Micellar effects on the reduction of 4-nitroimidazole derivative: Detection and quantification of the nitroradical anion

Abstract

Tne reductive electrochemistry of 1-methyl-4-nitro-2-hydroxymethylimidazole, a 4-nitroimidazole derivative, was examined in the presence of surfactants anionic as sodium dodecyl sulfate (SDS), nonionic, Triton-X, Cationic, Hyamine and Cetyl Trimethyl Ammonium Bromide (CTAB). The reductive mechanism of the nitroimidazole derivative was found to be dependent of both, nature and concentration of the surfactants. By using appropriately the wide versatility of the cyclic voltammetric technique it was possible to study the generation of the nitroradical anion and their stability in different micellar media. The experimental scheme involved the measurement of the current ratio, i(p,a)/i(p.c), from the cyclic voltammograms and its interpolation into theoretical working curves to determine the omega parameter. A plot of omega versus tau resulted in a linear relation described by omega= k(2) C tau where k(2) is the second order rate constant for the decomposition of the nitroradical anion. Cyclic voltammetric experiments demonstrated that the reduction of the 4-nitroimidazole derivative in presence of cationic micelles generated a sufficiently well stabilized nitroradical anion in aqueous medium at pH 7.4. The aim of this study is to investigate the electrochemistry of 4-MNImOH in a micellar medium with the objective to obtain a better approach to the in-vivo conditions and to improve the detection and quantification of the nitroradical anion species.