介绍了一种简单的辉钼矿Re-Os同位素定年中Re的化学分离方法,采用“钽试剂”(N-苯甲酰基苯基羟胺)的氯仿溶液萃取辉钼矿中的主要基体和干扰元素,如Mo、Fe和W,达到Re与这些主要基体元素分离的目的。在此基础上,建立了Carius管溶样-四氯化碳萃取分离Os-“钽试剂”萃取分离Re以及同位素稀释电感耦合等离子体质谱法测定的分析流程。利用该分析流程,对辉钼矿标准物质JDC进行Re-Os同位素年龄测定研究,测得其Re、Os的平均含量及年龄分别为(17.6±0.2)μg/g、(25.9±0.3)ng/g和(140.1±2.4)Ma,该结果在误差范围内与标准参考值一致。与目前常用的辉钼矿Re-Os同位素定年方法相比,该方法具有操作简便、快速、高效以及成本低的优势,非常适合作为辉钼矿Re-Os同位素定年的化学分离常规方法。
In this study, we introduced a simple method for chemical separation of Re for molybdenite Re-Os dating. N-benzoyl-N-phenylhydroxylamine (BPHA) in chloroform solution was employed for the removal of Mo, and W which are major elements in molybdenite. An analytical procedure is established based on the Carius tube digestion and carbon tetroxide (CCl4) extraction of Os, BPHA extraction for the separation of Re, then Re and Os concentrations are measured by isotope dilution-inductively coupled plasma mass spectrometry (ICP-MS). The analytical procedure was applied to the determination of the Re-Os dating molybdenite reference materials (JDC), the contents of Re, Os and ages for JDC were (17.6±0.2) 0μ/g, (25.9±0.3) ng/g and (140. 1 ±2.4) Ma, respectively. These results are in agreement with the reference values. The characteristics of the method, i.e., comparative simplicity, efficiency, a shorter period and lower cost, make it especially suitable for routine analysis.