Multivariate curve resolution of polarographic data applied to the study of the copper-binding ability of tannic acid

The interactions between tannic acid (TA) and Cu(II) have been studied by differential pulse polarography (DPP) as a model for the metal ion-tannin interaction in the presence of simultaneously occurring phenomena such as electrodic adsorption, overlapping signals or stabilisation of intermediate Cu(I) species. The high complexity of the system hinders the direct application of the usual strategies of electrochemical hard modelling. As an alternative approach, it is proposed the use of a multivariate curve resolution (MCR) procedure which gives an estimation of the concentration profiles showing the evolution of the complexation-reduction process. Moreover, from such concentration profiles it is possible to estimate the number of Cu(II) ions which can be bound by TA under the conditions of the experiment. (C) 2000 Elsevier Science B.V. All rights reserved.