铋膜电极方波溶出伏安法测定痕量PbCd

In-situ plating bismuth film on glass carbon electrode for the determination of lead and cadmium by square wave stripping voltammetry

目的考察并优化同位镀铋膜测定Pb、Cd的条件。方法采用方波溶出伏安法,以铋膜电极作为电极测定食品中微量Pb、Cd。结果 Pb、Cd在铋膜电极上可得到灵敏的溶出峰,Pb、Cd的溶出电位分别为0.50 V和0.77 V。当电沉积时间为180 s时,Pb、Cd的检出限分别达1.10μg/L和2.0μg/L,RSD分别为3.5%和2.5%,Pb、Cd在0～100μg/L出现良好的线性关系(r≥0.99)。结论利用本方法测定了样品中Pb的含量,并与石墨炉原子吸收分光光度法做了对比,结果令人满意,同时使用铋膜电极可避免使用汞膜电极带来的环境污染。

Objective The experiment conditions of the determination of lead and cadmium by bismuth film-plated electrode were investigated and optimized.Methods Bismuth film-plated glass-carbon electrode was prepared by in-situ plating for the determination of trace lead in food by square wave stripping voltammentry.Results Sensitive stripping peak of lead and cadmium was obtained at the potential of-0.50V and-0.77V.Following a 180 s preconcentration,the oxidation peak currents changed linearly with the concentration of Pb2＋ and Cd2＋ over the range from 0 μg/L to 100 μg/L（r≥0.99）,and the detection limits of lead and cadmium were 1.1μg/L and 2.0μg/L respectively.RSD were 3.5% and 2.5% respectively.Conclusion The bismuth film-plated electrode was applied to the determination of Pb in preserved egg.Compared with Graphite furnace atomic absorption spectrometry,the concordance of results was satisfactory.