The
lipids of molluscs were removed from the extracts by gel permeation
chromatography using Bio-Beads S-X3 (200e400 mesh) and
evaporated to dryness to calculate the sample lipid content. The
fractions containing PCB were further purified by column chromatography
with activated silica gel (200 C for 24 h). Extracts were
concentrated to 1 mL and kept in vials at 20 C prior to gas
chromatography analysis.