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

Abstract

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 dibenzo[a,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 naphtho[1,2-a]- and naphtho[1,2-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 dibenzo[a,l]pyrene (5.4–42.3%) to the total carcinogenic activity of a PAH profile will be discussed comprising 14 selected isomers (benzo[b]naphtho[2,1-d]thiophene; cyclopenta[cd]pyrene; benz[a]anthracene; chrysene/triphenylene; sum of benzo[b]-, benzo[k]-, and benzo[j]fluoranthene; benzo[a]pyrene; indeno[1,2,3-cd]pyrene; dibenz[a,h]anthracene; benzo[ghi]perylene; anthanthrene; dibenzo[a,l]pyrene determined in these matrices.

Keywords:

• dibenzo[a,l]pyrene
• environmental occurrence
• GC/MS analysis
• naphtho[1,2-a]pyrene
• naphtho[1,2-e]pyrene
• polycyclic aromatic hydrocarbons

Acknowledgments

This work was financially supported by the Deutsche Forschungsgemeinschaft (DFG, Ja 270/6-1).

Notes

^a Limit of detection (LOD) and limit of quantitation (LOQ) for DB[a,l]P is 0.034 and 0.592 μg/kg.

^b LOD and LOQ for N[a]P is 0.021 and 0.212 μg/kg.

^c LOD and LOQ for N[e]P is 0.012 and 0.066 μg/kg.

^a 2.1-BNT, benzo[b]naphtho[2,1-d]thiophene; Cyc, cyclopenta[cd]pyrene; B[a]A, benz[a]anthracene; Chr/Tri, chrysene/triphenylene; B[b+k+j]F, sum of benzo[b]-, benzo[k]-, and benzo[j]fluoranthene; B[a]P, benzo[a]pyrene; Inp, indeno[1,2,3-cd]pyrene; DB[a,h]A, dibenz[a,h]anthracene; B[ghi]P, benzo[ghi]perylene; Ant, anthanthrene; DB[a,l]P, dibenzo[a,l]pyrene.

^b Concentration given in ng/cigarette.

^c %, Percentage related to the total carcinogenicity of the sum of 14 PAHs obtained by multiplication of the relative concentration and the potency factor.

^d Concentration given in mg/kg.