用汞膜修饰玻碳电极检测低浓度铀(Ⅵ)

Determination of Trace Uranium(Ⅵ)at the Mercury Film Modified Glassy Carbon Electrode

通过恒电位沉积法将汞修饰在玻碳电极(GCE)上,使形成汞膜修饰玻碳电极(Hg-GCE)。以Hg-GCE为工作电极,在pH=5.7的氯化钾底液中,将U(Ⅵ)与铜铁试剂形成的配合物吸附于电极表面,在0V电位处进行预富集,然后在0^-1.5 V电位范围内进行阴极溶出伏安扫描,U(Ⅵ)被还原产生电流响应。当U(Ⅵ)质量浓度在0~50μg/L及0.1~0.5mg/L范围内,该溶出电流信号与U(Ⅵ)质量浓度呈线性关系。对0.5mg/L U(Ⅵ)进行7次重复测定,测定结果的相对标准偏差为4.1%。于在线仪器上进行干扰试验。50μg/L U(Ⅵ),18.5g/L SO^(2-)_4、1mg/L Fe3+及0.1mg/L Mo^(6+)的干扰可忽略。对矿坑水进行检测,平均回收率为100.4%。

Mercury film was modified on glassy carbon electrode（GCE）by constant potential electrolysis.The mercury film modified glassy carbon electrode（Hg-GCE）is used as working electrode.Uranium（Ⅵ）can form complex with cupferron in KCl electrolyte（pH 5.7）,and the complex is preconcentrated on Hg-GCE at 0V.Stripping voltammogram is recorded from 0to-1.5V and uranium（Ⅵ）is reduced.The produced current signal is proportional to concentration of uranium（Ⅵ）in ranges of 10-50μg/L and 0.1-0.5 mg/L.The RSD of 7determinations for 0.5mg/L uranium（Ⅵ）is 4.1%.For the determination of 50μg/L uranium（Ⅵ）,18.5g/L SO4^2-,1mg/L Fe^3＋or 0.1mg/L Mo^6＋ do not interfere.Average recovery of uranium（Ⅵ）in mine water is 100.4%.