钾同位素的高效分离及MC-ICP-MS高精确测定  

High-efficient purification and accurate determination of K isotope using MC-ICP-MS

作　　者：程原原 李国鼐 李杨子 邓丽[1] 贺茂勇[1,4] 刘陆柏洋 罗家馨 金章东 CHENG Yuan-yuan;LI Guo-nai;LI Yang-zi;DENG Li;HE Mao-yong;LIU Lu-bai-yang;LUO Jia-xin;JIN Zhang-dong(State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi′an 710061,China;Chinese Flight Test Establishment,Xi′an 710089,China;University of Chinese Academy of Sciences,Beijing 100049,China;Qinghai Normal University,Academy of Plateau Science and Sustainability,Xining 810016,China;Xi′an Institute for Innovative Earth Environment Research,Xi′an 710061,China)

机构地区：[1]中国科学院地球环境研究所,黄土与第四纪地质国家重点实验室,西安710061 [2]中国飞行试验研究院,西安710089 [3]中国科学院大学,北京100049 [4]青海师范大学,高原科学与可持续发展研究院,西宁810016 [5]西安地球环境创新研究院,西安710061

出　　处：《矿物岩石地球化学通报》2023年第2期369-379,共11页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：中国科学院战略性先导科技专项B课题(XDB40000000);中国科学院仪器设备功能开发技术创新项目(2023g106);国家自然科学基金资助项目(41991252,42173023);陕西省杰出青年科学基金资助项目(2022JC)。

摘　　要：钾(K)在地球科学、生物科学、环境科学等领域有广泛应用。为了高效地从地质、生物、环境等样品中分离纯化K并进行其同位素测定,经反复实验和优化,建立了适用于不同样品中K同位素的高效分离和多接收电感耦合等离子体质谱测定方法。选取AG 50W-X8树脂(200~400目),以0.5 mol/L HNO_(3)为淋洗液,过柱一次,即可实现K的完全纯化分离,其回收率均大于99.9%,空白(约10 ng)。对于基体元素(Li、Na、Mg、Al、V、Cr、Ca等)含量较高的样品,建议二次过柱分离纯化。分离纯化的样品在MC-ICP-MS上采用“冷等离子体+低分辨”方法进行测定。标准物质(岩石标样、煤标样和生物质标样)的测试结果与前人分析结果一致,δ^(41)K值的长期精度均好于0.06‰,且重现性较高。Potassium(K)is widely applied in earth sciences,biological sciences,environmental sciences and other fields.This study presents a method for high-efficient purification for a variety of samples and high-precision determination for K isotopes by multi-collector inductively coupled plasma mass spectrometry(MC-ICP-MS).Potassium in digested samples was separated by cation-exchange chromatography with AG 50W-X8 resin,and was eluted by 0.5 mol/L HNO_(3).It’s achieved a high recovery of K with the yield of>99.9%and negligible blank(~10 ng K).Nevertheless,for samples with high contents of matrix elements(Li、Na、Mg、Al、V、Cr、Ca),two-step purification procedure is suggested.The purified samples were analysed by MC-ICP-MS using"cold plasma-low resolution".The values of δ^(41) K of international standards(rock、coal and biology)are consistent with literature,and the long-term precision is better than 0.06‰with good reproducibility.

关 键 词：K分离纯化 K同位素 MC-ICP-MS 测定 

分 类 号：P595[天文地球—地球化学]