Abstract: An analytical method for simultaneous determination of 16 phthalate esters (PAEs) s in vegetable oils by quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction combined with gas chromatography mass spectrometry (GC-MS) was established. Acetonitrile saturated with n-hexane was used as the extraction solvent and dehydrated with anhydrous magnesium sulfate. The extraction time, extraction solvent volume, and purifying agent type and dosage were optimized. The applicability of this analytical method was verified with corn oil, peanut oil and sunflower oil samples. Meanwhile, the matrix effect of PAEs detection in the three vegetable oils was also evaluated. The mass spectrometer was operated in the selected-ion monitoring (SIM) mode and the matrix-matched internal standard calibration method was used for quantification. Results showed that the best extraction efficiency was obtained after vortex oscillation for 2 min with 4 mL of the extraction solvent, and the best purification efficiency was achieved using 100 mg/mL octadecyl bonded silica gel (C18) and 50 mg/mL ethylenediamine-N-propylsilane (PSA). The calibration curves for all target analytes displayed good linear relationships over the concentration range of 5–500 μg/L, with correlations coefficients of more than 0.999 0. The limits of detection (LODs) and limits of quantitation (LOQs) were 0.002–0.03 mg/kg and 0.008–0.1 mg/kg respectively. The average recoveries of the 16 PAEs at three spiked levels (0.04, 0.2 and 0.4 mg/kg) from corn oil, peanut oil and sunflower oil ranged from 80.2% to 118.6%, with relative standard deviations (RSDs) of 0.2% to 9.8%. The 16 PAEs exhibited an enhanced matrix effect in the three oil matrices, with a percentage enhancement in the range of 11.0% to 158.9%. However, the matrix-matched curve was found to effectively eliminate the matrix effects. The method was efficient, simple rapid, and suitable for determining the residues of 16 PAEs in vegetable oils.

Key words: QuEChERS; phthalate esters; vegetable oil; gas chromatography-mass spectrometry; matrix effect