SORPTION TUBES PACKED WITH POLYDIMETHYLSILOXANE - A NEW AND PROMISINGTECHNIQUE FOR THE PRECONCENTRATION OF VOLATILES AND SEMI-VOLATILES FROM AIR AND GASEOUS SAMPLES

This paper is concerned with the determination of volatile and semivol atile organic components in air and gaseous (headspace) samples, focus ing primarily on polar analytes, Samples were analyzed by preconcentra tion on different (ad)sorbents followed by thermal desorption and anal ysis by capillary gas chromatography, The performance of a cartridge f illed with 100% polydimethylsiloxane (PDMS) particles was compared to that of adsorbents like Tenax TA and Carbo-trap 300. Though the PDMS p hase is non-polar it showed adequate retention for both polar and non- polar components. The blank runs of the PDMS trap were significantly b etter than those of most adsorbents and did not deteriorate, as was th e case with ad the conventional adsorbents investigated. With respect to trapping efficiencies, the PDMS phase performed better for most of the analytes under investigation compared to the adsorbents. For a ran ge of analytes including triethylamine, butanone, diacetyl, nicotine, and acetic acid the PDMS phase performed exceptionally well whereas al l adsorbents showed unsatisfactory performance. The packed PDMS traps were employed for the determination of organic acids, PAH's and nitro- PAH's in air and for the analysis of the headspace of cacao and hop.