Compound-Specific Chlorine Isotope Analysis: A Comparison of Gas Chromatography/Isotope Ratio Mass Spectrometry and Gas Chromatography/Quadrupole Mass Spectrometry Methods in an Interlaboratory Study

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• 作者：Anat Bernstein ; Orfan Shouakar-Stash ; Karin Ebert ; Christine Laskov ; Daniel Hunkeler ; Simon Jeannottat ; Kaori Sakaguchi-S枚der ; Jens Laaks ; Maik A. Jochmann ; Stefan Cretnik ; Johannes Jager ; Stefan B. Haderlein ; Torsten C. Schmidt ; Ramon Aravena ; Martin Elsner
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：October 15, 2011
• 年：2011
• 卷：83
• 期：20
• 页码：7624-7634
• 全文大小：986K
• 年卷期：v.83,no.20(October 15, 2011)
• ISSN：1520-6882

文摘

Chlorine isotope analysis of chlorinated hydrocarbons like trichloroethylene (TCE) is of emerging demand because these species are important environmental pollutants. Continuous flow analysis of noncombusted TCE molecules, either by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) or by GC/quadrupole mass spectrometry (GC/qMS), was recently brought forward as innovative analytical solution. Despite early implementations, a benchmark for routine applications has been missing. This study systematically compared the performance of GC/qMS versus GC/IRMS in six laboratories involving eight different instruments (GC/IRMS, Isoprime and Thermo MAT-253; GC/qMS, Agilent 5973N, two Agilent 5975C, two Thermo DSQII, and one Thermo DSQI). Calibrations of ³⁷Cl/³⁵Cl instrument data against the international SMOC scale (Standard Mean Ocean Chloride) deviated between instruments and over time. Therefore, at least two calibration standards are required to obtain true differences between samples. Amount dependency of 未³⁷Cl was pronounced for some instruments, but could be eliminated by corrections, or by adjusting amplitudes of standards and samples. Precision decreased in the order GC/IRMS (1蟽 鈮?0.1鈥?, to GC/qMS (1蟽 鈮?0.2鈥?.5鈥?for Agilent GC/qMS and 1蟽 鈮?0.2鈥?.9鈥?for Thermo GC/qMS). Nonetheless, 未³⁷Cl values between laboratories showed good agreement when the same external standards were used. These results lend confidence to the methods and may serve as a benchmark for future applications.