一种快速同位素稀释定量方法及其在示踪方面的应用  

An Efficient Isotopic Dilution Method and Its Application in Tracing Technology

作　　者：方随 李志明[1] 徐江[1] 汪伟 翟利华[1] 邓虎[1] 韦冠一[1] FANG Sui;LI Zhi-Ming;XU Jiang;WANG Wei;ZHAI Li-Hua;DENG Hu;WEI Guan-Yi(Northwest Institute of Nuclear Technology,Xi′an 710024,China)

机构地区：[1]西北核技术研究所,西安710024

出　　处：《分析化学》2020年第11期1542-1549,I0033,I0034,共10页Chinese Journal of Analytical Chemistry

基　　金：科技部重大仪器专项项目(2012YQ250003)资助。

摘　　要：同位素稀释法定量分析中,当待测样品中某一目标同位素的丰度被示踪剂影响而不能保持天然丰度时,需要测量样品中各同位素的丰度比。在待测样品量或测量时间有限时,常规同位素稀释法的应用受到局限。为了降低样品消耗量、简化测量步骤、减小记忆效应影响、提高测量效率,本研究建立了一种可省略待测样品丰度比测量环节的快速同位素稀释定量方法。基于物质的量守恒原理,通过关联的运算,得到待测样品后,只需进行一次添加同位素稀释剂后混合样品的丰度比测量即可完成目标同位素的定量分析。以天然丰度Xe标准气体作为模拟样品,6次测量值与标称值的相对偏差均小于1%,相对标准偏差(RSD)为0.4%,与使用常规同位素稀释法得到的测量结果完全相符。此外,以128 Xe作为示踪同位素,得到的示踪同位素扩散曲线符合气体在封闭空间的扩散规律。本方法适用于有3种或更多稳定同位素的元素,既保证了测量结果的准确性,又可缩短分析时间,减少样品消耗量。In conventional isotopic dilution method,when target isotope in a sample is influenced by the tracing material,it should be measured includes not only the isotope ratios of the mixture of dilution and sample,but also that of the original sample.In case that sample is insufficient,or measuring time is limited,the isotope dilute method meets its embarrassment.In this study,an efficient quantitative isotopic dilution method was provided,in which the measurement of the isotope ratios in the sample was unnecessary.This method had particularly advantage on reducing sample consumption,simplifying the measurement procedure and decreasing the influence of memory effect,which greatly improved the efficiency of the measurement.The six measurements showed that xenon standard gas was used to verify its applicability,which provided a bias of less than 1%to the nominal value and a relative standard deviation(RSD)of 0.4%.The measurement result was completely consistent with the value of conventional isotope dilution.In tracing experiment with 128 Xe,despite of the interference of natural xenon,128 Xe of tracer was precisely determined.The diffusion curve which was drawn by 128 Xe,also accorded with the rule of gas diffusion in the closed space.This method was suitable only for elements that with three or more isotopes.

关 键 词：同位素稀释 定量 快速 示踪 

分 类 号：O613.15[理学—无机化学]