The effect of acetate concentration, solution pH and conductivity on the anodic stripping voltammetry of lead and cadmium ions at in situ bismuth-plated carbon microelectrodes

The use of carbon microdisc electrode substrates allowed Pb(II) and Cd(II) anodic stripping voltammetry at in situ plated bismuth films to be studied in an extended acetate buffer/electrolyte concentration range that includes very low or zero acetate levels. The change of the Pb and Cd Square Wave Anodic Stripping Voltammetry (SWASV) peak height with acetate concentration, pH and conductivity has been studied systematically. It was found that the stripping peak signal is considerably enhanced in the absence of added acetate or in acidic solutions. This behaviour has been attributed to the extent of metal ion complexation at different levels of free acetate ions that are present at different buffer concentrations or pH values. Recording both the forward and the reverse voltammograms of each SWASV curve, the signal variation could be attributed to changes in the metal ion deposition rate (as its complexation state is varied) both during the preconcentration step and the reverse pulse of the SWASV potential sequence.