电感耦合等离子体质谱仪测定可可西里冰芯样品中超痕量Cd和Pb

Directly Determining Cd and Pb in Ice Core of Hoh Xil Regionby Inductively Coupled Plasma Mass Spectrometry

介绍了利用电感耦合等离子体质谱仪 (ICP MS)直接测定冰芯样品中超痕量重金属Cd和Pb的实验和分析方法 ,用国家一级标准溶液进行分析过程中的质量控制 .仪器对测定浓度在 2 0～ 10 0ng·L-1之间Pb的分析精度 <10 % ,对浓度在 5～ 10 0ng·L-1Cd的分析精度 <10 % ,标准加入回收率在85 %～ 10 7%之间 .Cd和Pb的检测下限分别为 0 6 2ng·L-1和 0 15ng·L-1.初步探索了冰芯外部被污染部分的去除方法 ,给出了实验结果 ,并利用此方法对青藏高原马兰冰川的一根 2 2m深冰芯进行了处理 。

A new directly determining Cd and Pb in ice core with ng5L -1 level by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is presented in this paper. The procedures of labware cleaning and the preparing standard solution are described. The blank values are also showed in order to illustrate the reliability of labware cleaning. The determined concentration is in the range of 5 to 200 ng5L -1. Solutions with national standard certificate are used to insure the reliability of the determining. The blank value of Cd is less than 2 ng5L -1 and that of Pb is less than 10 ng5L -1, respectively. For individual determining, the precision for both Cd and Pb is less 10%. The precision among several determined values for a individual concentration value is less 5% for Cd and <10% for Pb, respectively. The recovery determined from standard solutions is in the range of 85%～107%. The limit of detection is 0^15 ng·L -1for Cd and 0^62 ng·L -1 for Pb, respectively, based on ten repeatedly determined blank values. The decontamination method is described, and the concentration of Cd and Pb decreases from the outside to the inner of a core, showing proficiency in the decontamination.;Concentrations of Cd and Pb changing with depth of Malan Ice Core drilled in Hoh Xil of Qinghai Province are also presented. The concentration of Cd is in the range of 0.399～14.735 ng·L -1 with a mean value of 4^6 ng·L -1; the concentration of Pb is in the range of 9～51 ng·L -1 with a mean value of 20 ng·L -1. No obvious change trend of concentrations with depth is found.