多壁碳纳米管修饰玻碳电极的循环伏安法测定水中微量偏二甲肼

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

采用滴涂法制备多壁碳纳米管修饰玻碳电极,用循环伏安法测定水中微量偏二甲肼。多壁碳纳米管修饰玻碳电极对偏二甲肼有良好的富集特性和电催化活性。优化的试验条件如下:(1)支持电解质为pH 7.0的磷酸盐缓冲溶液;(2)富集电位为0.8V;(3)富集时间为120s。偏二甲肼的浓度在6.6×10^(-6)~1.45×10^(-4) mol·L^(-1)内与其对应的氧化峰电流呈线性关系,方法的检出限(3S/N)为7.3×10^(-7) mol·L^(-1)。对5.0×10^(-5) mol·L^(-1)偏二甲肼标准溶液连续测定5次,测定值的相对标准偏差为1.5%。方法用于模拟水样的分析,加标回收率为99.3%~112%。

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× 10-7 mol · L-1. Precision of the method was tested at the concentration level of 5. 0× 10- 5 mol · 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%.