What is a Cyclic Voltammeter?Cyclic Voltammeter (CV) is a versatile electroanalytical instrument that monitors the redox behaviour of chemical and biochemical species in solution.
Why are we buiding a low-cost CV?Now although there are many projects in Hwa Chong Science Research Center that can benefit from the data obtained with the use of CV, a commercial CV can cost up to SGD 20000, so it is currently not cost effective for school use. And thus, there is a need for us to build a low-cost CV.
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Structure of our CV
Basically a CV consists of three parts: the electrochemical cell, the potentiostat and the DAQ.
The electrochemical cell
The electrochemical cell consists of three electrodes, the working, counter and reference electrode. The reference electrode keeps the potential between itself and the working electrode constant, and the current is measured between the working and counter electrode.
On the right side is a simplified version of three electrode system. When we apply a potential on the working electrode, redox reactions of analyte will take place at working electrode and counter electrode respectively, thus causing a current to flow in the circuit, which is the current we intend to measure by the ammeter. |
The potentiostatThe potentiostat is a circuit design that applies potential on the electrochemical cell. In a typical experiment, the potential of working electrode is varied linearly from an initial value to a predetermined value when the direction of the scan is reversed. The triangular excitation signal produced by the potentiostat is indicated by the picture on the right.
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DAQThe current produced is converted to data that can be manipulated by a computer through data acquisition unit (DAQ). From the data obtained, a voltammogram is plotted, which is the graph of current produced against potential during the entire potential scan. Based on the voltammogram, redox behaviors of chemical species can be studied.
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