Major Factors Affecting the Isotopic Measurement of Chlorine Based on the Cs2Cl+ Ion by Thermal Ionization Mass Spectrometry

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• 作者：Yingkai Xiao ; Hai Lu ; Chonggeng Zhang ; Qingzhong Wang ; Haizheng Wei ; Aide Sun ; and Weiguo Liu
• 刊名：Analytical Chemistry
• 出版年：2002
• 出版时间：June 1, 2002
• 年：2002
• 卷：74
• 期：11
• 页码：2458 - 2464
• 全文大小：113K
• 年卷期：v.74,no.11(June 1, 2002)
• ISSN：1520-6882

文摘

The factors that affect isotopic measurement of chlorinebased on Cs₂Cl⁺ ion by thermal ionization mass spectrometry were studied. Graphite is essential for theemission of Cs₂Cl⁺ ion from CsCl. No Cs₂Cl⁺ ions aredetected in the absence of graphite on the filament. Theemission of Cs₂Cl⁺ ion and the measured ³⁷Cl/³⁵Cl ratiowere affected by different varieties of graphite, the pHvalue of the sample solution, and impurities in thesolution. High-precision isotopic measurement of chlorinebased on Cs₂Cl⁺ ion is achieved only by using graphitewith a perfect crystal structure. The measured ³⁷Cl/³⁵Clratios were much higher, and even the emission of Cs₂Cl⁺ ion becomes impossible when pH values of the samplesolution were higher than 6, corresponding to the presence of excess Cs. The measured ³⁷Cl/³⁵Cl ratios werehigher when SO₄^2- and NO₃^- anions were present. Theresults show that the measured ³⁷Cl/³⁵Cl ratios are weaklyrelated to the amount of chlorine on filament in a rangefrom 1 to 500 g.