Electroanalytical chemistry of an anticancer drug : 6-mercaptopurine-9-D-riboside

Recently, an analytical method based on catalytic cathodic stripping voltammetry in the presence of nickel ion was proposed [A. Ion, F. G. Banica, C. Luca, Electroanalysis, 1997, 9, 945-949]. This contribution includes the results of the polarographic investigation of the signal-generating process in the above method, namely the catalytic reduction of nickel ion as a complex with MPR. The implication of adsorption processes was evaluated by alternating current polarography and the method of the electrocapillary curves. The occurrence of two different mechanisms for the catalytic nickel reduction was demonstrated: catalysis in the adsorbed state (P1) and catalysis by non-adsorbed MPR molecules (P2). The P1 and P2 components of the overall current result from the deconvolution of the experimental AC polarogram . The consequence of such a mechanism for both kinetic investigations and analytical determination have been be reviewed.