Electroanalytical determination of benzidine by differential pulse voltammetry on different electrodes

Benzidine is a solid organic compound which evaporates slowly, especially from water and soil. It was used in the synthesis of azo-dyes widely employed in textile, printing, leather, paper making, drug and food companies around the world. However, in 1973 benzidine was identified as a carcinogenic agent for human urinary bladder because its oxidation by human enzymes can permit its binding with DNA. For these reasons, it belongs to the list of the Priority Pollutants [1-2]. Although benzidine production and use was forbidden in many countries since 1970s, benzidine based azo-dyes are still used in many research laboratories and industries, and its detection and determination is a primarily concern. Various methods for detection of benzidine are proposed in the literature, such as colorimetric, spectroscopic, electrochemical [3] and chromatographic ones. In particular, liquid, high performance liquid and gas chromatography are the most used techniques, frequently associated with mass spectrometry. Electroanalytical techniques and particularly those based on pulsed voltammetry, which are suitable for trace analysis, constitute an interesting alternative in terms of very high sensitivity, low response time, small dimensions and low costs. In this presentation a new method for quantitative detection of benzidine based on differential pulse voltammetry on Glassy Carbon (GC) and Platinum wire bare electrodes is proposed. The use of carbon-based or platinum-based screen printed electrodes (SPE) is also investigated.