Electrochemical oxidation of isoniazid catalyzed by (FcM)TMA at the platinum electrode and its practical analytical application

The electrocatalytic oxidation of isoniazid (INH) by (ferrocenylmethyl) trimethylammonium [(FcM) TMA] at the platinum electrode in 0.10 M Na2SO4 aqueous solution was studied by cyclic voltammetry (CV). Although INH itself showed a very poor electrochemical response at the platinum electrode, the response could be greatly enhanced by using (FcM) TMA as a mediator, which enables a sensitive electrochemical determination of the substrate INH. The reaction rate constant for catalytic oxidation reaction was evaluated as (3.98 +/- 0.10) x 10(3) M-1 s(-1) by using chronoamperometry (CA). Experimental conditions such as supporting electrolyte and its concentration, solution pH, and the concentrations of the catalyst (FcM) TMA and the substrate INH were investigated to maximize the current efficiency of the electrocatalytic oxidation. The method can be used for the sensitive practical determination of INH, and also opens an avenue for using (FcM) TMA as a mediator in electroanalytical determination which is very simple, cheap, and rapid. Furthermore, no sample pretreatment or time- consuming extraction steps are required prior to the analysis.