Adsorptive square-wave voltammetry of quasi-reversible electrode processes with a coupled catalytic chemical reaction

Abstract

There are several strategies for enhancing the sensitivity of electroanalytical methods. Usually, those strategies are based on the selection of the voltammetric technique, the inclusion of an accumulation step, and the eventual addition of a catalytic chemical reaction that regenerates the electroactive species. Square-wave voltammetry (SWV) is one of the most sensitive techniques. In the case of electroanalytical applications, it is typically preceded by an electrochemical or adsorptive pre-concentration step. In this manuscript, the theory of SWV for a quasi-reversible electrode process coupled to a catalytic chemical reaction between an adsorbed reagent and a soluble product is presented. The dependences of the dimensionless net peak current and its peak potential on the value of the standard charge transfer rate constant are described. The variation of the SWV parameters such as frequency and potential pulse amplitude are discussed. The effect of the chemical and electrochemical kinetics on the voltammetric profile is analyzed.