Determination of 18 Polycyclic Aromatic Hydrocarbons in Edible Oils by Isotope Dilution GC-MS/MS

A method for the determination of 18 PAHs in edible oils was developed by ID-GC-MS/MS. The oil samples were mixed with cyclohexane in the ratio of 1∶1 (V/V) and then cleaned up by molecularly imprinted solid-phase extraction (SPE) catridge coupled to graphitized carbon blacks solid-phase extraction cartridge. Identification and quantification were performed using GC-MS/MS in MRM mode. In the method, the pre-treatment and GC-MS/MS conditions were optimized, such as the selection of SPE columns, clean-up conditions on the tandem columns, the temperature of the ion source. The method shows satisfactory linearity (R²>0.999) over the range assayed (1-200 μg/kg), and the LODs range from 0.03 to 0.27 μg/kg, and the LOQs range from 0.10 to 0.89 μg/kg. The pre-treatment recoveries using this method at three spiked concentration levels (5, 10, 50 μg/kg) range from 67.9% to 100.8%. The RSD is in the range of 0.5%-8.7%. The proposed analytical method has been successfully applied for the analysis of 18 PAHs in edible oils obtained from Beijing market. The results indicate that all the detected edible oil samples meet the requirement of China and EU regulation. This indicates that the developed method is suitable for the simultaneous determination and valued of 18 PAHs in edible oils.