Determination of monocyclic and polycyclic aromatic hydrocarbons in fish tissue

An analytical method is presented in which fish tissue is analyzed for neutral monocyclic and polycyclic aromatic hydrocarbons (AHs) and aromatic sulfur heterocycles (ASHs) by capillary column gas chromatography (CGC) with photoionization detection. The sample enrichment procedure includes saponification with aqueous KOH, acidification of the digestates, and extraction of the aromatic compounds into cyclopentane-dichloromethane. Adsorption chromatography on tandem segments of potassium silicate and silica gel removes 99% of the coextracted lipid. Final enrichment by gel permeation chromatography eliminates residual biogenic material and potentially interfering alkanes. Relatively volatile monoaromatics are included among the analytes by virtue of the efficiency of the complementary enrichment steps, the use of small quantities of only low-boiling solvents, and the selectivity of the detector. Most targeted compounds (AHs ranging in size from C3-alkylbenzenes through benzo[g,h,l]perylene and ASHs within the same size range) can be determined in 5 g (wet weight) samples of fish tissue at concentrations as low as 20 ng/g. Comparisons are made of recoveries of selected AHs under ordinary and gold fluorescent lighting conditions.