Abstract: A new method for simultaneous determination of the residues of 17 phthalate acid esters (PAEs) in vegetable oils by gas chromatography-electrostatic field orbitrap high resolution mass spectrometry (Orbitrap GC-MS) was developed. The oil samples were extracted by acetonitrile with a whirl instrument and the extracts were frozen at ?20 ℃ for 30 min, and then purified by dispersive solid phase extraction with ostade-cylsilane (C18) and primary secondary amine as sorbents (150 mg per 2.0 g of sample each). Accurate mass measurements of the target analytes in the full scan mode could eliminate matrix interference effectively. Four typical vegetable oils (soybean oil, peanut oil, olive oil and rapeseed oil) were evaluated by the developed method. Good linearity was observed for the 17 PAEs in the concentration range from 0.01 to 2.0 mg/L with correlation coefficients greater than 0.995 0. The limits of detection (LODs) were 0.005–0.010 mg/kg and the limits of quantification (LOQs) were 0.015–0.030 mg/kg. The average recoveries at spiked levels of 0.03, 0.20 and 0.50 mg/kg were in the range of 80.2%–109.5% in the four matrices, with relative standard deviations (RSDs) of 1.2%–9.8%. The contents of the 17 PAEs in 50 vegetable oil samples were determined by this method. The detection rates of diisobutyl phthalate (DIBP), dicyclohexyl phthalate (DCHP), dibutyl phthalate (DBP) and bis(2-ethylhexyl) phthalate (DEHP) were higher than those of the other compounds, and the detection rates in soybean oil and rapeseed oil were higher than those in the other samples. The method proved to be simple, sensitive and suitable for the rapid screening and confirmation of PAEs in vegetable oils.

Key words: gas chromatography-electrostatic field orbitrap high resolution mass spectrometry; dispersive solid phase extraction; phthalate eaters; vegetable oils