THE INFLUENCE OF ELECTROLYTE MEDIA ON THE CATHODIC STRIPPING VOLTAMMETRY OF LEAD DIOXIDE ON GLASSY-CARBON ELECTRODE

The influence of three electrolyte media, namely, acetate buffer, nitric acid, and perchloric acid; on cathodic stripping of lead dioxide at a glassy carbon electrode (GCE) was studied using cyclic voltammetry (CV) and linear sweep stripping voltammetry (LSSV) techniques. One M acetic acid/1 M sodium acetate, 0.1 M nitric acid, and 0.1 M perchloric acid were found to give a sharp cathodic stripping voltammetric (CSV) response. Various factors, such ac concentration of supporting electrolyte, deposition potential (E(dep)), deposition time (t(dep)), and concentration of Pb2+ (C-Pb(2+)), are also presented and discussed. The lowest detection limit of Pb2+ in acetate buffer is 5 x 10(-8) M and, in 0.1 M nitric acid and 0.1 M perchloric acid, is 1 x 10(-5) M. The influence of medium on cathodic stripping peak broadening is analyzed in detail. It is concluded that the formation of insoluble intermediates is the major cause for peak broadening, and the ability of the supporting electrolyte anion to inhibit the formation of such intermediates, through complexation, is the major reason for sharper stripping voltammetry response.