Significance of wave form parameters in stripping chronopotentiometric metal speciation analysis

An analysis is presented of the significance of stripping chronopotentiometric (SCP) stripping peak parameters (peak potential, Ep, and peak half-width, w1/2) for determination of metal ion speciation. This study focuses on depletive SCP (low stripping current, Iτ constant), and considers the change in Ep and w1/2 in the presence of complexing and/or adsorbing ligands at both a conventional mercury drop electrode (HMDE) and a micro mercury droplet. We show that at a microelectrode, or at sufficiently long deposition time at a HMDE, the changes in Ep and w1/2 can be related to metal speciation in the bulk solution. Unlike transient stripping voltammetric methods such as DP-SV, depletive SCP is applicable even in the presence of adsorption of ligand and induced metal ion adsorption.