BY ALAN ROSSNER

NIOSH recently released a new method for sampling and analysis of volatile organic compounds using evacuated canisters. Samples are analyzed using a preconcentrator/gas chromatograph/mass spectrometer system. This method was validated for 17 VOCs: ethanol, acetone, 2-propanol, dichloromethane, hexane, trichloromethane, 2,3-butanedione, 2,3-pentanedione, 2,3-hexanedione, benzene, methyl methacrylate, toluene, ethylbenzene, m,p-xylene, o-xylene, α-pinene, and d-limonene.  Traditional occupational exposure monitoring for VOCs uses sorbent tubes to collect analytes from an air stream. Sorbent-based techniques require the user to have some prior knowledge of the target analytes, approximate concentrations, and environmental conditions to effectively sample exposures. Whole-air sampling into evacuated canisters requires no prior knowledge of air concentrations as breakthrough is not an issue. The technique does not require battery-operated sampling pumps. The working range of the method encompasses both part-per-billion and part-per-million analyte concentrations in mixed-exposure environments. Canisters coupled with capillary flow controllers make sampling easier for the field industrial hygienist because the flow controllers require no on-site pre- or post-calibration.  The new method, NMAM 3900, is available as a PDF. Alan Rossner is director of Environmental Health Science and Environmental Science and Policy undergraduate programs at Clarkson University in Potsdam, N.Y.