微量地质样品铼锇含量及其同位素组成的高精度测定方法  

High-precision Measurement for the Concentration and Isotopic Composition of Rhenium and Osmium in Micro-amount of Geological Samples

作　　者：储著银[1] 陈福坤[1] 王伟[1] 谢烈文[2] 杨岳衡[2] 

机构地区：[1]中国科学院地质与地球物理研究所固体同位素地球化学实验室,北京100029 [2]中国科学院地质与地球物理研究所MC-ICPMS实验室,北京100029

出　　处：《岩矿测试》2007年第6期431-435,共5页Rock and Mineral Analysis

基　　金：国家自然科学基金项目资助(40525007);科技部国家重点基础研究发展计划项目资助(2006CB403505)

摘　　要：报道了采用新型IsoProbe-T热电离质谱计测定Os含量及其同位素组成和Neptune多接收器等离子体质谱仪(MC-ICPMS)测定Re含量的分析方法。样品化学处理采用Carius管溶样、小型蒸馏法分离和微蒸馏法纯化提取Os以及阴离子树脂交换分离Re的方法。采用IsoProbe-T质谱计测定Os同位素组成具有灵敏度高和精度高的特点。对溶液标样,采用多法拉第接收器系统测定Os总量低至0.2 ng的样品时,平均192Os16O3-离子流强度可达100 mV以上并可维持约20 min,其187Os/188Os同位素比值的测定精度可优于0.1%(1RSD)。采用所建立的化学分离流程和高精度质谱测量方法,测定了铂族元素橄榄岩标样WPR-1中Re、Os含量和Os同位素组成,测定结果与文献报道值在误差范围内吻合。This paper presents the methods for determinations of Os content and measurement of Os isotopic ratios of geological samples by a new thermal ionization mass spectrometer （TIMS, IsoProbe-T） and determination of Re content by Neptune Multi-collector Inductively Coupled Plasma Mass Spectrometer （MC-ICPMS）. Samples were digested using Carius tube method. The Savillex Teflonware distillation and micro-distillation methods were used for Os separation and anion exchange method for Re separation. Measurement of Os isotopic ratios by IsoProbe-T mass spectrometer provides advantages of high sensitivity and high precision. When Os standard solution （containing 0.2 ng Os） is measured, the signal intensity of ^192Os^16O3^- can reach to 100 mV and last for about 20 minutes with precision of better than 0.1% RSD for ^187 Os/^188 Os. By combination of the Re-Os chemical separation procedure presented in this study with high-precision TIMS determination, PGE standard reference peridotite （WPR-1） has been analyzed with satisfactory results.

关 键 词：铼 锇 高精度Os同位素比值测量 负离子热电离质谱法 多接收器等离子体质 谱法(MC—ICPMS) 地质样品 

分 类 号：O611.7[理学—无机化学] O614.713[理学—化学]