Identification of current nature by elimination voltammetry with linear scan

Abstract

This paper is devoted to the detailed description of mathematical procedures used in the elimination voltammetry with linear scan (EVLS), and their applications to the identification of current nature. It has been shown that the EVLS, based on an elimination function generated from total currents measured at different scan rates, is widely applicable in electrochemistry. The current nature can be identified from the different course of selected elimination functions, i.e., the dependence of the current elimination coefficient β EVLS on the scan rate coefficient x (see Fig. 1). This approach has been tested by studying the reduction processes of azidothymidine (AZT), Pb(II), and Cd(II) on a hanging mercury drop electrode (HMDE). In addition the calculation of elimination function conserving the diffusion current ( I d) and eliminating kinetic and charging currents ( I k, I c) for an adsorbed electroactive substance has been presented. This elimination providing the peak–counterpeak signal which could be observed also at monitoring of Pb(II) reduction on HMDE after adsorption. The fact that EVLS can be generally applied to different ratios of scan rates has been demonstrated for the case of reversible reduction of Cd(II) in KCl solutions. Advantages and disadvantages of EVLS have been discussed.