预镀汞膜玻碳电极差分脉冲伏安法测定铜精矿中痕量铅

Pre-coated mercury film on glassy carbon electrode for the determination of trace lead in copper concentrate stone by differential pulse stripping voltammetry

通过构建预镀汞膜修饰玻碳电极,利用差分脉冲溶出伏安法对铜精矿石中的痕量铅进行测定并得到良好的结果.讨论了不同镀汞液浓度对电极性能的影响;底液的pH值、沉积时间、沉积电位对Pb测定的影响.实验结果表明,通过施加电极活化使得工作电极表面状态稳定,重现性好.在选择的最优条件下对1～15μg/L、5～60μg/L、40～650μg/L、500～1 000μg/L 4个不同的标准浓度系列的Pb2+测定,Pb的溶出峰电流与Pb2+浓度呈现良好的线性关系(r≥0.999),Pb2+浓度的线性范围为5～1 000μg/L;沉积时间180 s下,Pb的检出限0.16μg/L.利用本方法测定了铜精矿中Pb的含量,并与火焰原子吸收光谱法做了比较,得到结果基本一致.

The pre-coated mercury film adopted as a modifier at the glassy carbon electrode is used to measure the trace lead of the stone copper concentrate with differential pulse stripping voltammetry.Good results was achieved.The several important operational parameters such as the concentration of Hg2＋,pH of supporting electrolyte,de-position time and potential were investigated.Experimental results show that the surface status of working electrode is stable with good reproducibility.Following the best condition,the concentration series ranged from 1~15 μg/L,5~60 μg/L,40~650 μg/L,500~1 000 μg/L for the simultaneons determination of Pb ions was examined.results show the correlation coefficients is very good（r≥0.999）,The oxidation peak currents change linearly with the concentration of Pb2＋in the range of 5~1 000 μg/L,and the detection limit is 0.16 μg/L when the deposition time is 180 s.Comparing the result with that of flame atomic absorption spectrometry（FAAS）,the concordance of results was satisfactory.