VOLTAMMETRIC STUDY OF THE INTERACTION OF CADMIUM WITH BACTERIAL-CELLS

A new method is presented for the interpretation of voltammetric titration curves for systems in which the species have different diffusion coefficients. The change in the metal-to-ligand ratio along the titration curve together with its effect on the coupled diffusion and the overall lability of the system are considered in the interpretation of experimental data. Equations for the evaluation of the free metal concentration remaining in solution are used on each part of the titration curve, according to this parameter. The validity of the method is checked by applying a regression method; the conditional equilibrium constant and complexing capacity can be calculated. The methodology is applied to the case of the titration of living and dead bacterial cells with cadmium ions. Monitoring of cadmium uptake versus time is also performed to show the applicability of voltammetric techniques to the study of the interaction of metals with micro-organisms.