A Common Reference Material for Cadmium Isotope Studies - NIST SRM 3108
A Common Reference Material for Cadmium Isotope Studies - NIST SRM 3108
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DOI：
10.1111/j.1751-908x.2012.00175.x
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发表时间：
2013-03-01
影响因子：
3.8
通讯作者：
Holdship, Philip F.
中科院分区：
文献类型：
--
作者：
Abouchami, Wafa;Galer, Stephen J. G.;Holdship, Philip F.
在过去的几年里，对镉的天然质量依赖稳定同位素分馏的研究迅速扩大。方法是多种多样的，除了一个实验室外，所有实验室都喜欢MC-ICP-MS，该实验室使用热电离质谱法（TIMS）。为了量化同位素分馏和校正仪器质量偏差，使用了双加标技术、样品校准品交叉或元素掺杂。然而，数据集之间的简单比较受到不同实验室中用作零Δ参考的大量内部Cd溶液的阻碍。从长远来看，缺乏合适的镉同位素参考物质不利于研究进展。我们对NIST SRM 3108进行了全面的循环试验，并将Cd同位素偏移量与常用的内部参比物质进行了比较。在这里，我们提倡NIST SRM 3108作为镉的同位素标准和同位素参考点，并鼓励其在未来的研究中作为“零增量”使用。评价了NIST SRM 3108的同质异位素和多原子分子干扰的纯度，发现Zn、Pd和Sn的水平不显著。NIST SRM 3108的Cd-114/Cd-110同位素比在散装硅酸盐土最佳估计值的10 ppm Da（-1）范围内，并对目前使用的所有测量技术进行了验证。
Research into natural mass-dependent stable isotope fractionation of cadmium has rapidly expanded in the past few years. Methodologies are diverse with MC-ICP-MS favoured by all but one laboratory, which uses thermal ionisation mass spectrometry (TIMS). To quantify the isotope fractionation and correct for instrumental mass bias, double-spike techniques, sample-calibrator bracketing or element doping has been used. However, easy comparison between data sets has been hampered by the multitude of in-house Cd solutions used as zero-delta reference in different laboratories. The lack of a suitable isotopic reference material for Cd is detrimental for progress in the long term. We have conducted a comprehensive round-robin assay of NIST SRM 3108 and the Cd isotope offsets to commonly used in-house reference materials. Here, we advocate NIST SRM 3108 both as an isotope standard and the isotopic reference point for Cd and encourage its use as 'zero-delta' in future studies. The purity of NIST SRM 3108 was evaluated regarding isobaric and polyatomic molecular interferences, and the levels of Zn, Pd and Sn found were not significant. The isotope ratio Cd-114/Cd-110 for NIST SRM 3108 lies within similar to 10 ppm Da(-1) of best estimates for the Bulk Silicate Earth and is validated for all measurement technologies currently in use.