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J Chromatogr A

Title:		Compound-specific carbon isotope analysis of volatile organic compounds in complex soil extracts using purge and trap concentration coupled to heart-cutting two-dimensional gas chromatography-isotope ratio mass spectrometry
Author(s):		Zimmermann J; Wanner P; Hunkeler D;
Address:		"Centre for Hydrogeology and Geothermics, University of Neuchatel, Rue Emile-Argand 11, Neuchatel 2000, Switzerland. Electronic address: jeremy.zimmermann@unine.ch. Department of Earth Sciences, University of Gothenburg, Guldhedsgatan 5a, Goteborg 41320, Sweden. Centre for Hydrogeology and Geothermics, University of Neuchatel, Rue Emile-Argand 11, Neuchatel 2000, Switzerland"
Journal Title:		J Chromatogr A
Year:		2021
Volume:		20210818
Issue:
Page Number:		462480 -
DOI:		10.1016/j.chroma.2021.462480
ISSN/ISBN:		1873-3778 (Electronic) 0021-9673 (Linking)
Abstract:		"Compound-specific carbon isotope analysis (CSIA) is a powerful tool to track the origin and fate of organic subsurface contaminants including petroleum and chlorinated hydrocarbons and is typically applied to water samples. However, soil can form a significant contaminant reservoir. In soil samples, it can be challenging to recover sufficient amounts of volatile organic compounds (VOC) to perform CSIA. Soil samples often contain complex contaminant mixtures and gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) is highly dependent on good chromatographic separation due to the conversion to a single analyte. To extend the applicability of CSIA to complex volatile organic compound mixtures in soil samples, and to recover sufficient amounts of target compounds for carbon CSIA, we compared two soil extraction solvents, tetraglyme (TGDE) and methanol, and developed a heart-cutting two-dimensional GC-GC-C-IRMS method. We used purge & trap concentration of solvent-water mixtures to increase the amount of analyte delivered to the column and thus lower method detection limits. We optimized purge & trap and chromatographic parameters for twelve target compounds, including one suffering from poor purge efficiency. By using a 30 m thick-film non-polar column in the first and a 15 m polar column in the second dimension, we achieved good chromatographic separation for the target compounds in difficult matrices and high accuracy (trueness and precision) for carbon isotopic analysis. Tetraglyme extraction was shown to offer advantages over methanol for purge & trap concentration, leading to lower target compound method detection limits for CSIA of soil samples. The applicability of the developed method was demonstrated for a case study on soil extracts from a former manufacturing facility. Our approach extends the applicability of CSIA to an important matrix that often controls the long-term fate of contaminants in the subsurface"
Keywords:		"Carbon Isotopes/analysis Gas Chromatography-Mass Spectrometry *Hydrocarbons, Chlorinated/analysis Soil *Volatile Organic Compounds/analysis Compound-specific carbon isotope analysis Heart-cutting two-dimensional gas chromatography Isotope ratio mass spect;"
Notes:		"MedlineZimmermann, Jeremy Wanner, Philipp Hunkeler, Daniel eng Netherlands 2021/09/04 J Chromatogr A. 2021 Oct 11; 1655:462480. doi: 10.1016/j.chroma.2021.462480. Epub 2021 Aug 18"