A new method was developed to determine the migration of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) from food contact materials (FCMs) using ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). FCM samples were soaked in three food simulants of water, 10% (v/v) aqueous ethanol solution, and 4% (v/v) acetic acid solution for the migration test, and then the migration liquid was extracted and enriched using the IL-DLLME. The key parameters in terms of the type and volume of extractant, vortex time, NaCl concentration, and the speed and time of centrifugation were investigated. The analytes were separated on a Waters ACQUITY UPLC BEH Shield RP18 column (50 mm×2.1 mm, 1.7 μm), eluted by gradient with acetonitrile and water, and quantified by electrospray ionization mass spectrometry in negative mode using multiple reaction monitoring (MRM). The experimental results showed good linearities (r2>0.99) in their concentration ranges. The limits of detection (LODs) were 0.5 and 1 μg/L, and the limits of quantitation (LOQs) were 2 and 5 μg/L for PFOA and PFOS, respectively. The recoveries of PFOA and PFOS ranged from 86.4% to 116.9% at three spiked levels with the relative standard deviations (RSDs) between 4.3% and 14.4% (n=6). The proposed method was demonstrated as accurate, efficient, eco-friendly, and suitable for the determination of the migration of PFOA and PFOS from FCMs.
Keywords: dispersive liquid-liquid microextraction (DLLME); food contact materials (FCMs); food simulants; ionic liquid (IL); perfluorooctane sulfonic acid (PFOS); perfluorooctanoic acid (PFOA); ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).