A method for carbon stable isotope analysis of methyl halides and chlorofluorocarbons at pptv concentrations
A method for carbon stable isotope analysis of methyl halides and chlorofluorocarbons at pptv concentrations
复制标题
DOI：
10.1002/rcm.1791
复制
发表时间：
2005-01-01
影响因子：
2
通讯作者：
Kalin, RM
中科院分区：
文献类型：
--
作者：
Archbold, ME;Redeker, KR;Kalin, RM
预浓缩系统已经过验证，可与气相色谱/质谱/同位素比质谱仪（GC/MS/IRMS）配合使用，以确定环境空气中卤代甲烷（MeCl和MeBr）和氯氟烃（CFCs）的C-13/C-12比率。特定化合物的同位素组成可以提供关于其大气收支和地球化学的有用信息，而这些信息不能仅从丰度测量中确定。虽然预浓缩系统以前曾与GC/MS/IRMS一起用于大气痕量气体分析，但这是第一次报告系统验证测试的研究。验证结果表明，预浓缩系统和随后的分离技术不会显著改变目标卤代甲烷、CFC-12（CCl 2F 2）和CFC-113（C2Cl 3F 3）的稳定同位素比率。CFC-11（CCl 3 F）系统内确实发生了-27.5ppm至-25.6ppm的显着但一致的同位素变化，尽管该变化是可以纠正的。所提出的方法有能力从环境空气样品中的50多种其他化合物中分离出这些目标卤烃。分离允许在环境空气中测定大体积样品（！）的这六种目标痕量大气成分中的五种的稳定碳同位素比。10 L）。还介绍了贝尔法斯特市的代表性城市空气分析，其碳同位素结果与公布的MeCl（-39.1ppm）和CFC-113（-28.1ppm）的C-13/C-12分析值相似。然而，这是第一篇报告CFC-11（-29.4ppm）和CFC-12（-37.0ppm）的稳定碳同位素特征的论文。版权所有（C）2005约翰威利父子有限公司。
A pre-concentration system has been validated for use with a gas chromatography/mass spectrometry/isotope ratio mass spectrometer (GC/MS/IRMS) to determine ambient air C-13/C-12 ratios for methyl halides (MeCl and MeBr) and chlorofluorocarbons (CFCs). The isotopic composition of specific compounds can provide useful information on their atmospheric budgets and biogeochemistry that cannot be ascertained from abundance measurements alone. Although pre-concentration systems have been previously used with a GC/MS/IRMS for atmospheric trace gas analysis, this is the first study also to report system validation tests. Validation results indicate that the preconcentration system and subsequent separation technologies do not significantly alter the stable isotopic ratios of the target methyl halides, CFC-12 (CCl2F2) and CFC-113 (C2Cl3F3). Significant, but consistent, isotopic shifts of -27.5parts per thousand to -25.6parts per thousand do occur within the system for CFC-11 (CCl3F), although the shift is correctible. The method presented has the capacity to separate these target halocarbons from more than 50 other compounds in ambient air samples. Separation allows for the determination of stable carbon isotope ratios of five of these six target trace atmospheric constituents within ambient air for large volume samples (! 10 L). Representative urban air analyses from Belfast City are also presented which give carbon isotope results similar to published values for C-13/C-12 analysis of MeCl (-39.1parts per thousand) and CFC-113 (-28.1parts per thousand). However, this is the first paper reporting stable carbon isotope signatures for CFC-11 (-29.4parts per thousand) and CFC-12 (-37.0parts per thousand). Copyright (C) 2005 John Wiley Sons, Ltd.