College of Chemistry, Sichuan University, Chengdu 610064, China.
National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada.
Anal Chem. 2020 Apr 21;92(8):6103-6110. doi: 10.1021/acs.analchem.0c00531. Epub 2020 Apr 8.
In this study, we report independent measurements of all stable isotope ratios of gadolinium. Our study employs multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) with National Research Council Canada (NRC) HALF-1 isotopic hafnium standard as a primary calibrator and surveys four commercial gadolinium materials, including a NRC candidate isotopic reference material, GADS-1. The isotopic composition of gadolinium is determined using the regression model without reliance on conventional normalizing isotope ratios or mass-dependent isotope ratio correction models. In this work, all gadolinium isotope ratios were obtained from Gd/Gd which, in turn, was measured from hafnium Hf/Hf either directly or indirectly through Er/Er. The latter approach was used for the final determination of gadolinium isotopic composition, as it provides smaller combined uncertainty. We report high-precision measurements of the isotopic composition of gadolinium, which support a revised standard atomic weight. Isotope amount ratios of = 0.008 20(2), = 0.087 98(12), = 0.596 81(63), = 0.825 08(57), = 0.630 60(22), and = 0.879 10(60), and the atomic weight of (Gd) = 157.2502(6) were obtained for gadolinium in GADS-1.
在本研究中，我们报告了对所有稳定的钆同位素比值的独立测量结果。我们的研究采用多接收电感耦合等离子体质谱（MC-ICPMS），以加拿大国家研究委员会（NRC）HALF-1 同位素铪标准作为主要校准标准，并对四种商业钆材料进行了调查，包括 NRC 候选同位素参考材料 GADS-1。钆的同位素组成是使用回归模型确定的，不依赖于传统的归一化同位素比值或质量依赖的同位素比值校正模型。在这项工作中，所有的钆同位素比值都是从 Gd/Gd 获得的，而 Gd/Gd 又是通过直接或间接通过 Er/Er 从 Hf/Hf 测量得到的。后一种方法用于最终确定钆的同位素组成，因为它提供了更小的综合不确定度。我们报告了对钆同位素组成的高精度测量结果，这支持了修订后的标准原子量。 = 0.008 20(2)、 = 0.087 98(12)、 = 0.596 81(63)、 = 0.825 08(57)、 = 0.630 60(22)和 = 0.879 10(60)的同位素丰度比，以及 (Gd) = 157.2502(6)的原子量，是从 GADS-1 中的钆获得的。
