Electrooxidation of hydrazine by carminic acid as a mediator on a glassy carbon electrode

Electrocatalytic oxidation of hydrazine on a glassy carbon electrode with carminic acid as a homogeneous mediator in 0.1 M phosphate buffer solution (pH 8.0) was studied. Cyclic voltammetry study showed that the catalytic current of the system depends on the concentration of hydrazine. The magnitude of the peak current obtained by linear sweep voltammetry for carminic acid increased sharply in the presence of hydrazine and proportional to the hydrazine concentration in the ranges of 5.0-800.0 μM and the detection limit was 3.0 μM by this technique. The detection limit was promoted by differential pulse voltammetry and decreased to 0.03 μM. The diffusion coefficient of hydrazine was estimated using chronoamperometry. The chronoamperometry studies were also used to determine the rate constant for catalytic reaction of carminic acid with hydrazine. The experimental results showed that the peak current varied in the presence of different bivalence and more, metal cations, but these interferences were omitted in the alkaline media and in the presence of EDTA, while almost all anions and univalence metal cations had no effect on the peak current of hydrazine. The proposed method was used for analysis of hydrazine in real samples.