地质样品中钛的化学分离及双稀释剂法钛同位素测定  

Titanium Separation and Titanium Isotope Determination by Double-Spike Multicollector-Inductively Coupled Plasma-Mass Spectrometry

作　　者：唐索寒[1,2] 李津[1,2] 马健雄 赵新苗[3] 朱祥坤[1,2] TANG Suo-Han;LI Jin;MA Jian-Xiong;ZHAO Xin-Miao;ZHU Xiang-Kun(Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;MNR Key Laboratory of Isotope Geology,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]自然资源部深地动力学重点实验室,中国地质科学院地质研究所,北京100037 [2]自然资源部同位素地质重点实验室,中国地质科学院地质研究所,北京100037 [3]中国科学院地质与地球物理研究所,岩石圈演化国家重点实验,北京100029

出　　处：《分析化学》2018年第10期1618-1627,共10页Chinese Journal of Analytical Chemistry

基　　金：本文系国家自然科学基金项目(No.41473005)资助。

摘　　要：建立了玄武岩和橄榄岩样品中钛(Ti)的化学分离方法,特别是对于含低Ti而高Fe和Mg的橄榄岩样品中Ti的化学分离方法进行了探索。实现了通过双稀释剂技术校正的多接收器等离子体质谱(MC-ICP-MS)法测定玄武岩和橄榄岩的Ti同位素组成。玄武岩样品Ti的化学分离采用DGA和AG1-X8两柱法;橄榄岩样品Ti的化学分离采用DGA和AG1-X8三柱法。Ti同位素比值使用MC-ICP-MS测定,测定过程中的仪器质量分馏使用双稀释剂法校正。采用SRM 979 Cr同位素标准物质的^(53)Cr/^(52)Cr=0.11339对Ti同位素标准溶液SRM 3162a和^(47)Ti-^(49)Ti双稀释剂进行标定。而后,测定分别加入了^(47)Ti-^(49)Ti双稀释剂的Alfa Ti相对于SRM 3162a Ti的δ^(i/46)Ti,并用于监控测试过程。使用双稀释剂法测定Alfa Ti的结果为:δ^(49/46)Ti=-1.77‰±0.08‰(2sd),δ^(48/46)Ti=-1.20‰±0.05‰(2sd),δ^(47/46)Ti=-0.61‰±0.03‰(2sd),本方法的外部精度≤0.03‰/amu,优于样品-标样交叉法。A method for high-precision isotope measurement of Ti using multi-collector inductively coupled plasma-mass spectrometry(MC-ICP-MS)was developed.Ti separation for isotope measurement was achieved by ion exchange chromatography using Bio-Rad AG 1-X8 anion exchange resin and DGA resin.For the basalt samples,two-column chemistry procedure was used.To get rid of large amounts of Fe and Mg in the peridotite samples,a three-column chemistry procedure was needed.The instrumental mass bias was corrected using 47 Ti-49 Ti Double Spiking and the Ti isotopes were relative to SRM 3162a.Alfa Ti(Ti standard solutions in house)was measured during three measurement sessions over 10 months with a reproducibility of 0.08‰(in terms ofδ^49/46 Ti,2 sd),which was better than that of Standard-Sample Bracketing.

关 键 词：钛同位素 化学分离 双稀释剂 多接收器等离子体质谱 

分 类 号：P597[天文地球—地球化学]