Precise determination of triple Sr isotopes (δ⁸⁷Sr and δ⁸⁸Sr) using MC-ICP-MS.
Precise determination of triple Sr isotopes (δ⁸⁷Sr and δ⁸⁸Sr) using MC-ICP-MS.
复制标题
DOI：
10.1016/j.talanta.2011.10.050
复制
发表时间：
2012-01
期刊：
影响因子：
6.1
通讯作者：
Hou-Chun Liu;C. You;Kuo‐Fang Huang;C. Chung
中科院分区：
文献类型：
--
作者：
Hou-Chun Liu;C. You;Kuo‐Fang Huang;C. Chung
非传统稳定锶同位素作为一种新的地球化学示踪剂，在锶同位素分馏和来源鉴定方面受到越来越多的关注。这要归功于多收集器电感耦合等离子体质谱法（MC-ICP-MS）的进步，它可以同时精确地测定三种锶同位素。在本研究中，我们应用改进的经验外部归一化（EEN） MC-ICPMS程序对使用92zr /90Zr测量Sr同位素的质量偏差进行校正。将高纯度Zr标准品加入样品溶液中，采用指数法离线计算分馏度。NIST SRM 987 δ87Sr和δ88Sr的长期外部重现性分别优于0.040‰和0.018‰（2SD）。采用IAPSO标准海水作为二级标准品对分析方案进行验证，测得的绝对比值87sr /86Sr为0.709161±0.000018，δ87Sr为0.177±0.021‰，δ88Sr为0.370±0.026‰（2SD, n=7）。这些数值与热电离质谱（TIMS）双峰技术分析的文献数据吻合较好。对岩石标准、BHVO-2、BCR-2和AGV-2进行了分析，验证了方法的稳健性，并显示了与文献数据相同的结果。与之前的91zr /90Zr校正相比，我们基于92zr /90Zr得到了改进的结果，这可能是由于92zr /90Zr与测量的Sr同位素之间的质量差相似。本研究提出的新分析方案不仅提高了分析精度，而且通过省略标准样品包封（SSB）程序提高了样品效率。
The non-traditional stable strontium (Sr) isotopes have received increasing attention recently as new geochemical tracers for studying Sr isotopic fractionation and source identification. This has been attributed to the advancement in multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), allows to determine precisely and simultaneously of the triple Sr isotopes. In this study, we applied a modified empirical external normalization (EEN) MC-ICPMS procedure for mass bias correction in Sr isotopic measurement using92Zr/90Zr. High-purity Zr Standard was spiked into sample solutions and the degree of fractionation was calculated off-line using an exponential law. The long-term external reproducibility for NIST SRM 987 δ87Sr and δ88Sr was better than 0.040‰ and 0.018‰ (2SD), respectively. The IAPSO standard seawater was used as a secondary standard to validate the analytical protocol and the absolute ratios measured were 0.709161±0.000018 for87Sr/86Sr, 0.177±0.021‰ for δ87Sr, and 0.370±0.026‰ for δ88Sr (2SD, n=7). These values are in good agreement with the literature data analyzed by thermal ionization mass spectrometry (TIMS) double spike technique. Rock standards, BHVO-2, BCR-2 and AGV-2 were also analyzed to validate the robustness of the methodology and showed identical results with literature data. Compared to previous91Zr/90Zr correction, we obtained improved results based on92Zr/90Zr, probably due to similar mass difference between92Zr/90Zr and measured Sr isotopes. The new analytical protocol presented in this study not only improves the analytical precision but also increases sample efficiency by omitting the use of the standard-sample bracketing (SSB) procedure.