The development of sample preparation for the determination of Si isotopic abundances ratios with gas-source mass-spectrometry is introduced. The single crystal silicon is converted to SiO2 based on alkaline solution digestion followed by cation-exchange column and calcinating at 850℃. After dissolving SiO2 with HF acid, H2SiF6 solution is obtained . BaSiF6 precipitation is formed by drop adding BaCl2 solution. Then BaSiF6 is decomposed to SiF4 and Si isotope ratios is measured by gas-source mass-spectrometry. By Optimizing the sample preparation procedure, high recovery SiF4gas is obtained. The results indicate that the sample preparation method for the determination of Si isotopic abundances ratios has high repeatability and recovery, meeting the requirement for the accurate measurement of silicon molar mass.%介绍了气体同位素比值质谱法测定硅同位素丰度比的样品制备方法.采用碱溶法溶解单晶硅样品,经阳离子交换反应、烘干焙烧制得二氧化硅,再用氢氟酸溶解二氧化硅得到氟硅酸溶液,进一步滴加氯化钡溶液生成氟硅酸钡沉淀,将氟硅酸钡热分解最终制得四氟化硅气体.通过优化制备工艺条件,获得了高收率的四氟化硅气体,采用气体同位素比值质谱仪测定四氟化硅气体硅同位素丰度比.测量结果表明,该方法制备出的四氟化硅气体用于硅同位素丰度的测量,具有再现性好,回收率达到了97％以上,能满足准确测量硅摩尔质量的要求.
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