An improved chemical method is developed to accurately measure the W isotopic compositions of silicate samples with a precision of better than ±0.05ε on ε¹⁸²W. Compared with the conventional method, two developments of this method mainly include the sample digestion process that is modified to better W dissolution from the co-precipitations and the W separation procedure. The optimized extraction chromatography using TEVA resin is designed to more efficiently separate W from Ti, Zr and Hf after the first-stage cation-exchange procedure with the percent recovery of W more than 85%. The blank during the whole procedure is less than 0.3 ng and is negligible for W isotopic analysis. The W isotopic ratios of Alfa Aesar W standard solution and a variety of silicate reference materials, i.e., RGM-2, GSP-2, AGV-2, JB-3, BCR-2 and BHVO-2, are measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). RGM-2, GSP-2, AGV-2, JB-3 and BCR-2 have normal ε¹⁸²W values, identical to that of the terrestrial Alfa Aesar W standard, whereas BHVO-2 has a negative ε¹⁸²W value of −0.09 ± 0.05 (2SD, N = 10). The duplicate measurements of Alfa Aesar W standard solution RGM-2 and BHVO-2 show that the external reproducibility of ε¹⁸²W is usually better than 5 ppm (2SD), which is the most precise among the published data measured by MC-ICPMS and can be comparable to the precision acquired by negative thermal ionization mass spectrometry (N-TIMS) (about 5 ppm). All these results show that our new method provides an efficient way to precisely measure W isotopic compositions of silicate materials. It provides a widely useful tool to reveal the earliest history of the silicate earth and offers the ability to resolve sub-million-year age differences in meteorites.

中文翻译：

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使用MC-ICPMS改进了从硅酸盐基质中提取钨的色谱法，用于高精度同位素测量†

的改进的化学方法显影，以精确地测量硅酸盐样品在W同位素组成以优于±0.05的精度ε上ε ¹⁸²W.与常规方法相比，此方法的两个发展主要包括样品消解过程，该过程经过了改进，可以更好地从共沉淀和W分离过程中溶解W。经过优化的使用TEVA树脂的萃取色谱法旨在在第一步阳离子交换程序后更有效地将W从Ti，Zr和Hf中分离出来，W的回收率超过85％。整个过程中的空白小于0.3 ng，对于W同位素分析可以忽略不计。Alfa Aesar W标准溶液和多种硅酸盐标准物质的W同位素比，即RGM-2，GSP-2，AGV-2，JB-3，BCR-2和BHVO-2是通过多收集器电感耦合等离子体质谱法（MC-ICP-MS）测量的。RGM-2，GSP-2，AGV-2，JB-3和BCR-2具有正常ε ¹⁸²的W值，等同于地面阿法埃莎W¯¯标准的，而BHVO-2具有负ε ¹⁸²的W值- 0.09±0.05（2SD，N = 10）。阿法埃莎的重复测量W¯¯标准溶液RGM-2和BHVO-2显示的外部再现ε ¹⁸²W通常优于5 ppm（2SD），这是通过MC-ICPMS测量的已发布数据中最精确的值，可以与通过负热电离质谱法（N-TIMS）获得的精度（约5 ppm）相媲美。所有这些结果表明，我们的新方法为准确测量硅酸盐材料的W同位素组成提供了一种有效的方法。它提供了一个广泛有用的工具来揭示硅酸盐地球的最早历史，并具有解决陨石中亚百万年年龄差异的能力。