中文摘要：

随着MC-ICP-MS的推广使用,同位素双稀释剂法在国际上已被广泛用于非传统稳定同位素领域中低浓度元素同位素组成的高精度分析,其可有效校正化学纯化和质谱测定过程中的同位素质量分馏,但该方法在国内还未得到全面应用。制约该方法使用的关键在于难以掌握两单稀释剂间（λ）以及双稀释剂与样品之间（p）的最优配比值。本文以Siebert等（2001）的几何迭代算法为例,详细说明了双稀释剂法的计算流程,提出了定性和定量双稀释剂的选择原则,并以硒同位素为例,说明了两单稀释剂间和双稀释剂与样品间最佳配比值的优化步骤,最后简要说明了双稀释剂组成的标定方法、双稀释剂法的优缺点,以及可用于同位素非质量分馏研究的发展趋势。

英文摘要：

With the development and extensive application of multi-collector inductively coupled plasma mass spectrometry（ MC-ICPMS）,the double spike technique（ DS）,which can be used to effectively correct isotope fractionation from chemical purification and mass discrimination,has been widely used in determining isotopic compositions of low concentration geological and environmental samples with high precision requirement. However,this method has not been effectively used by geochemists in China. The key factors limiting to the application of the DS are the proportion of single spike in double spike（ λ） and the proportions of double spike to sample in mix（ p）. In this paper,the method of geometric iterative algorithms developed by Siebert et al.,（ 2001） was selected as an example to introduce calculation procedures of the DS in details. In order to let domestic scholars have a better understanding about the principle and application of the DS,the rules for selecting isotope spike have been qualitatively and quantitatively explained in this paper. Taking selenium isotope as an example,we present the numerically optimized steps for obtaining two key parameters,which are λ and p,of the DS,and a brief description on how to exactly measure the isotopic composition by using the DS,list disadvantage and advantage aspects by using the DS,and give a prospective view on the development trend of the DS method in future for studying mass independent fractionation of non-traditional stable isotopes.