Voltammetry on solid electrode

This article presents the various methods that can be used to improve the performance of solid electrode voltammetric techniques for use in chemical analysis. The improvements that are generally most sought after mainly concern selectivity and lowering the detection limit (to reach the trace analysis range). With regard to selectivity, voltammetric techniques can be improved by deriving voltamograms. This latter approach gave rise to derivative voltammetry, which has seen considerable growth in polarography. As for improving the detection limit, it has been shown that in most cases, lowering it involves either minimizing the residual current by filtering the capacitive current or amplifying the faradic current as a result of the accumulation of electroactive substances near the surface of the indicator electrode. These approaches have given rise to pulse voltammetry and redissolution voltammetry, respectively. After explaining the origin of capacitive current, we show examples of how pulse voltammetry techniques can improve the detection sensitivity of electroactive species. We also show how redissolution voltammetry allows, in particular, the simultaneous detection of four metals, as well as synthetic dyes, with sensitivities compatible with current standards.