Measurement of ¹³C/¹²C of chloroacetic acids by gas chromatography/combustion/isotope ratio mass spectrometry

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• 作者：Wong ; Charles S. ; Muir ; Derek C.G. ; Mabury ; Scott A.
• 关键词：Chloroacetic acids ; Isotope ratio mass spectrometry ; Stable isotopes
• 刊名：Chemosphere
• 出版年：2003
• 期刊代码：15_00456535
• 类别：env
• 出版时间：February, 2003
• 卷：50
• 期：7
• 页码：903-909
• 文件大小：97.8 K

摘要

This paper describes a novel analytical methodology using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) to measure the ¹³C/¹²C ratios of chloroacetic acids (CAAs). CAAs are a major class of environmental pollutants that are widely distributed throughout the world, often at relatively high concentrations, and are of concern due to their toxic effects, particularly on plants. The ¹³C/¹²C of CAA reagents was measured by IRMS subsequent to offline combustion. Aqueous solutions of these CAAs were derivatized to the corresponding methyl chloroacetates (MCAAs) with acidic methanol with a known isotopic composition, extracted into pentane, and analyzed by GC/C/IRMS. Measured ¹³C/¹²C ratios of derivatized MCAAs were in agreement with calculated values within 1‰ for monochloroacetic acid and trichloroacetic acid and within 2‰ for dichloroacetic acid, suggesting that methylation and other analytical methodology steps do not isotopically fractionate derivatized MCAAs. ¹³C/¹²C ratios of reagent CAAs from different sources had varying isotopic signatures suggesting differences in source carbon and/or production methods. Our results underscore the potential of stable isotopes to serve as tracers of environmental sources of CAAs.