摘要
为了使国内研究人员更为深入的了解双稀释剂法的原理和应用,本文以^(74)Se+^(77)Se双稀释剂为例,详细介绍了双稀释剂法在应用过程中所涉及的双稀释剂配比优化、标定及高精度数据获取的方法和流程。并分别通过蒙特-卡洛数值优化方法和实测数据对^(74)Se+^(77)Se双稀释剂进行了配比的优化,得到了两单稀释剂间和双稀释剂与样品间最佳的取值范围:当^(74)Se_(spk)/^(77)Se_(spk)≈1时,^(77)Se_(spike)/^(78)Se_(sample)≈2为最优配比值,但^(77)Se_(spike)/^(78)Se_(sample)在1~4范围内,硒同位素的分析精度不受影响。基于双稀释的优化结果,对NIST SRM 3149、MH495、GBW(E)080215三种Se的标准溶液进行长期测定,相对于NIST SRM3149,δ^(82/76)Se值分别为0.00‰±0.10‰(2SD,n=65),-3.44‰±0.08‰(2SD,n=21)和-7.90‰±0.10‰(2SD,n=21)。通过与标准-样品匹配法和元素内标法获取的数据进行对比,双稀释剂法获取的数据具有更高的准确度和精密度,这为自然界微小同位素分馏过程的研究奠定了基础。
In order to let domestic researchers to deeply understand the principle and application of the isotopic double spike technique, methods and procedures for the proportion optimization and calibration of the double spike and the high precision data acquisition, which are associated with the application of the isotopic double spike technique, have been de- tailly introduced in this paper by taking the74Se＋77Se double spike as an example. On the basis of the result of the Monte Carlo numerical optimization and measured data, the proportion optimization for the74Se＋77Se double spike has been car- ried out. It is obtained that optimized ratios between the double spike and sample is about 2 （77Se pike/78Sesampl≈2）when the ratio between two single diluents is about 1 （ 74Sespk//77Sespk ≈ 1 ） . If the 77Sespike/78Sesample ratios vary from 1 to 4, the an- alytical precision of Se isotopic values（882/76Se） is unaffected. Based on the accurate proportion optimization of the DS, the long-term measured bSEZ76Se values of the three standard solutions of NIST SRM 3149, MH495 and GBW （E）080215 are 0.00‰±0. 10‰ （ 2SD, n = 65）, -3.44‰±0.08‰ （ 2SD, n = 21 ）, and -7.88‰±0. 10‰ （ 2SD, n = 21 ）, respectively. Comparing to data obtained by using the standard-sample matching method and the inside element method, the data ob- tained by using the double spike technique have relative high accuracy and precision Therefore, the application of double spike can lay the foundation for studying small isotope fractionation process in nature.
出处
《矿物岩石地球化学通报》
CSCD
北大核心
2017年第6期948-954,共7页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金项目(41473028)
国家重点基础研究发展计划项目(2014CB238903)
