Hydrazine is a well-known carcinogenic substance with a high reducing property. It is a generalpurpose chemical with wide-range applications in various industries, fuel cells, corrosion inhibiting and etc. The toxic nature of hydrazine as well as its high solubility in water raises the concerns about environmental pollution [1-3]. Therefore, development of simple, fast, accurate and sensitive sensors for monitoring of hydrazine in water, industrial, environmental and biological samples is of crucial importance today. Here, a novel disposable electrochemical sensor for detection of hydrazine is introduced based on gold nanoparticles (AuNPs) covered on a self-assembly monolayer of L-cysteine (SAM) over a gold digital versatile disc (DVD) platform. The characteristics and morphology of AuNPs was characterized by UV-Vis spectroscopy, particle size distribution analysis, atomic force microscopy, and zeta potential analysis. Electrochemical impedance spectroscopy experiments in a ferri/ferrocyanide solution proved that AuNPs really act as an efficient electrocatalyst. Electrochemical behaviour of hydrazine on the AuNPs@SAM@DVD electrochemical sensor was investigated using cyclic voltammetry revealing the efficient electrocatalytic function of the modified electrode. This was confirmed by the decreased oxidation overpotentials and increased peak current response of the hydrazine. The quantitative measurements were carried out by differential pulse voltammetry after thorough optimization of influential operating conditions such as the amount of AuNPs and the pH and the concentration of supporting electrolyte. At last, the analytical performance of the sensor was demonstrated by determination of hydrazine in several environmental samples. The cheap disposable DVD platforms used as a replacement of expensive gold electrodes removes the concerns about the memory effects and tedious solid surface polishing.

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