离子交换树脂在地质样品Sr-Nd同位素测定中的应用

The Application of Ion Exchange Resins in Sr-Nd Isotopic Assay of Geological Samples

Rb-Sr和Sm-Nd同位素测年及同位素示踪方法在同位素地质年代学和同位素地球化学中有非常广泛的应用。目前,Rb-Sr和Sm-Nd同位素质谱测试方法通常需要对Rb、Sr和Sm、Nd进行分离纯化,因此,如何对地质样品中的Rb、Sr、Sm和Nd进行分离富集对测试结果准确与否起到至关重要的作用。离子交换分离法是SrNd同位素化学前处理阶段应用最广泛的分离方法,本文结合笔者近几年的研究工作,系统介绍离子交换树脂在Sr-Nd同位素测试中应用的发展过程和现状,重点介绍几类使用率较高的离子交换树脂(Dowex50W树脂、AG50W树脂、锶特效树脂、LN树脂、P507树脂等)的优缺点,以及各自的萃取反应机理,探索和讨论未来离子交换树脂在Sr-Nd同位素测试中应用的发展趋势。

Rb-Sr and Sm-Nd isotopic dating and isotopic tracer method are widely applied in both isotopic geochronology and isotope geochemistry.At present,it is necessary to isolate and purificate Rb-Sr and Sm-Nd for the analysis of Rb-Sr and Sm-Nd by isotope mass spectrometry.Therefore how to isolate and enrich Rb,Sr,Sm and Nd in geological samples plays an important role in improving the accuracy of the analysis results.Ion exchange separation method is most widely used in the pre-processing stage of isotope chemistry.Combining with the author′s research in recent years,the development and status of ion exchange separation method applied in isotope analysis was summarized systematically in this paper.In particular,we focus on describing the advantages and disadvantages of some kinds of ion exchange resins（Dowex50 Wresin;AG50 Wresin;Strontium spec resin;Ln Spec resin;P507 resin）,and their extraction mechanism.At last,this study discusses the development trend of ion exchange resin applied in Sr-Nd isotope analysis.