Differential pulse polarographic study of the Pb(II) complexation by glutathione

Differential pulse polarography (DPP) is applied to the study of the complexes of Pb(II) with glutathione (GSH). As occurred in previous studies on Cd(II)– and Zn(II)–GSH complexes, the system presented overlapping of the peaks of free metal and metal complexes but, additionally, the interference of the anodic signals of mercury in the presence of GSH. This necessitated, even more than in previous work, the use of a multivariate curve resolution method (MCR-ALS) to extract quantitative information from the system. Despite the important interference of anodic signals, the combined use of DPP and MCR-ALS suggested the presence of two kinds of Pb(II)–GSH bonds and allowed the prediction of stoichiometries for the complexes formed.