噻二唑类导电聚合物膜修饰玻碳电极对镉的测定

Determination of Cd(Ⅱ) by Using an Electrode Modified with Electropolymerized Thiadiazole Film

以2,5-二巯基-1,3,4-噻二唑(DMTD)为导电聚合物,利用循环伏安法制备导电聚合物膜修饰玻碳电极。并以此为工作电极,建立了以阳极溶出伏安法测定痕量镉的电化学分析法。优化了检测镉的条件,最后确定在0.1mol.L-1 pH 5.5的NaAc/HAc缓冲溶液中,电压-1.2V富集300s为最佳条件。Cd2+的浓度与溶出峰电流在0.5～100μg.L-1的范围内呈良好的线性关系,检测限为5.0×10-8g.L-1。实验结果表明,玻碳电极经DMTD导电聚合物膜修饰后检测灵敏度显著地提高。该法已用于实际水样中痕量镉的测定,回收率在97.4%～102%之间。

The present study reports a glassy carbon electrode was modified with electropolymerized film of 2,5-dimercapto-1,3,4-thiadiazole（DMTD） by cyclic voltammetry.An electrochemical analysis method for the simultaneous determination of trace lead and cadmium by differential pulse stripping voltammetry was developed using this electrode as working electrode.In 0.1 mol·L-1 NaAc2/HAc buffer solution at pH 5.5,the stripping peak current after enrichment at-1.2 V for 300 s showed a good linear relationship with Cd2＋ in the range of 0.5—100 μg·L-1.The detection limits was 5.0×10-8g·L-1.The results indicated that the detection sensitivity of glassy carbon electrode modified by electropolymerized film of DMTD was significantly improved.The proposed method has been applied to the determination of trace lead and cadmium in actual water samples with the recovery rate of 97.4%～102%.