AN IMPROVED METHOD FOR THE RECOVERY OF PETROLEUM-HYDROCARBONS FROM FISH MUSCLE-TISSUE

A method based on fish muscle hydrolysis with NaOH followed by additio n of CaCl2, and steam distillation, with direct analysis of a dichloro methane extract of the distillate by capillary gas chromatography (GC) , was evaluated for the recovery of bioaccumulated water-soluble hydro carbons from high-fat salmon muscle with the objectives of combining s implicity and minimal contamination by other materials. The 17 hydroca rbons tested as model compounds were primarily aromatics in the benzen e-methylnaphthalene range, including several substituted benzenes and naphthalenes but as well included some shorter chain aliphatic compoun ds. The mixture is representative of the major hydrocarbons present in the muscle of salmon which have been exposed to the seawater-soluble fraction of crude oil. Recovery studies were conducted at three concen tration levels. The standard solutions were spiked into 20 g of homoge nized salmon fillets and the mixture hydrolysed in NaOH solution for 2 h in a stoppered distillation flask. This was followed by the additio n of CaCl2 in solution to reduce foaming and 2 mi of dichloromethane a s a co-distillation solvent. The mixture was then steam distilled with the dichloromethane recovered in the distillate as the hydrocarbon ca rrier. Such distillates contained negligible amounts of nonhydrocarbon material, and were therefore suitable for direct GC analysis without the need of any clean-up step. Recoveries for all hydrocarbons analyze d were high and reproducibility acceptable in the higher spiking level s. The major advantage of the method is a reduced background level of non-hydrocarbon volatiles from control salmon flesh. This increases th e sensitivity of determining bioaccumulated tainting hydrocarbons whil e maintaining the basic simplicity of steam distillation. Copyright (C ) 1996 Elsevier Science Ltd