示波极谱法同时测定尿中铅和镉

Simultaneous Determination of Lead and Cadmium in Urine by Oscilloscopic Polarography

摘要: 研究示波极谱法同时测定尿中铅和镉的方法.运用正交试验选择底液的组成为碘化钾-抗坏血酸-浓盐酸-磷酸.用硝酸、高氯酸、盐酸混合酸消化尿样,消化液在酸性介质中,置极谱仪的三电极系统,样品溶液在滴汞电极上产生还原电流,分别于-480 mV和-620 mV处测量铅和镉的峰电流,对尿样中铅和镉进行测定,铅、镉的质量浓度在100 μg·L-1以内与峰电流呈线性关系.铅、镉的相对标准偏差分别为 6.91%,6.45%,检出限(3S/N)分别为2.0,1.0 μg·L-1,回收率分别为88.4%~101.4%,83.1%~103.5%.

Abstract: An oscilloscopic polarography method for simultaneous determination of Pb(Ⅱ) and Cd(Ⅱ) in urine was studied in this paper.The optimal composition of the supporting electrolytes was selected with orthogonal trial.Under conditions of the optimal composition of supporting electrolytes of potassium iodide-ascorbic acid-hydrochloric acid-phosphoric acid,Pb(Ⅱ) and Cd(Ⅱ) were determined and the linear relationship between peak current and concentration was observed in range of 100 μg·L-1 for both Pb(Ⅱ) and Cd(Ⅱ).RSD′s of the determination were 6.91% for Pb(Ⅱ) and 6.45% for Cd(Ⅱ).DL (3S/N) was 2.0 μg·L-1 for Pb(Ⅱ) and 1.0 μg·L-1 for Cd(Ⅱ).Recovery was in range of 88.4%-101.4% for Pb(Ⅱ) and 83.1%-103.5% for Cd(Ⅱ).