DETERMINATION OF DIBENZO[A,L]PYRENE AND OTHER FJORD-REGION PAH ISOMERS WITH MW 302 IN ENVIRONMENTAL SAMPLES

Polycyclic aromatic hydrocarbons (PAHs) occur in the environment as complex mixtures including compounds with mutagenic and carcinogenic activity. The PAH profile routinely determined in environmental samples at present encompasses isomers with molecular weight (MW) not greater than 300. However, PAHs with MW >300 have been demonstrated for several matrices to contribute up to 50% of the total activity when tested for carcinogenicity in experimental animals. Recent studies indicate that among the dibenzopyrenes with MW 302 dibenzoa,l]pyrene, possessing a fjord region, is by far the most carcinogenic PAH hitherto identified. To further elucidate the environmental relevance of this compound we have applied the isotope dilution GC/MS technique as analytical procedure to determine this compound and the related fjord region PAH naphtho1,2-a]- and naphtho1,2-e]pyrene in various matrices. Identification was based on comparison of UV and mass spectra as well as retention times of authentic reference materials. Determination of these PAHs was achieved after clean-up by several chromatographic steps including fractionation on a modified TABA-silica gel column. Quantitative data for matrices such as two cigarette smoke condensates, motor vehicle exhaust condensate (Otto-type engines), and tar-cork are reported. Based on toxic equivalent factors the relative contribution of dibenzoa,l]pyrene (5.4–42.3%) to the total carcinogenic activity of a PAH profile will be discussed comprising 14 selected isomers (benzob]naphtho2,1-d]thiophene; cyclopentacd]pyrene; benza]anthracene; chrysene/triphenylene; sum of benzob]-, benzok]-, and benzoj]fluoranthene; benzoa]pyrene; indeno1,2,3-cd]pyrene; dibenza,h]anthracene; benzoghi]perylene; anthanthrene; dibenzoa,l]pyrene determined in these matrices.