BUILDUP OF ARTIFACTS ON ADSORBENTS DURING STORAGE AND ITS EFFECT ON PASSIVE SAMPLING AND GAS CHROMATOGRAPHY-FLAME IONIZATION DETECTION OF LOW CONCENTRATIONS OF VOLATILE ORGANIC-COMPOUNDS IN AIR

The levels of blank artifacts on four adsorbents commonly used for air sampling (Tenax-TA, Tenax-GR, Carbotrap and Chromosorb 106) were observed to increase during storage. This may determine the detection limits and hence their suitability for the passive sampling of volatile organic compounds in ambient air. Blank build-up on Chromosorb 106 was very high, and this material cannot be used for passive sampling in ambient air. The blank build-up on Carbotrap was also high, especially in the chromatographic range corresponding to hydrocarbons of less than or equal to C-5, but that on Tenax-TA and Tenax-GR was very low. Simultaneous sampling was carried out using different adsorbents, and for compounds that are the main artifacts on adsorbents (e.g., benzene on Tenax, benzene and toluene on Carbotrap) the results from Carbotrap are much higher than those from Tenax-TA and Tenax-GR, and the results from Tenax-TA and Tenax-GR also vary.