VOLTAMMETRIC STUDY OF THE INTERACTION OF CADMIUM WITH BACTERIAL-CELLS

A new method is presented for the interpretation of voltammetric titra tion curves for systems in which the species have different diffusion coefficients. The change in the metal-to-ligand ratio along the titrat ion curve together with its effect on the coupled diffusion and the ov erall lability of the system are considered in the interpretation of e xperimental data. Equations for the evaluation of the free metal conce ntration remaining in solution are used on each part of the titration curve, according to this parameter. The validity of the method is chec ked by applying a regression method; the conditional equilibrium const ant and complexing capacity can be calculated. The methodology is appl ied to the case of the titration of living and dead bacterial cells wi th cadmium ions. Monitoring of cadmium uptake versus time is also perf ormed to show the applicability of voltammetric techniques to the stud y of the interaction of metals with micro-organisms.