碳糊电极吸附伏安法测定EMD中的铅

Determine lead in EMD by adsorptive voltammetry at carbon paste electrode

以碳糊电极为工作电极,建立了一种测定电解二氧化锰(EMD)中铅含量的方法。在pH值为3.2的0.1 mol/L邻苯二甲酸氢钾-HCl缓冲溶液中,铅(Ⅱ)与桑色素形成络合物。在0.10 V时富集,铅(Ⅱ)-桑色素络合物吸附于电极表面,在-0.80 V静止还原后进行扫描,在-0.48 V处产生一个灵敏的氧化峰。铅(Ⅱ)浓度在2.0 nmol/L～0.5μmol/L的范围内与二阶导数峰高呈现出良好的线性关系。检测限为1.0 nmol/L(富集时间为200 s)。

A method to determine the lead content in electrolytic manganese dioxide（EMD） was established with carbon paste electrode as working electrode.In 0.1 mol/L potassium hydrogen phthalate-HCl buffer solution with pH value of 3.2,lead（Ⅱ） could form complex with morin.When accumulating at 0.10 V,lead（Ⅱ）-morin complex was adsorbed on the surface of the electrode,a sensitive oxidization peak at-0.48 V was yielded when scanning after still and reduction at-0.80 V.The peak current was proportional to the second-order derivative peak height in the lead（Ⅱ） concentration range of 2.0 nmol/L～0.5 μmol/L,the detection limit was 1.0 nmol/L（accumulation time was 200 s）.