SQUARE-WAVE ANODIC STRIPPING VOLTAMMETRY (SWASV) FOR THE DETERMINATION OF ECOTOXIC METALS, USING A BISMUTH-FILM ELECTRODE

This article reviews the use of square wave anodic stripping voltammetry for the simultaneous determination of ecotoxic metals (Pb, Cd, Cu, and Zn) on a bismuth-film (BiFE) electrode. The BiFE was prepared in situ on a glassy-carbon electrode (GCE) from the 0.1 mol L-1 acetate buffer solution (pH 4.5) containing 200 mu g L-1 of bismuth (III). The addition of hydrogen peroxide to the electroanalytical cell proved beneficial for the interference-free determination of Cu (II) together with zinc, lead, and cadmium, using the BiFE. The experimental variables were investigated and optimized with the view to apply this type of voltammetric sensor to real samples containing traces of these metals. The performance characteristics, such as reproducibility, decision limit (CC alpha), detection capability (CC beta), sensitivity, and accuracy indicated that the method holds promise for trace Cu2+, Pb2+, Cd2+, and Zn2+ levels by employment of Hg-free GCE with SWASV. CC alpha, and CC beta were calculated according to the Commission Decision of 12 August 2002 (2002/657/EC). Linearity was observed in the range 20-280 mu g L-1 for zinc, 10-100 mu g L-1 for lead, 10-80 mu g L-1 for copper, and 5-50 mu g L-1 for cadmium. Using the optimized conditions, the stripping performance of the BiFE was characterized by low limits of detection (LOD). Finally, the method was successfully applied in real as well as in certified reference water samples.