Adsorptive accumulation in constant current stripping chronopotentiometry as an alternative for the electrochemical study of metal complexation by thiol-containing peptides

Constant current chronopotentiometric stripping analysis using adsorptive accumulation and negative current (AdSCP) was applied as an alternative for the study of metal complexation of glutathione (GSH) or (γ-Glu-Cys)2-Gly (PC2) with zinc ions on hanging mercury drop electrode. The behavior of the formed Zn-complexes was studied using voltammetric and chronopotentiometric methods. A multivariate curve resolution method by alternating least-squares (MCR-ALS) applied to DP voltammetric and chronopotentiometric measurements of Zn–PC2 system made possible the formulation of a complexation model. Moreover, the use of small currents in AdSCP allows one to obtain acceptable sensitivities and signal separation at very low concentrations, which is important in peptide studies under conditions similar to these of natural media.