高Rb/Sr比值地质样品中Sr同位素的快速分离及高精度测试  

Rapid Separation and Precise Determination of Strontium Isotopic from Geological Samples with High Rubidium/Strontium Ratios

作　　者：刘文刚 李志丹 魏双 陈继[2] 刘郁[2] 奥琮 肖志斌 周红英[1] 刘卉 LIU Wen-Gang;LI Zhi-Dan;WEI Shuang;CHEN Ji;LIU Yu;AO Cong;XIAO Zhi-Bin;ZHOU Hong-Ying;LIU Hui(Tianjin Center, China Geological Survey, Tianjin 300170, China;State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry,Chinese Academy of Sciences, Changchun 130022, China)

机构地区：[1]中国地质调查局天津地质调查中心,天津300170 [2]稀土资源利用国家重点实验室,中国科学院长春应用化学研究所,长春130022

出　　处：《分析化学》2019年第7期1054-1060,共7页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(Nos.41602200,41873066,41502082)资助~~

摘　　要：在高Rb/Sr比值地质样品开展Sr同位素分析测试的过程中,利用传统强阳离子交换树脂进行一次分离纯化很难完全去除^87Rb对于^87Sr同位素测试的同质异位素(同量异位素)干扰。通常选择对样品进行两次分离的方法,该方法虽能确保Sr有好的分离效果,但过程繁琐,较为耗时,不利于批量处理高Rb/Sr比值地质样品的Sr分离。本实验对常规两次分离实验流程进行优化,建立了一种对高Rb/Sr比值地质样品快速分离Sr的实验方法。本方法利用AG50阳离子交换树脂将一次分离富集的Sr溶液直接转入新的阳离子交换树脂柱进行连续分离纯化,可以快速高效完成分离实验。结合高灵敏度热电离质谱仪(TIMS)可实现高Rb/Sr比样品Sr同位素的高精度测试。通过对大量高Rb/Sr比值地质样品的实际验证,此实验流程稳定可靠,具有重要的应用价值。When strontium (Sr) isotopic analysis is carried out for geological samples of high rubidium (Rb)/Sr ratios, it is difficult to completely remove the isobaric interference of Rb on Sr isotopic analysis by using traditional strong acid cation exchange resin for a single separation and purification. Actually, one purification procedure performed twice is necessary to eliminate the interference of ^87Rb on the testing of ^87Sr/^86Sr. Although the purification procedure could ensure a good effect on the separation and purification of Sr, the process is tedious and time-consuming, which is not suitable for simultaneous separation and purification of Sr from large quantity of geological samples with high Rb/Sr ratios. In this study, the conventional twice separation process was optimized, and an experimental method for rapid separation of Sr from geological samples with high Rb/Sr ratios was established. The Sr solution after purified by AG50 resin was added to a new AG50 resin directly to purify Rb and Sr again. The whole separation process would be accomplished quickly and efficiently. The method combined with high sensitive thermal ionization mass spectrometry (TIMS) is completely satisfied to high precision determination of ^87Sr/^86Sr isotope ratios for the samples of high Rb/Sr ratios. Through the application of the new separation method with a large number of geological samples of high Rb/Sr ratios, it is proved that the experimental process is stable and reliable and showing crucial application value.

关 键 词：地质样品 高Rb/Sr比 连续分离 阳离子交换树脂 ^87Sr/^86Sr比值 

分 类 号：O657.63[理学—分析化学] P623[理学—化学]