酸溶分解-电感耦合等离子体质谱内标法测定地质样品中的痕量银  

Determination of Trace Silver in Geological Samples by Inductively Coupled Plasma-Mass Spectrometry with Acid Decomposition and Internal Standard Calibration

作　　者：刘海明 武明丽 成景特 LIU Hai-ming;WU Ming-li;CHENG Jing-te(Key Laboratory of Radioactive and Rare Scattered Mineral,Ministry of Natural Resources,Shaoguan 512026,China;Guangdong Key Laboratory of Radioactive and Rare Resource Utilization,Shaoguan 512026,China)

机构地区：[1]自然资源部放射性与稀有稀散矿产重点实验室,广东韶关512026 [2]广东省放射性与三稀资源利用重点实验室,广东韶关512026

出　　处：《岩矿测试》2021年第3期444-450,共7页Rock and Mineral Analysis

基　　金：广东省省级科技计划项目(2018B030322009)。

摘　　要：应用电感耦合等离子体质谱法(ICP-MS)测定地质样品中的痕量银时,Zr、Nb、Mo的氧化物以及氢氧化物对银的两个质量数^(107)Ag和109 Ag造成严重的质谱重叠干扰,导致结果有明显的偏差。针对此问题,本文基于^(107)Ag的质谱干扰相对单一,只有^(90)Zr^(16) OH^(+)和^(91)Zr^(16) O^(+)对^(107) Ag产生干扰,在ICP-MS分析中选用^(107)Ag对银进行测定。样品前处理中采用氢氟酸、高氯酸、硝酸敞开消解,在浸提液中加入过量氨水,将^(107)Ag的主要干扰元素Zr通过生成沉淀实现分离,以Re作内标补偿基体效应和信号漂移,采用ICP-MS测定了水系沉积物、岩石、土壤国家标准物质中痕量银的含量,测试值与认定值一致,方法检出限为0.0031μg/g,相对标准偏差(RSD)为4.38%。该方法简捷,在浸取液中加入氨水之前可以先测定常见金属元素,实现了浸取溶液的循环再利用。BACKGROUND:Inductively coupled plasma-mass spectrometry(ICP-MS)is used for the determination of trace silver in geological samples.Hydroxides and oxides of Zr,Nb,Mo cause serious overlapping interference on the two mass numbers of ^(107)Ag and 109 Ag,which can result in a significant deviation of the results.OBJECTIVES:To develop a method for precise determination of trace Ag in geological samples.METHODS:Considering that the MS interference of ^(107)Ag is relatively simple and only ^(90)Zr^(16) OH^(+) and ^(91)Zr^(16) O^(+) have interferences on ^(107)Ag,^(107)Ag was selected for the determination of silver in ICP-MS analysis.In the sample pretreatment,hydrofluoric acid,perchloric acid and nitric acid were used for open digestion,and excessive ammonia was added to the extraction solution.The main interference element Zr of ^(107)Ag was separated by precipitation.Trace silver was determined with Re as the internal standard to complement matrix effect and signal drift.RESULTS:The content of trace silver in national standard materials of stream sediment,rock and soil was determined by ICP-MS.The test value was consistent with the certified value.The detection limit of the method was 0.0031μg/g,and the relative standard deviation(RSD)was 4.38%.CONCLUSIONS:The method has the advantages of simple and accurate measurement of trace silver.Moreover,common metal elements can be determined before adding ammonia to the leaching solution,so that the extraction solution can be recycled.

关 键 词：地质样品 痕量银 酸溶 氨水 内标法 电感耦合等离子体质谱法 

分 类 号：O657.63[理学—分析化学] TQ174.73[理学—化学]