电化学还原石墨烯修饰玻碳电极测定痕量银

在玻碳电极表面,用电化学还原氧化石墨烯,制备了石墨烯修饰玻碳电极。通过优化支持电解质及其pH值、修饰剂用量、富集电位及时间等测定条件,建立了基于该电极测定痕量银的线性扫描阳极溶出伏安分析法。含痕量银溶液在pH 4.0的NaAc-HAc缓冲液中,-0.10 V电位下富集5 min后,于0.32 V处出现一灵敏度高、峰形较好的银阳极溶出峰,溶出峰电流与Ag⁺浓度在1.0×10^-7 ~ 4.0×10^-5 mol/L范围内线性关系良好,检出限为3.0×10^-8 mol/L(S/N=3)。方法用于环境水样中痕量银的测定,平均回收率在95%~107%之间。

Determination of trace silver with electrochemically reduced-graphene modified glassy carbon electrode

A graphene-modified electrode was prepared with graphene oxide (GO) reduced by electrochemistry on the surface of a glassy carbon electrode (GCE). A linear sweep stripping voltammetry for the determination of trace silver was developed by optimizing the determination conditions such as supporting electrolyte and pH, the amount of modifier, and the accumulation potential and time. In NaAc-HAc buffer solution at pH 4.0, an anodic stripping peak with high sensitivity and good shape appeared at 0.32 V after the soluion containing trace silver was accumulated at -0.10 V for 5 min. The stripping peak current showed a linear relationship with the concentration of Ag⁺ in the range of 1.0×10^-7-4.0×10^-5 mol/L with a detection limit of 3.0×10^-8 mol/L (S/N=3). The proposed method has been applied to the determination of silver in environmental water samples with satisfactory results, and the average recoveries were between 95% and 107%.