A comparison of sampling and analysis methods for lowppbC levels of volatile organic compounds in ambient air
| Autor: | Jeffrey R. Adams, Karen D. Oliver, William A. McClenny, E. Hunter Daughtrey, Keith G. Kronmiller, William A. Lonneman |
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| Rok vydání: | 2001 |
| Předmět: |
Detection limit
Air Pollutants Ozone Chemistry Sample (material) Public Health Environmental and Occupational Health Sampling (statistics) General Medicine Management Monitoring Policy and Law Sensitivity and Specificity Gas Chromatography-Mass Spectrometry Mean difference Specimen Handling Ambient air chemistry.chemical_compound Oxidants Photochemical Environmental chemistry Calibration Sample collection Organic Chemicals Volatilization Analysis method Environmental Monitoring |
| Zdroj: | Journal of Environmental Monitoring. 3:166-174 |
| ISSN: | 1464-0333 1464-0325 |
| DOI: | 10.1039/b007158g |
| Popis: | A carefully designed study was conducted during the summer of 1998 to collect samples of ambient air by canisters and compare the analysis results to direct sorbent preconcentration results taken at the time of sample collection. Thirty-two 1 h sample sets were taken, each composed of a “near-real-time” sample analyzed by an autoGC-MS XonTech 930/Varian Saturn 2000 system, and Summa and Silco canisters. Hourly total non-methane organic carbon (TNMOC), ozone, and meteorological measurements were also made. Each canister was analyzed on the autoGC-MS system for a target list of 108 volatile organic compounds (VOCs) and on a manual cryosampling GC-FID system. Comparisons were made between the collection and analysis methods. Because of the low sample loading (150–250 ppbC TNMOC), these comparisons were a stringent test of sample collection and analysis capabilities. The following specific conclusions may be drawn from this study. Reasonable precision (within 15% mean difference of duplicate analyses from the same canister) can be obtained for analyses of target VOCs at low-ppbC concentrations. Relative accuracy between the GC-MS and GC-FID analysis methods is excellent, as demonstrated by comparisons of analyses of the same canisters, if measurements are sufficiently above the detection limits. This is especially significant as the GC-MS and GC-FID were independently calibrated. While statistically significant differences may be observed between the results from canister and near-real-time samples, the differences were generally small and there were clear correlations between the canister results and the near-real-time results. Canister cleanliness limits detection below the EPA Method TO-14 acceptance standard of 0.2 ppbv (0.2–2 ppbC for target analytes). |
| Databáze: | OpenAIRE |
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