聚苯胺/同位镀铋膜修饰电极脉冲溶出伏安法同时测定铅和镉

Simultaneous determination of lead and cadmium on a polyaniline/bismuth film modified electrode using differential pulse anodic stripping voltammetry

采用电聚合苯胺及同位镀铋膜于玻碳电极表面制备出聚苯胺/铋膜修饰电极,利用所制备的修饰电极以差分脉冲溶出伏安法同时测定溶液中的Pb^(2+),Cd^(2+)。分别采用扫描电镜和红外光谱法表征了修饰电极的形貌与结构特征,并以差分脉冲伏安法对修饰电极的电化学特性进行了研究。实验表明,共沉积形成的铋膜显著增强了待测离子的溶出峰电流。实验优化了缓冲溶液、p H、沉积时间、沉积电位、Bi^(2+)浓度等实验参数。在最佳的实验条件下,溶出峰电流与Pb^(2+),Cd^(2+)分别在0.02~1.0μmol/L和0.04~1.0μmol/L的浓度范围内成良好的线性关系,检出限(S/N=3)分别为5.0 nmol/L和12 nmol/L。方法可用于用于实际水样Pb^(2+),Cd^(2+)的测定。

In this study,a novel polyaniline/bismuth film composite modified glassy carbon electrode（ GCE） was prepared by using electropolymerization of aniline and in situ plating bismuth film methods,successively. This sensor was further used for sensitive determination of trace lead and cadmium ions by differential pulse anodic stripping voltammetry. The morphologies,structure and electrochemistry properties of the modified electrode were characterized by scanning electron microscopy,FT-IR spectroscopy and differential pulse voltammetry. It was found that bismuth film was formed by co-depositionBi^3＋ions and target heavy metals on the surface of electrodes, which significantly enhanced the peak current of target ions. Various experimental parameters such as the buffer solution,p H,deposition time,deposition potential and the concentration of bismuth ions were optimized. Under optimal conditions,the stripping peak currents increase linearly with the increasing concentrations of lead and cadmium ions both in the ranges of 0. 02 ～ 1. 0 μmol/L and 0. 04 ～1. 0 μmol/L with the limits of detection of 5. 0 nmol/L for lead ions and 12 nmol/L for cadmium ions,respectively（ S/N = 3）. The modified electrode has been successfully applied to the determination of trace metal ions in the water samples with satisfactory results.