A redetermination of the isotopic abundances of atmospheric Ar
A redetermination of the isotopic abundances of atmospheric Ar
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DOI：
10.1016/j.gca.2006.06.1563
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发表时间：
2006-09-01
影响因子：
5
通讯作者：
Kim, Jin Seog
中科院分区：
文献类型：
--
作者：
Lee, Jee-Yon;Marti, Kurt;Kim, Jin Seog
在带有离子源磁铁的动态操作质谱仪上测量的大气氩，其Ar - 40/Ar - 16比值系统地高于尼尔（Nier A.O., 1950. 碳、氮、氧、氩和钾同位素相对丰度的重新测定。《物理评论》77, 789 - 793）所给出的普遍接受的值295.5 ± 0.5，该值一直是地球化学和宇宙化学中所有同位素测量的标准。利用重量法制备的高浓缩Ar - 36和Ar - 40混合物，通过一台经过微小改进且采用特殊气体处理技术以避免分馏的动态操作同位素比质谱仪，重新测定了大气氩的同位素丰度。得到了一个新的比值Ar - 40/Ar - 36 = 298.56 ± 0.31，精度为0.1%，比先前接受的值大约高1%。结合在静态操作下用VG5400惰性气体质谱仪测量的Ar - 38/Ar - 36（0.1885 ± 0.0003），确定Ar - 36、Ar - 38和Ar - 40的百分比丰度分别为0.3336 ± 0.0004、0.0629 ± 0.0001和99.6035 ± 0.0004。我们计算出氩的原子质量为39.9478 ± 0.0002。准确的氩同位素丰度在许多应用中都很重要，例如质谱仪歧视效应的校准。（c）2006爱思唯尔公司。保留所有权利。
Atmospheric argon measured on a dynamically operated mass spectrometer with an ion source magnet, indicated systematically larger Ar-40/Ar-16 ratios compared to the generally accepted value of Nier [Nier A.O., 1950. A redetermination of the relative abundances of the isotopes of carbon, nitrogen, oxygen, argon, and potassium. Phys. Rev. 77, 789-793], 295.5 +/- 0.5, which has served as the standard for all isotopic measurements in geochemistry and cosmochemistry. Gravimetrically prepared mixtures of highly enriched Ar-36 and Ar-40 were utilized to redetermine the isotopic abundances of atmospheric Ar, using a dynamically operated isotope ratio mass spectrometer with minor modifications and special gas handling techniques to avoid fractionation. A new ratio Ar-40/Ar-36 = 298.56 +/- 0.31 was obtained with a precision of 0.1%, approximately 1% higher than the previously accepted value. Combined with the Ar-38/Ar-36 (0.1885 +/- 0.0003) measured with a VG5400 noble gas mass spectrometer in static operation, the percent abundances of Ar-36, Ar-38, and Ar-40 were determined to be 0.3336 +/- 0.0004, 0.0629 +/- 0.0001, and 99.6035 +/- 0.0004, respectively. We calculate an atomic mass of Ar of 39.9478 +/- 0.0002. Accurate Ar isotopic abundances are relevant in numerous applications, as the calibration of the mass spectrometer discrimination. (c) 2006 Elsevier Inc. All rights reserved.