to +2 V|
|Dynamic dc-potential range ||2.2 V|
|Compliance voltage||-2.0 to +2.3 V |
|Maximum current||± 3 mA|
|Max. data acquisition rate||400k|
 The dynamic range is the range that can be covered during a single scan within the full potential range. For example; a linear scan can start at -1.5 V and end at 1.1 V or vice versa, covering 2.6 V dynamic range.
 The compliance voltage is the maximum potential between Working and Counter electrode and depends on the selected mode.