用于多接收器等离子体质谱测定的铁铜锌同位素标准溶液研制

New Standard Solutions for Measurement of Iron, Copper and Zinc Isotopic Compositions by Multi-collector Inductively Coupled Plasma-Mass Spectrometry

近十来年铁铜锌同位素研究已经成为热门研究领域,铁铜锌同位素分析方法日趋成熟,但是铁铜锌同位素标准物质却十分匮乏。目前欧盟参考物质及测量研究所(IRMM)有1个铁同位素标准物质和1个锌同位素标准物质,前者售罄,后者价格昂贵;美国国家标准局(NIST)有1个铜同位素标准物质。为了适应我国铁铜锌同位素研究的发展,本文使用铁铜锌元素浓度标准溶液作为备选标准溶液研制了铁铜锌三个同位素标准溶液(CAGS-Fe、CAGS-Cu和CAGS-Zn)。三个备选标准溶液经过F检验均匀性良好;在38个月内δ56Fe、δ57Fe、δ65Cu、δ66Zn和δ68Zn值没有显著性变化,具有良好的稳定性;主要特性值的推荐值及95%置信水平的不确定度为:CAGS-Fe,δ56FeIRMM014(‰)=0.80±0.05,δ57FeIRMM014(‰)=1.20±0.10;CAGS-Cu,δ65CuIRMM976(‰)=0.57±0.06;CAGS-Zn,δ66ZnIRMM3702(‰)=-0.77±0.10,δ68ZnIRMM3702(‰)=-1.55±0.13。本文研制的标准溶液可用于多接收器等离子体质谱仪测定铁铜锌同位素时的仪器校正和质谱分析过程监控,对于不同实验室的测试数据对比具有重要意义。

In recent decades, Fe, Cu and Zn isotopes have been the hot topic with the development of analytical methods of these isotopes. However, the standard materials for isotope analysis are very sparse. There is only one Fe isotope standard material and one Zn isotope standard in The European Institute for Reference Materials and Measurements （IRMM）. The former is sold out and therefor unobtainable, whereas the latter is expensive. There is one Cu isotope standard material in National Institute of Standards and Technology （NIST）. In order to adapt to the development of Fe, Cu and Zn isotope analyses in China, three new standard solutions to be used as references for Fe, Cu and Zn isotopic composition have been prepared in the Institute of Geology, Chinese Academy of Geological Sciences, Beijing. Fe, Cu and Zn isotopic standard solutions are named CAGS-Fe, CAGS-Cu and CAGS-Zn, respectively. Fe, Cu and Zn isotopic compositions of these standard solutions were measured by high precision Nu Plasma High-resolution Multi-collector Inductively Coupled Plasma-Mass Spectrometry （MC-ICP-MS）. Three standard solutions show high homogeneity and stability by F investigation. The Fe, Cu and Zn isotopic compositions have shown no obvious variations over 38 months, indicating good homogeneity. The reference values for standard solutions and their associated uncertainties at 95% confidence level are 0. 80 ±. 05 （（δ56FelRMM014 ,‰） , 1. 20± 0.10 （δ57FeIRMM014 ,‰） , 0. 57 ±0. 06 （δ65 CUNBS976 ,‰） , - 0.77 ± 0.10 （δ66 ZnIRMM3702 ,‰） and - 1.55 ± 0.13 （δ68ZnIRMM3702 ,‰）. Standard solutions can be used for instrumental calibration and analytical monitoring, which is meaningful for inter-laboratory data comparison.