GC×GC—A New Analytical Tool For Environmental Forensics
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Comprehensive two-dimensional gas chromatography, GC x GC, is a new analytical tool with a tremendous capability to separate and identify. organic compounds in complex environmental samples. GC x GC uses two different chromatography columns coupled serially by a modulator to produce a volatility by polarity separation and distribute compound peaks across a two-dimensional retention time plane. The two-dimensional separation produces an order of magnitude more resolved peaks than traditional GC methods. The grouping or ordering of the peaks in the GC x GC chromatogram facilitates the identification of unknown compounds and the comparison of complex environmental samples. When a mass spectrometer detector is used, each resolved GC x GC peak yields a single-component interference-free mass spectrum that leads to accurate matching with mass spectral libraries. GC x GC examination of marine sediment extracts identified a wide variety of chemical contaminants including polychlorinated biphenyls, p-nonylphenol isomers, polycyclic aromatic hydrocarbons, benzotriazoles, and the alkane, cycloalkane, alkylbenzene, alkylnaphthalene, and biomarker fractions of petroleum. The two-dimensional GC x GC chromatogram image permits rapid screening of the sediment extracts for these and other unknown contaminants. (C) 2002 Academic Press. Published by Elsvier Science on behalf of AEHS.