王水提取-电感耦合等离子体质谱法同时测定地质样品中微量银、镉、铋

Determination of silver, cadmium and bismuth in geological samples by inductively coupled plasma mass spectrometry with aqua regia treatment

样品用水浴加热、王水提取预处理,采用电感耦合等离子体质谱法同时测定了土壤、水系沉积物及岩石等地质样品中的痕量Ag、Cd和Bi.在样品预处理阶段,主要干扰元素Zr和Nb只有少量被溶出,而分析元素Ag、Cd和Bi的溶出趋于完全,这样在样品预处理阶段就完成了分析元素与干扰元素的有效分离, 减小了多原子离子93Nb16O+, 92Zr16OH+, 92Mo16OH+对109Ag的干扰和95Mo16O+, 94Zr16OH+, 94Mo16OH+对111Cd的干扰.方法对实际样品的检出限(10σ,DF=300)Ag,Cd和Bi的质量分数分别为5.1, 4.3和10.5 ng/g.对不同含量样品7次测定的RSD为8.7%～1.8%.用该方法对土壤、水系沉积物及岩石等国家一级标准物质进行分析,分析数据均在标准推荐值的允许误差范围内.

A method for simultaneous determination of trace sliver, cadmium and bismuth in geological samples by inductively coupled plasma mass spectrometry was developed. The experiments showed that almost all of analyre elements （Ag, Cd, Bi） and only a few of the interfeting elements （Zr, Nb, Mo） were dissolved using aqua regia in a boiling water bath, and the analyte elements were separated from the interfering elements in sample digestion process and the potential interference of polyatomic ions ^93 Nb^16O^＋ , ^92 Zr^16 OH^ ＋ , ^92 Mo^16 OH^ ＋ , ^93 Mo^16O^＋ , ^94Zr^16OH^＋ and ^94Mo^16OH^＋ in ^109Ag^＋ and ^111 Cd^＋ determination were decreased. The method detection limits （10σ, DF= 300） were 5.1, 4.3 and 10.5 ng/g （dry mass） for sliver, cadmium and bismuth, respectively. Precision （ n = 7） was between 1. 8 and 8.7 % RSD. The method was applied to the determination of trace Ag, Cd and Bi in a series of Chinese geological reference materials （soils, stream sediments and rocks）, and the results were found to be in reasonable agreement with the certified values.