A simplified procedure for the determination of organochlorine pesticides and polychlorobiphenyls in edible vegetable oils

A one-step extraction–purification multiresidue method for the determination of 14 organochlorine pesticides (OCPs) and 7 polychlorinated biphenyls (PCBs) in edible vegetable oils based on matrix solid-phase dispersion (MSPD) has been developed. The experimental parameters affecting the recoveries and the efficiency of the cleanup procedure were thoroughly evaluated. Under an optimised condition, 0.5 g of oil sample was blended with 3.5 g of sulfuric acid-impregnated silica and 0.8 g of silica gel was used as co-column absorbent. The PCBs and OCPs were eluted by 10 mL of n-hexane/dichloromethane (70:30, v/v) and determined by gas chromatography equipped with an electron capture detector (GC-ECD). Good recoveries were obtained in the range of 69.6–105.3% with relative standard deviations (RSD) values below 15% in most cases. The limits of detection (LOD), based on a signal-to-noise ratio (S/N) of 3, were in the range of 0.04–0.74 ng/g.