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, E-p, and peak half-width, w(1/2)) for determination of metal ion speciation. This study focuses on depletive SCP (low stripping current, Itau constant), and considers the change in E-p and w(1/2) 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 E-p and w(1/2) 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. (C) 2002 Elsevier Science B.V. All rights reserved.