Resolution of inter-laboratory discrepancies in Mo isotope data: an intercalibration
Resolution of inter-laboratory discrepancies in Mo isotope data: an intercalibration
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DOI：
10.1039/c3ja30375f
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发表时间：
2013-01-01
影响因子：
3.4
通讯作者：
Rehkaemper, Mark
中科院分区：
文献类型：
--
作者：
Goldberg, Tatiana;Gordon, Gwyneth;Rehkaemper, Mark
钼稳定同位素体系已被应用于各种地球化学和环境问题。在没有普遍接受的零增量参考材料的情况下，不同的小组报告了相对于其采用的内部标准的数据。只有当内部标准品具有相同的钼同位素组成时，才有可能对不同实验室使用不同分析方法产生的结果进行严格比较。为了确定各种标准品之间的潜在同位素差异，作为本研究的一部分，测量了10种Mo标准品溶液的Δ Mo-98（Mo-98/Mo-95）值。对于其中6种溶液，4个实验室进行了相互校准。与以前的结果相反，发现各种内部标准的Mo-98差值高达0.37 ppm。我们的新的和已发表的Mo同位素数据可用于从各个站点和美国地质勘探局岩石参考材料SDO-1相对于NIST-SRM-3134的海水，提供了一个更好的协议之间的三角洲Mo-98值报告这些样品。相对于NIST-SRM-3134，SDO-1的δ Mo-98为0.80 +/- 0.14千分之一（2s），而好氧公海海水的平均δ Mo-98为2.09 +/- 0.10千分之一（2s）。这种相互校准为比较和修正现有的δ Mo-98值提供了一个坚实的平台。此外，我们建议未来的钼同位素研究采用NIST-SRM-3134作为通用的零δ参考材料。
The molybdenum (Mo) stable isotope system has been applied to a variety of geochemical and environmental problems. In the absence of a universally accepted zero-delta reference material, different groups report their data relative to their adopted in-house standards. Rigorous comparison of results generated in different laboratories using different analytical approaches is only possible if the in-house standards are of identical Mo isotope composition. To determine potential isotopic differences among various standards, the delta Mo-98 (Mo-98/Mo-95) values of ten Mo standard solutions were measured as part of this study. For six of these solutions, four laboratories carried out an intercalibration. In contrast to previous results, delta Mo-98 of various in-house standards were found to differ by up to 0.37 parts per thousand. Renormalisation of our new and published Mo-isotope data available for seawater taken from various sites and the USGS rock reference material SDO-1 relative to NIST-SRM-3134, provides a much better agreement among reported delta Mo-98 values for these samples. Relative to NIST-SRM-3134, the delta Mo-98 of SDO-1 is 0.80 +/- 0.14 parts per thousand (2s), while oxic, open-ocean seawater is characterised by an average delta Mo-98 of 2.09 +/- 0.10 parts per thousand (2s). This intercalibration provides a solid platform for comparing and amending existing delta Mo-98 values. In addition, we recommend that future Mo isotope studies adopt NIST-SRM-3134 as a universal zero-delta reference material.