Zhai Hua-Ye, Wang Xuan-Ce, Li Chao-Feng, Wilde Simon A, Li Xiang-Zhong, Xu Bei, Zhang Xian-Liang, Zhang Ping
Yunnan University Kunming 650504 China
School of Earth and Environmental Sciences, The University of Queensland QLD 4072 Australia.
RSC Adv. 2023 Jun 28;13(28):19030-19038. doi: 10.1039/d3ra00603d. eCollection 2023 Jun 22.
Zinc isotopic ratios serve as powerful tools for tracing biochemical cycling of metals at Earth's surface, including the distribution, transportation, and enrichment of zinc (Zn) in soil. To conduct such studies and enable inter-laboratory comparisons, high-precision Zn isotopic measurements require the use of soil reference materials (RMs). However, there have been limited reports on the high-precision Zn isotope ratios of soil RMs thus far. In this study, we have developed a two-step Zn chemical separation protocol utilizing Bio-Rad AG MP-1M resin columns. This method has demonstrated excellent reproducibility for measuring the external Zn values (relative to JMC-Lyon) of standard soil reference materials over an extended time period, with a better than 0.06‰ (2SD) precision. Remarkably, this study is the first to report the Zn isotopic compositions of 20 soil reference materials from various soil types in China. With the exception of one sample obtained from a mining area, the Zn isotopic compositions of all the analyzed soil reference materials exhibit remarkable similarity, with an average Zn value of 0.31 ± 0.12‰, which aligns closely with the values observed in igneous rocks. The exceptional sample, with a higher Zn value of 0.61 ± 0.02‰, indicates potential contamination during mining activities.
锌同位素比值是追踪地球表面金属生物化学循环的有力工具，包括锌（Zn）在土壤中的分布、运输和富集。为了开展此类研究并实现实验室间的比较，高精度锌同位素测量需要使用土壤标准物质（RMs）。然而，迄今为止，关于土壤标准物质高精度锌同位素比值的报道有限。在本研究中，我们开发了一种利用伯乐AG MP-1M树脂柱的两步锌化学分离方案。该方法在较长时间内对标准土壤标准物质的外部锌值（相对于JMC-Lyon）测量显示出优异的重现性，精度优于0.06‰（2SD）。值得注意的是，本研究首次报道了中国20种不同土壤类型土壤标准物质的锌同位素组成。除了一个来自矿区的样品外，所有分析的土壤标准物质的锌同位素组成都表现出显著的相似性，平均锌值为0.31±0.12‰，这与火成岩中观察到的值密切一致。这个异常的样品锌值较高，为0.61±0.02‰，表明采矿活动期间可能存在污染。
