Gas chromatographic method for trapping and detection of volatile organic compounds from human mouth air

The present investigation describes a convenient method for collection and analysis of volatile organic compounds from 25 ml mouth air samples. Tenax-GC trapping devices coated with Teflon are used to adsorb and concentrate volatile organic compounds in mouth air at -20 degrees C, which are then thermally desorbed at 140 degrees C. Gas chromatography (GC) analyses are performed using an aluminum column coated with Teflon and packed with 2% poly-MPE on 80/100 mesh Tenax-GC, and employing a flame ionization detector. This procedure allows for amplification of peak heights and detection of compounds that may otherwise escape direct analysis. Of the six prominent peaks detected, identification based on retention times indicates the presence of methanol, acetaldehyde, ethanol and acetone. Volatiles collected using this procedure can be maintained at -20 degrees C for up to 48 hours before analysis. The compact sample tubes allow the system to be easily portable, particularly suitable for sampling breath of persons with localized oral or systemic diseases at locations away from the laboratory. The superiority of this method is that relatively small samples are required for analysis, unlike previously published methods which are based on collection of large volumes of expired air in plastic bags.