碱熔-阳离子交换树脂分离ICP-MS法测定厚覆盖区地球化学调查样品中硼锗溴钼锡碘钨

多目标地球化学填图是多目标区域地球化学调查中重要的区域性基础性工作之一，为了更好地反映出地球化学背景变化，要求分析方法具有更高的准确度、精密度以及更低的检出限。地球化学调查样品中的硼锗溴钼锡碘钨主要采用单独或分组熔矿的方法进行制备和测定，操作流程长且涉及6种测定方法。本文基于前人研究，对以上7种元素的分析方法进行系统总结，采用过氧化钠-氢氧化钠碱熔，分取溶液加入柠檬酸，利用阳离子交换树脂，静态交换2～3h,除去溶液中大量的阳离子减少基体干扰，利用电感耦合等离子体质谱法(ICP-MS)测定硼锗溴钼锡碘钨含量。结果表明：7种元素的检出限分别为0.66、0.096、0.78、0.11、0.15、0.29、0.27μg/g,相对标准偏差(RSD,n=11)在2.1%～7.5%之间，均小于10%。该方法操作简便、快速，应用成本低，并且整合了相关6种分析配套方法，应用于测定厚覆盖区地球化学调查样品，精密度和准确度均满足《多目标区域地球化学调查规范(1∶250000)》(DZ/T 0258—2014)要求。

Determination of Boron, Germanium, Bromine, Molybdenum, Tin, Iodine and Tungsten in Geochemical Survey Samples by ICP-MS with Alkali Fusion-Cation Exchange Resin Separation

BACKGROUND:Multi-target geochemical mapping is one of the most important basic regional tasks in multi-target regional geochemical surveys.In order to better reflect changes in the geochemical background,analytical methods are required to have higher accuracy and precision,and lower detection limits.Elements B,Ge,Br,Mo,Sn,I,and W in geochemical survey samples are mainly prepared and determined by smelting ore individually or in groups.The analysis procedure is long and involves 6 methods.OBJECTIVES:In order to integrate 6 supporting analysis methods,optimize analysis conditions,and improve the accuracy and precision of the method.METHODS:The mixed reagent of sodium peroxide and sodium hydroxide was used for alkali fusion.Citric acid was added to the solution.Cation exchange resin was used for static exchange for 2-3 hours to remove a large amount of cations in the solution and reduce matrix interference.B,Ge,Br,Mo,Sn,I,and W were determined using inductively coupled plasma mass spectrometry.RESULTS:The detection limits of B,Ge,Br,Mo,Sn,I,and W were 0.66,0.096,0.78,0.11,0.15,0.29,and 0.27μg/g,respectively.Relative standard deviation(RSD,n=12)was between 2.1%and 7.5%,which were all less than 10%.CONCLUSIONS:The method is simple,rapid and low-cost,and its precision and accuracy meet the requirements of《Specification of multi-purpose regional geochemical survey(1∶250000)》(DZ/T 0258—2014).It can quickly and accurately determine B,Ge,Br,Mo,Sn,I,W in geochemical survey samples in a thick coverage area.