高精度稳定锶同位素分析方法综述

近年来稳定Sr同位素在同位素地球化学领域越来越受到重视，在表生地球化学、古环境、考古学、地球内生作用及陨石等方面研究都取得了重要成果，这得益于高精度稳定Sr同位素分析方法的发展。文章总结了δ88/86Sr分析方法的关键技术要素。在化学提纯方面，文献中广泛使用Sr特效树脂，用离子交换法实现Sr元素的分离提纯，但Sr特效树脂价格昂贵，且具有难以消除的记忆效应，建议用阳离子树脂代替；在质谱分析方面，主要使用多接收电感耦合等离子体质谱（MCICP-MS）和热电离质谱（TIMS）进行测量，MC-ICP-MS测量具有比TIMS更高的测量效率，但是测量精度略低；对于质量歧视校正，目前使用较为广泛的方法有标样—样品间插法、Zr元素外部校正法以及双稀释剂法，其中双稀释剂法具有较高的测量精度，但在MC-ICP-MS上应用的相关研究较少。目前还缺乏对国际标准样品的δ88/86Sr的详细对比。因此，优化分析流程、提高测量精度以及更多标准样品δ88/86Sr的测定是需要加强的工作。

High Precision Analytical Method for Stable Strontium Isotopes

Because of the development of high-precision stable Sr isotope analytical method, stable Sr isotopes have been paid more attention in recent years. Great progress has been made in studies on supergene geochemistry, paleoenvironment, archaeology, endogenesis, and meteorites. This paper summarizes the key techniques of δ88/86Sr analytical methods. Ion exchange method with Eichrom Sr Specific Resin has been widely used to purify Sr. But this specific resin is expensive and may result in contamination during the chromatographic processes. Thus it could be replaced by cation-exchange resin. MC-ICP-MS and TIMS are the instruments for isotope measurement. Normally, MC-ICP-MS has higher measurement efficiency but slightly lower precision than TIMS. Standard-Sample-Bracketing method, Zr-Empirical-External-Normalization method, and double spike method are used to correct the instrumental mass bias. The Double Spike method may have relatively high measurement precision, but there are only a few studies using this method on MC-ICP-MS. Furthermore, there is no detailed comparison of δ88/86Sr of international standard materials. Therefore, optimizing the analysis process, improving the measurement precision, and more determination of δ88/86Sr of standard materials are necessary for the future studies of stable Sr isotopes.