Multivariate curve resolution of cyclic voltammetric data:: Application to the study of the cadmium-binding properties of glutathione

Multivariate curve resolution is applied to cyclic voltammetry (CV) data obtained in the study of Cd(II) complexation by glutathione (GSH), The relatively poor resolution of CV hinders the direct interpretation of raw data. The use of CV is improved by the combination of several chemometric techniques based on factor analysis: singular-value decomposition, evolving factor analysis, and multivariate curve resolution with constrained alternating least squares optimization including a new peak-shape constraint. This multivariate analysis data treatment simultaneously reveals the formation of Cd(GSH)(2) and Cd-2(GSH)(2) complexes, through the calculated concentration profiles, and allows the assignment of numerically obtained pure individual CV signals for the different Cd(IS) ions present in solution (free and bound) and involved in the electrochemical process.