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    高压密闭消解-电感耦合等离子体质谱法测定地球化学样品中6种元素的含量

    Determination of 6 Elements in Geochemical Sample by Inductively Coupled Plasma Mass Spectrometry with High Pressure Sealed Digestion

    • 摘要: 提出了高压密闭消解-电感耦合等离子体质谱法(ICP-MS)测定地球化学样品中硼、钴、钼、镉、锗、铍等6种元素含量的方法。取样品0.100 0 g于聚四氟乙烯坩埚中,加入3 mL 50%王水(体积比为3∶1∶4的盐酸-硝酸-水混合溶液)和0.5 mL氢氟酸,静置30 min后,于180 ℃烘箱中高压消解18 h。消解结束后,用水定容至50 mL,采用ICP-MS测定其中6种元素含量。结果表明:硼、钴元素的质量浓度在200 μg · L−1以内,钼、镉、锗、铍元素的质量浓度在10.0 μg · L−1以内与对应的谱峰强度与内标谱峰强度比呈线性关系,检出限(3s)为0.005~0.12 mg · kg−1;方法用于分析国家标准物质,测定值与认定值基本一致,并且测定值的相对标准偏差(n=12)均小于8.0%;方法用于两个实际地球化学样品的分析,其测定结果与DZ/T 0279—2016的基本一致,且相对标准偏差(n=12)均小于5.0%。

       

      Abstract: A method for determination of 6 elements, including boron, cobalt, molybdenum, cadmium, germanium, and beryllium, in geochemical sample by inductively coupled plasma mass spectrometry (ICP-MS) with high pressure sealed digestion was proposed. 0.100 0 g of the sample was taken into a polytetrafluoroethylene crucible, and 3 mL of 50% aqua regia(a mixture of hydrochloric acid-nitric acid-water at a volume ratio of 3∶1∶4) and 0.5 mL of hydrofluoric acid were added, settling for 30 min. Then the mixture was performed by high pressure digestion in a 180 ℃ oven for 18 h. After digestion, its volume was made up to 50 mL with water, in which 6 elements were determined by ICP-MS. As shown by the results, linear relationships between the corresponding spectral peak intensity and internal standard spectral peak intensity ratios and mass concentrations were found within 200 μg·L−1 for boron and cobalt elements and 10.0 μg·L−1 for molybdenum, cadmium, germanium, and beryllium elements, with detection limits(3s) of 0.005—0.12 mg·kg−1. The method was used to analyze national standard materials, and the determined values were basically consistent with the certified values, with RSDs(n=12) of the determined values less than 8.0%. The method was also used to analyze two actual geochemical samples, and the determined results were basically consistent with those by DZ/T 0279—2016, with RSDs (n=12) less than 5.0%.

       

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