Compound-Specific Chlorine Isotope Analysis of Tetrachloromethane and Trichloromethane by Gas Chromatography-Isotope Ratio Mass Spectrometry vs Gas Chromatography-Quadrupole Mass Spectrometry: Method Development and Evaluation of Precision and Trueness.
Compound-Specific Chlorine Isotope Analysis of Tetrachloromethane and Trichloromethane by Gas Chromatography-Isotope Ratio Mass Spectrometry vs Gas Chromatography-Quadrupole Mass Spectrometry: Method Development and Evaluation of Precision and Trueness.
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DOI：
10.1021/acs.analchem.6b04129
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发表时间：
2017-03
影响因子：
7.4
通讯作者：
Benjamin Heckel;Diana Rodríguez-Fernández;C. Torrentó;A. Meyer;J. Palau;C. Domènech;M. Rosell;A. Soler;D. Hunkeler;M. Elsner
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文献类型：
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作者：
Benjamin Heckel;Diana Rodríguez-Fernández;C. Torrentó;A. Meyer;J. Palau;C. Domènech;M. Rosell;A. Soler;D. Hunkeler;M. Elsner
通过气相色谱-同位素比值质谱法（GC-IRMS）和气相色谱-四极杆质谱法（GC-qMS）探索了四氯化碳（CCl 4）和三氯甲烷（CHCl 3）的化合物特异性氯同位素分析，其中GC-qMS在慕尼黑和纳沙泰尔之间的实验室间比较中使用相同类型的商业GC-qMS仪器进行了验证。GC-IRMS测量分析了CCl同位素体离子，而GC-qMS分别分析了同位素体离子CCl 3、CCl 2、CCl（CCl 4的）和CHCl 3、CHCl 2、CHCl（CHCl 3的）。最低量的依赖性（良好的线性），获得（i）在含H的碎片离子，其中35 Cl-至37 Cl-含离子的干扰被避免;（ii）与调谐参数有利于一个主要的，而不是多个碎片离子的质谱。优化的GC-qMS参数（停留时间70 ms，2种最丰富的离子）导致标准偏差为0.2‰（CHCl 3）和0.4‰（CCl 4），仅为GC-IRMS的0.1‰和0.2‰的两倍。为了比较两种方法和实验室的真实性，对四氯化碳和三氯甲烷降解实验的样品进行了分析，并根据四氯化碳和三氯甲烷的同位素不同的参考标准进行了校准（各两个）。极好的一致性证实，只要使用一组一致的同位素表征参比物质，两种方法均可获得真实结果。
Compound-specific chlorine isotope analysis of tetrachloromethane (CCl4) and trichloromethane (CHCl3) was explored by both, gas chromatography-isotope ratio mass spectrometry (GC-IRMS) and GC-quadrupole MS (GC-qMS), where GC-qMS was validated in an interlaboratory comparison between Munich and Neuchâtel with the same type of commercial GC-qMS instrument. GC-IRMS measurements analyzed CCl isotopologue ions, whereas GC-qMS analyzed the isotopologue ions CCl3, CCl2, CCl (of CCl4) and CHCl3, CHCl2, CHCl (of CHCl3), respectively. Lowest amount dependence (good linearity) was obtained (i) in H-containing fragment ions where interference of 35Cl- to 37Cl-containing ions was avoided; (ii) with tuning parameters favoring one predominant rather than multiple fragment ions in the mass spectra. Optimized GC-qMS parameters (dwell time 70 ms, 2 most abundant ions) resulted in standard deviations of 0.2‰ (CHCl3) and 0.4‰ (CCl4), which are only about twice as large as 0.1‰ and 0.2‰ for GC-IRMS. To compare also the trueness of both methods and laboratories, samples from CCl4 and CHCl3 degradation experiments were analyzed and calibrated against isotopically different reference standards for both CCl4 and CHCl3 (two of each). Excellent agreement confirms that true results can be obtained by both methods provided that a consistent set of isotopically characterized reference materials is used.