Voltammetry in which a square-wave potential waveform is superimposed on an underlying linearlyhyphen‐varying potential ramp or staircase ramp. The current is sampled just before the end of the forward-going pulse and of the backward-going pulse and the difference of the two sampled currents is plotted versus the applied potential of the potential or staircase ramp. The square-wave voltammogram is peak-shaped. See figure.
- The sensitivity of SWV depends on the reversibility of the electrode reaction of the analyte.
- Most instruments show plots of the current at the end of the forward-going pulse and of the backward-going pulse vs. the potential, as well as their difference. This can give valuable information on the kinetics of the electrode reaction and the electrode process.
(a) Waveform for square wave voltammetry (not to scale). Typical values for pulse parameters are \(\tau = \pu{10 ms}\), \(t_{\rm{p}} = \pu{5 ms}\), \(E_{\rm{\tau}} = \pu{25 mV}\), \(E_{\rm{step}} = \pu{4 mV}\). Sampling interval indicated by horizontal curly brackets is typically \(\pu{1 ms}\). (b) Square wave voltammogram of the difference between currents sampled at ‘2’ and ‘1’ against applied potential.
PAC, 2020, 92, 641. 'Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)' on page 678 (https://doi.org/10.1515/pac-2018-0109)