A new thin film modified glassy carbon electrode based on melaminium chloride pentachlorocuprate(II) for selective determination of nitrate in water

A new electrochemical thin film glassy carbon sensor for nitrate detection based on a copper complex, namely melaminium chloride pentachlorocuprate (H2mela)ClCuCl5 (mela = melamine), as a novel ionophore in plasticized polyvinyl chloride matrix was elaborated. The title complex was synthesized and characterized using FT-IR spectroscopy and single-crystal X-ray diffraction. To improve the sensitivity, the optimal pH value was evaluated and the effect of plasticizer was performed using three different plasticizing solvent mediators: dioctyl sebacate, dibutyl phthalate, and o-nitrophenyl octyl ether. The optimum performance was observed at pH 4 with the membrane incorporating dioctyl sebacate as a plasticizer. Cyclic voltammetry and square wave voltammetry were used to characterize the (H2mela)[CuCl5]Cl-GC sensor with a potential between 0.3 and 1 V. This sensor was characterized by a wide linear range from 1.2 × 10−10 M to 1.2 × 10−7 M, a low limit of detection of 1.2 × 10−10 M and low response time less than 1 min. This proposed sensor gave good results in the determination of nitrate in water and, therefore, can be used successfully in real samples.