A chronoamperometric study of the oxidative nucleation of niazid and isoniazid on mercury electrodes in basic solutions

Using chronoamperometric measurements at pH 12 it is shown that the oxidation mechanism of niazid adsorbed on the mercury electrode changes with respect to the mechanism reported in the literature for the electrooxidation of the molecules reaching the electrode by diffusion. A compact monolayer of niazid molecules is formed on the electrode surface, being the hydrazide oxidized through a two-electron process. The oxidation product is not able to dissociate a H + ion, and the oxidation process does not proceeds beyond. For isoniazid the monolayer never becomes compact.