Determination of Trace Amount of Unsym-Dimethylhydrazine in Water by Cyclic Voltammetry with MWNTs Modified Glassy Carbon Electrode

Multi-walled carbon nanotubes modified glassy carbon electrode was prepared by dropping method. Cyclic voltammetry was applied to the determination of trace amount of unsym-dimethylhydrazine in water. It was found that multi-walled carbon nanotubes modified glassy carbon electrode had good enrichment and electrocatalytic activity for unsym-dimethylhydrazine. The optimized conditions found were as follows:① supporting electrolyte was PBS of pH 7.0; ② enrichment potential was 0.8 V; ③ enrichment time was 120 s. Linear relationship between values of oxidation peak current and concentration of unsym-dimethylhydrazine was kept in the range of 6.6×10^-6-1.45×10^-4mol·L^-1, with detection limit (3S/N) of 7.3×10^-7mol·L^-1. Precision of the method was tested at the concentration level of 5.0×10^-5mol·L^-1 unsym-dimethylhydrazine standard solution for 5 determinations, and value of RSD found was 1.5%. The proposed method was applied to the analysis of simulated water sample, giving values of recovery in the range of 99.3%-112%.