Stripping chronopotentiometry at scanned deposition potential (SSCP). Part 1. Fundamental features

A rigorous theory for the shape and characteristics of (deposition potential) scanned stripping chronopotentiometry (SSCP) curves is presented. Their fundamental features are investigated and compared with those of dc polarograms. An equation is derived that fully describes the relationship between stripping time, tau, and deposition potential, E-d, in the complete depletion regime at both a conventional HMDE and a microelectrode. This equation is explicit in the analytical signal, tau, and shows that for a reversible system the tau, E-d waveform is basically different from the conventional polarogram. Specifically, it is distinctly steeper and does not conform to a linear log-plot. Still, the shift in half-wave potential in the presence of complexing agents, as well as the effect of a reduced diffusion coefficient for the metal complex species, can be interpreted straightforwardly, analogous to the DeFord-Hume expression for a polarographic wave. (C) 2002 Elsevier Science B.V. All rights reserved.