天然硅酸岩铷锶同位素稀释测定小交换柱化学制备方法研究

本篇报道用于铷锶同位素年代测量的小柱分析流程。方法是在我们1972年草酸淋洗流程的基础上建立的。同时参考W.康普斯敦教授1977年介绍的小交换柱铷锶化学流程。样品提取方式、交换柱分离条件和操作步骤,是根据自己的实验确定的。流程有自身的特点。

STUDY ON THE SMALL COLUMN CHEMICAL PROCEDURE FOR THE DILUTION DETERMINATION OF THE RUBIDIUM AND STRONTIUM ISOTOPES IN NATURAL SILICATE ROCKS

The chemical procedure described in this paper was designed to meet two requirements: (a) it should be applicable to various kinds of natural silicate rocks,and (b) it should ensure the separation and purification of rubidium and strontium in a single run of ion exchange procedure.Samples are dissolved in mixed HF-HCIO₄ acid,and then heated to decompose perchlorites of Fe,Al,Mg into oxides which are subsequently removed by centrifugal separation after adding about 5ml of deionized water in the solution and being boiled.The use of this procedure will considerably simplify the composition of the ion exchange solution and,on the other hand,greatly increase the ratio of the total volume of cation exchange to the total content of cations in the equilibrium system and hence facilitate the process of ion separation.We used 0.3 N HC1,0.5 N HC1 mixed with 0.2M oxalic acid,and 1.25 N HC1 to rinse away ions of alkali elements,Fe and Al,and alkaline earth elements,respectively,resulting in good separations among Na-K-Rb,Mg-Ca-Sr,and Rb-Mg,Rb-Sr and Al-Sr,respectively.This procedure was proved to be successful by more than 300 analyses of samples of granites to mafic rocks and olivine.