Comparison of analytical methods for determination of volatile organic compounds in soils

Abstract

This study compares aqueous extraction headspace/gas chromatography and purge-and-trap gas chromatography/mass spectrometry (EPA SW-846, method 8240) for the determination of four volatile organic compounds (VOCs) in soil. Comparisons were performed on two fortified soils and two soils obtained from sites where hazardous waste had been spilled or disposed. In only two of the cases studied were significant differences consistently found; for the two most hydrophobic compounds in a high organic carbon soil and for TCE in a field-contaminated soil that had previously shown slow aqueous VOC desorption. The findings strongly suggest that aqueous extraction/headspace GC using a portable instrument can be used to screen soils on site for VOCs, providing rapid same-day results, that will consistently identify the presence of these analytes and provide quantitative results which are generally not significantly different from slower more expensive, laboratory-based purge-and-trap analysis. 29 refs., 3 figs., 7 tabs.