Title: | Quantification of volatile organics in soil aging experiments using fourier transform infrared spectroscopy |
Author(s): | Thompson CJ; Riley RG; Amonette JE; Gassman PL; |
Address: | "Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, USA. Chris.Thompson@pnl.gov" |
DOI: | 10.1366/000370206778062156 |
ISSN/ISBN: | 0003-7028 (Print) 0003-7028 (Linking) |
Abstract: | "On-line Fourier transform infrared (FT-IR) spectroscopy was applied to monitor the concentration of halogenated volatile organic compounds in a sample-preparation process that simulates long-term, slow accumulation of contaminants in soils (i.e., aging). Artificial aging is conducted by circulating a supercritical fluid solution containing the contaminant(s) of interest through a packed soil column. Mid-infrared spectra of several volatile halocarbons were measured in supercritical Xe and CO(2) to evaluate possible interferences from the strong absorption of CO(2). Although some of the C-X bands were partially masked in supercritical CO(2), all of the compounds studied had distinct spectral features in the region 1400-700 cm(-1) and could be monitored in either solvent. Quantitative measurements of halogenated volatile organics in supercritical CO(2) were demonstrated with CCl(4). Excellent results were obtained over the range 7-280 mM. Representative artificial aging experiments were conducted on two test soils using CCl(4) as the contaminant. On-line (FT-IR) estimates of the aged soil concentrations were 1.3-4.4 times higher than off-line concentrations obtained by gas chromatography/mass spectrometry. The discrepancies were primarily ascribed to post-aging losses that occurred during depressurization and subsequent sample handling. FT-IR spectroscopy is shown to be a powerful tool for monitoring soil loading behavior and for developing artificial aging protocols" |
Keywords: | "Carbon/*chemistry Carbon Dioxide Carbon Tetrachloride/chemistry Environmental Monitoring/*instrumentation/*methods Environmental Pollutants/chemistry Hydrocarbons, Halogenated/chemistry Linear Models Pressure *Soil Solvents Spectroscopy, Fourier Transform;" |
Notes: | "MedlineThompson, Christopher J Riley, Robert G Amonette, James E Gassman, Paul L eng 2006/08/24 Appl Spectrosc. 2006 Aug; 60(8):914-9. doi: 10.1366/000370206778062156" |