Determination of Residues of 11 Organic Pollutants and Their Migration in Polyethylene Food Contact Materials by GC-MS

Residues of the 11 common organic pollutantsdi-n-butyl phthalate (DBP), diisobutyl phthalate (DIBP), bis(2-ethyl)hexyl phthalate (DEHP), 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 4-chloro-benzophenone, benzoin dimethyl ether, 2-chlorothioxanthone, 2,4-diethylthanthene-9-one, bisphenol A in polyethylene (PE) food contact materials and their migration in 4 food simulants were determined by GC-MS, and parameters of the extraction solvent, chromatographic column, split ratio were optimized. The food-grade PE packaging material samples were scrubbed with anhydrous ethanol and cut into pieces, and an aliquot (0.5 g) was taken to immerse with 2 mL of acetone. The mixture was extracted by ultrasound for 1 h, and passeds through a 0.22 μm organic filter membrane, and the filtrate was analyzed by GC-MS for determination of the residue of organic pollutants in the sample. Food-grade PE samples were immersed in water, 3% (volume fraction) acetic acid solution, 10% (volume fraction) ethanol solution and isooctane at 40℃ for 24 h, taken out to dry, and analyzed according to the above method for determining the residues of organic pollutants in the samples. The migration of organic pollutants in each food simulant was calculated by the difference of the determined values before and after soaking. With HP-5MS capillary chromatographic column as stationary phase, the organic pollutants were separated under temperature-programmed conditions, and detected by mass spectrometer equipped with electron impact ion source. It was shown that the mass concentration of each organic pollutant was linearly related to its corresponding peak area in the range of 0.05-1.00 mg·L^-1, and the detection limits (3S/N) were 0.05-0.15 mg·kg^-1. Test for the spiked recovery was carried out on negative food-grade PE samples at the three concentration levels, giving recoveries in the range of 74.0%-89.5%, and RSDs (n=6) of the determined values ranged from 2.1% to 8.7%. The proposed method was used for the analysis of 11 food-grade PE packaging material samples randomly purchased from the market. Bisphenol A and DBP were detected in 1 sample with the detection amount of 0.070, 0.065 mg·kg^-1, 4-chloro-benzophenone was detected in the other sample with the detection amount of 0.086 mg·kg^-1, and the migration of these two positive samples in the 4 food simulants was lower than the detection limit.