Selective pressurized liquid extraction of polychlorinated biphenyls from fat-containing food and feed samples influence of cell dimensions, solvent type, temperature and flush volume

Sulphuric acid impregnated silica was used for the lipid free extraction of polychlorinated biphenyls from fat containing food and feed matrices using pressurized liquid extraction on a Dionex ASE300, with 34 mL cells. Data were compared to a previous publication where extractions had been performed on a Dionex ASE200, with 33 mL cells. Four different fat/fat retainer ratios (FFRs) were tested (0.100, 0.075, 0.050 and 0.025) at 50 and 100 degrees C using n-pentane, n-hexane or n-heptane as extraction solvent. The best results were obtained with a FFR of 0.025 when applying a temperature of 100 degrees C. Both n-pentane and n-heptane were capable of replacing n-hexane as extraction solvent. A flush volume of 60% was sufficient as suggested in US Environmental Protection Agency Method 3545. The applicability of the method was demonstrated for naturally contaminated fish meal as well as various spiked and certified materials.