同位镀锑膜修饰电极方波溶出伏安法同时测定痕量锡、镉

In-situ plating antimony film electrode for simultaneous determination of tin and cadmium by square wave stripping voltammetry

目的:建立同位镀锑膜电极测定痕量锡和镉的新方法。方法:在玻碳电极上,采用同位镀锑的方法富集被测离子并形成锑膜,利用方波脉冲伏安法使富集的Sn、Cd重新溶出,根据溶出峰电流,实现对痕量Sn2+、Cd2+的同时测定。在十六烷基三甲基溴化胺(CTAB)存在的条件下,溶出峰形良好。讨论了底液的pH值、CTAB浓度、富集时间、富集电位和不同的扫描速率对金属离子溶出峰的影响。结果:在优化实验条件下,Sn2+和Cd2+的线性范围分别为5μg/L～180μg/L和10μg/L～170μg/L,最低检出限分别为0.46μg/L和2μg/L。利用本方法测定了茶叶中Sn2+的含量,结果令人满意。结论:锑膜电极可成为又一种新的环保型膜电极用于重金属离子的测定。

Objective： To establish a method for simultaneous determination of Sn2＋ and Cd2＋ with an unique film electrode.Methods： The analytes were accumulated by in-situ plating antimony film on carbon electrodes and simultaneous determination of Sn2＋ and Cd2＋ with the antimony film electrodes by square wave stripping voltammetry was conducted in the presence of cetyltrimethylammonium bromide（CTAB）.The experimental parameters,such as the composition and concentration of supporting electrolyte,CTAB concentration,scanning rate,accumulation potential and deposition time were optimized to achieve the best sensitivity and selectivity.Results： Under optimized conditions,the peak current was linearly correlative with the concentration of Sn2＋ and Cd2＋ in the range of 5 μg/L^180 μg/L and 10 μg/L^170 μg/L respectively,with all the correlation coefficients≥0.99.The detection limits of the method were 0.46 μg/L and 2 μg/L for Sn2＋ and Cd2＋,respectively.The proposed method was successfully applied to determine Sn2＋ in tea sample.Conclusion： Antimony film electrode could be another new environment-friendly membrance electrode for determination of heavy metal ions.