萤石一次溶样连续分离Rb、Sr、Sm、Nd及Sr-Nd同位素比值TIMS精确测定  

Continual Separation of Rb, Sr,Sm,Nd Elements from Dissolved Fluorite and Accurate Determination of Sr-Nd Isotope Ratio by TIMS

作　　者：张利国 杨梅 杨红梅 张春红 ZHANG Li-Guo;YANG Mei;YANG Hong-Mei;ZHANG Chun-Hong(Wuhan Center,China Geological Survey(Central South China Innovation Center for Geosciences),Wuhan 430205,Hubei,China)

机构地区：[1]中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉430205

出　　处：《华南地质》2022年第4期701-707,共7页South China Geology

基　　金：国家自然科学基金项目(41902053);中国地质调查局项目(DD20221689)。

摘　　要：地质样品中Rb-Sr和Sm-Nd同位素传统分析方法是采用两份样品分别进行Rb-Sr和Sm-Nd分离。本文针对王水溶解后的萤石,采用Dowex50×8阳离子交换树脂和P507离子交换柱的组合,对同一份萤石样品直接溶样,连续分离Rb、Sr、Sm、Nd,并采用该方法对国际标准样品BCR-2中的Rb、Sr、Sm、Nd元素进行分离,然后用表面热电离质谱法(TIMS)进行同位素组成测定。结果表明经该方法连续分离后的样品元素含量及同位素比值测定结果与标样的参考值在误差范围内一致。该方法不仅可以减少样品用量、缩短测试周期、节约成本,而且有效避免了样品的不均一性,对于矿物样品的同位素组成研究具有重要意义。The traditional method of Rb-Sr and Sm-Nd isotope analysis in geological samples usually separates Rb, Sr, Sm and Nd elements from two solutions of the same sample respectively. This study, focused on fluorite dissolved in aqua regia, uses the combination of Dowex50 × 8 Cation exchange resin and HDEHP ion exchange column, and successfully separates the Rb, Sr, Sm and Nd elements continually from the solution.This method has been used on the international standard sample BCR-2 and the isotopic composition of Rb,Sr, Sm and Nd elements is determined by surface thermal ionization mass spectrometry(TIMS). The results show that the element contents and the isotope composition from the samples through the continuous separation are consistent with the reference value of the standard sample within the error. This method not only requires less sample and reagent consumption, but also produces higher efficiency, meanwhile effectively avoiding the heterogeneity of samples, which is especially useful for the study of the isotopic composition of mineral samples.

关 键 词：萤石 Rb、Sr、Sm、Nd同位素 一次溶样 连续分离 Sr-Nd比值TIMS测定 

分 类 号：P597[天文地球—地球化学]