磷酸沉淀分离-电感耦合等离子体质谱法测定化探样品中的痕量银  

Determination of Trace Silver in Geochemical Samples by Inductively Coupled Plasma-Mass Spectrometry with Phosphoric Acid Precipitation Separation

作　　者：刘彤彤 钱银弟 黄登丽 LIU Tong-tong;QIANG Yin-di;HUANG Deng-li(Zhangye Geo-Mine Survey Institute,Non-Ferrous Metal Geological Exploration Bureau of Gansu Province,Zhangye 734000,China;Lanzhou Geo-Mine Survey Institute,Non-Ferrous Metal Geological Exploration Bureau of Gansu Province,Lanzhou 730030,China)

机构地区：[1]甘肃省有色金属地质勘查局张掖矿产勘查院,甘肃张掖734000 [2]甘肃省有色金属地质勘查局兰州矿产勘查院,甘肃兰州730030

出　　处：《岩矿测试》2021年第5期650-658,共9页Rock and Mineral Analysis

基　　金：甘肃省地质勘查基金项目(202004-Y01)。

摘　　要：应用电感耦合等离子体质谱法(ICP-MS)分析化探样品中的痕量银,通常在标准模式下用干扰校正法或动能歧视模式进行测定。银的两个稳定同位素均受锆和铌的氧化物或氢氧化物的质谱干扰,对于干扰元素锆、铌含量较高而银含量低的样品,测定误差较大,需要将干扰元素与银分离。本方法采用硝酸、氢氟酸、高氯酸消解样品,浓盐酸复溶提取,加入磷酸使大部分溶出的干扰元素锆、铌转化为难溶的磷酸盐化合物,通过沉淀与待测元素银分离。ICP-MS测定时以^(103)Rh为内标,用^(90)Zr^(16)O^(+)同质量数的同位素^(106)Pd间接校正^(91)Zr^(16)O^(+)、^(90)Zr^(16)O^(1)H^(+)对107 Ag的质谱干扰。经国家一级标准物质验证,分析结果在标准值的允许误差范围内,相对标准偏(n=12)为4.3%~12.1%,方法检出限(3SD)为0.0072μg/g。本方法适合土壤、水系沉积物及岩石等化探样品中痕量银的分析。样品处理中引入的磷酸不影响其他常规元素,可用同一份消解液进行测定。BACKGROUND:Standard mode with interference correction or kinetic energy discrimination mode is commonly used for the determination of trace silver in geochemical samples by inductively coupled plasma-mass spectrometry(ICP-MS).Interference of both stable isotopes of silver occurs in the mass spectrum of the oxides or hydroxides of zirconium and niobium.Moreover,for samples with a higher content of interfering elements and a lower content of silver,the determination accuracy is low,requiring separation of the interfering element from silver in the solution.OBJECTIVES:To develop a method for the determination of trace Ag in geochemical samples.METHODS:In this method,nitric acid,hydrofluoric acid and perchloric acid were used to digest the sample,which was evaporated to dryness and then redissolved with concentrated hydrochloric acid,with 5mL of 0.05mol/L phosphoric acid added.Most of the dissolved interfering elements of Zr and Nb were transformed into insoluble phosphate compounds,which were separated from the silver by precipitation.^(103)Rh was used as the internal standard to correct the instrument signal drift.The mass spectrum interference of ^(91)Zr^(16)O^(+)and ^(90)Zr^(16)O^(1)H^(+)on 107 Ag was corrected by ^(106)Pd.RESULTS:As proved by first grade standard materials,the result was consistent with standard recommended values,with the relative standard deviation of 4.3%-12.1%(n=12).The detection limit(3SD)of the method was 0.0072μg/g.CONCLUSIONS:This method is suitable for the determination of trace silver in soil,stream sediment and rock samples.The introduction of phosphoric acid does not affect the determination of other conventional elements,and the same digestion solution can be used to determine Ag and other elements.

关 键 词：痕量银 电感耦合等离子体质谱法 化探样品 磷酸盐沉淀 

分 类 号：O657.63[理学—分析化学] O614.122[理学—化学]