title: Major factors affecting the isotopic measurement of chlorine based on the Cs2Cl+ ion by thermal ionization mass spectrometry.
abstract: The factors that affect isotopic measurement of chlorine based on Cs2Cl+ ion by thermal ionization mass spectrometry were studied. Graphite is essential for the emission of Cs2Cl+ ion from CsCl. No Cs2Cl+ ions are detected in the absence of graphite on the filament. The emission of Cs2Cl+ ion and the measured 37Cl/35Cl ratio were affected by different varieties of graphite, the pH value of the sample solution, and impurities in the solution. High-precision isotopic measurement of chlorine based on Cs2Cl+ ion is achieved only by using graphite with a perfect crystal structure. The measured 37Cl/35Cl ratios were much higher, and even the emission of Cs2Cl+ ion becomes impossible when pH values of the sample solution were higher than 6, corresponding to the presence of excess Cs. The measured 37Cl/35Cl ratios were higher when SO4(2-) and NO3- anions were present. The results show that the measured 37Cl/35Cl ratios are weakly related to the amount of chlorine on filament in a range from 1 to 500 microg.
authors.affiliation: Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining. qhyhyjs@public.xn.qh.cn
authors.forename: Yingkai
authors.initials: Y
authors.lastname: Xiao
authors.forename: M Hai
authors.initials: MH
authors.lastname: Lu
authors.forename: Chonggeng
authors.initials: C
authors.lastname: Zhang
authors.forename: Qingzhong
authors.initials: Q
authors.lastname: Wang
authors.forename: Haizheng
authors.initials: H
authors.lastname: Wei
authors.forename: Aide
authors.initials: A
authors.lastname: Sun
authors.forename: Weiguo
authors.initials: W
authors.lastname: Liu