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

摘要

Electrocatalytic oxidation of hydrazine on a glassy carbonelectrode with carminic acid as a homogeneous mediator in 0.1 Mphosphate buffer solution (pH 8.0) was studied. Cyclic voltammetrystudy showed that the catalytic current of the system depends on theconcentration of hydrazine. The magnitude of the peak currentobtained by linear sweep voltammetry for carminic acid increasedsharply in the presence of hydrazine and proportional to the hydrazineconcentration in the ranges of 5.0-800.0 mu M and the detection limitwas 3.0 mu M by this technique. The detection limit was promoted bydifferential pulse voltammetry and decreased to 0.03 mu M.The diffusion coefficient of hydrazine was estimated usingchronoamperometry. The chronoamperometry studies were also used todetermine the rate constant for catalytic reaction of carminic acidwith hydrazine. The experimental results showed that the peak currentvaried in the presence of different bivalence and more, metal cations,but these interferences were omitted in the alkaline media and in thepresence of EDTA, while almost all anions and univalence metal cationshad no effect on the peak current of hydrazine. The proposed methodwas used for analysis of hydrazine in real samples.