用质谱技术对钾、钙同位素体系特征参数测定的初探  

Mass Spectrometric Determination of the Special Parameters of the Potassium-Calcium Isotopic System

作　　者：彭子成[1] 王俊新[1] 张巽[1] 刘桂建[1] 贺剑峰[1] 

机构地区：[1]中国科学技术大学地球和空间科学学院

出　　处：《分析化学》2002年第11期1281-1284,共4页Chinese Journal of Analytical Chemistry

基　　金：国家重点基础研究项目 (No .NKBRSF G19990 434 0 1);中国科学院创新工程重大项目 (No .KZCX2 SW 118);国家自然科学基金(No .499730 11)资助课题

摘　　要：报道了用FinniganMAT 2 62质谱技术和同位素稀释法测定了光谱纯CaO和国际二级标准Tahiti(CaCO3)的同位素40 Ca 42 Ca比值以及后者的40 Ca含量 ,RSD分别为 0 .0 2 %和 0 .1 %。对国家钾标样的测定表明 :39K、40 K和41 K同位素丰度分别为 0 .93 2 60± 0 .0 0 1 2、0 0 0 0 1 1 2 0± 0 .0 0 0 0 1 2 9和 0 .0 672 86± 0 .0 0 0 1 2 5。其中39K含量为 0 .1 2 1 72± 0 .0 0 0 2 9,与标准值在误差范围内一致。实验测定结果为在我国开展40 K 40The K-40 similar to Ca-40 isotopic system is important to be used in the geochronology and trace geochemistry. The Ca-40/Ca-42 isotopic ratios and the Ca contents in the CaO reagent and Tahite standard have been determined by using the isotopic dilution mehtod and the Finnigan MAT-262 mass spectrometer. The Ca-40/Ca-42 ratios is 151.43 +/- 0.03 (n = 7) ( standard value: 151.47 +/- 0.03 (n = 5)), while the Ca-40 content in Tahiti is 2.036 +/- 0.003 mumol/g (n = 5) and its relative error between the measured and certified values is +/- 0.13%. The isotopic abundance of K-39, K-40 and K-41 in the national K standard is 0.93260 +/- 0.00012, 0.0001120 +/- 0.0000129 and 0.067286 +/- 0.000125, respectively. The K-39/K-41 ratio of the stable isotopes is 13.860 +/- 0.027 (n = 5), which is consistent to the value of 13.857 +/- 0.006 in the NIST-SRM985 international standard. the precise determination of the special parameters in the K-Ca system is the foundation of timing and tracing study in the future time.

关 键 词：特征参数 测定 钾 钙 同位素体系 质谱 同位素稀释法 同位素丰度 标准样品 

分 类 号：O657.63[理学—分析化学]