Glassy carbon electrodes were modified by films of poly glutamic acid (PAG) obtained after electropolymerization of the glutamic acid in pH 7.0 phosphate buffer solution under successive voltammetric scans from -0.8 V to +2.0 V. The modified electrode were applied for determination of hydrazine, which is pre-concentrated on the electrode surface by interaction of free carboxylic groups bearing in the PAG film and amino group of hydrazine. Although, hydrazine is not electrochemically oxidized on bare electrode, a well defined peak is observed at + 0.57 V with great analytical potentiality. Linear calibration graphs were obtained for hydrazine at concentrations from 4 x 10-5 to 1 x 10-3 mol L-1, using differential pulse voltammetry. Detection limit was calculated and values around 1.2 x 10-6 mol L-1 were obtained. The proposed method was applied to the determination of hydrazine in samples collected from industrial kettle with recovery of around 94 %.
modified electrode; poly glutamic acid film; hydrazine
