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, I¿ 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.
- fulvic substances
- humic substances