文中阐述并归纳了近年地质样品中铂族元素的分离、富集及测试方法方面的最新进展。铂族元素本身的超痕量性,要求实验过程中对空白值的控制,干扰元素的扣除和检测限的降低更为严格,同时要克服块金效应。文中对消解过程中常用的火试金法、酸溶、碱熔方法和卡洛斯管法(Carius tube),分离富集过程中的Te共沉淀和离子交换法,测试手段中的原子光谱法、中子活化法和等离子质谱法等方法的最新进展进行了总结。由于复杂的地质样品中PGE的浓度范围不一、赋存形式多样,要求在具体样品分析过程中灵活地搭配使用各种分离富集和检测方法,结合笔者所在实验室在实验过程中发现的问题,对各种不同类型地质样品中铂族元素的分离富集、样品处理及测定方法也进行了总结。
Recent advances in sample digestion, separation and instrumental measurement for analysis of platinum group elements (PGE) in geological samples are reviewed. The low concentration of the PGE in most of the geological samples and their heterogeneous distributions (nugget effect) make accurate determination of PGE very difficult. Separation of PGE from sample matrix are required to reduce nugget effect, to minimize the blank level and detection limits, and to avoid interferences. Fire assay, acid treatment, alkali fusion and Carius tube techniques for digesting geological samples, tellurium coprecipitation and ion exchange methods for separating PGE from the matrix, atomic absorption spectrometry(AAS), inductively coupled plasma atomic emission spectrometry(ICP-AES), instrumental neutron activation analysis(INAA) and inductively coupled plasma mass spectrometry (ICP-MS) for determination of PC-E, are reviewed in this paper. Because of the diverse contentsand distributions of PGE in geological samples, the analytical methods should be used suitably for routine analysis. According to the advantages and disadvantages of each method and the experience of our laboratory, this paper also summarizes the suitable digestion and pre-concentrating methods for different geological sampies.