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(68-01) A rapid and sensitive method for sampling and determination of gas-phase PAH species. Kock, Hans*,1, Ebinghaus, Ralf1, Heisterkamp, Inga1, Rosenfeld, Henning1, 1 GKSS-Research Centre Geesthacht, Geesthacht, Germany ABSTRACT- Polyaromatic Hydrocarbons (PAH) are a large group of compounds of 2 or more fused aromatic rings made entirely from carbon and hydrogen. The physical and chemical properties of the individual compounds are strongly dependent on their molecular weight and structure. This results in compound specific partitioning patterns between the gaseous and the particulate phase in ambient air. The purpose of the present work was to develop a rapid and sensitive method for the simultaneous determination of the vapor-phase PAH species in ambient air. This new method combines adsorption and preconcentration of PAH on graphitized carbon black and their quantification by desorption with microwave energy and subsequent GC/MS detection. The microwave unit enables very fast heating of the adsorbents to sufficiently high temperatures (700-800 C).This desorption technique allows the direct sample transfer from the sampling trap to the GC column without cryogenic trapping. The absolute detection limits for Fluorene, Anthracene, Phenanthrene, Pyrene and Fluoranthene are in the range of 100 - 500 picograms. Data are presented from measurements which were conducted to establish the experimental conditions and the associated equipment for the validation of the method. A time series of PAH concentrations ranges from 0,5 to 7 ng/m3 and reflects background conditions. The monthly mean profile of the gaseous PAH at a typical suburban site (GKSS, Geesthacht) was relatively constant throughout three month. These findings support the validity of using one volatile PAH as an index substance for the concentration levels of the other vapor phase PAH in ambient air, at least in terms of orders of magnitude. Key words: gas-phase PAH |
