采用气相色谱-质谱法(GC-MS)测定聚乙烯(PE)食品接触材料中11种常见有机污染物[邻苯二甲酸二正丁酯(DBP)、邻苯二甲酸二异丁酯(DIBP)、邻苯二甲酸二(2-乙基)己酯(DEHP)、2-甲基二苯甲酮、3-甲基二苯甲酮、4-甲基二苯甲酮、4-氯-二苯甲酮、安息香二甲醚、2-氯噻吨酮、2,4-二乙基硫杂蒽-9-酮、双酚A]的残留量以及其在4种食品模拟物中的迁移量,并对提取溶剂、色谱柱、分流比等条件进行优化。将食品级PE包装材料样品用无水乙醇擦洗干净后剪碎,分取0.5 g,加入2 mL丙酮浸没样品,超声提取1 h,过0.22 μm有机滤膜,用GC-MS测定样品中有机污染物的残留量。将食品级PE样品分别置于水、3%(体积分数)乙酸溶液、10%(体积分数)乙醇溶液和异辛烷中,于40℃浸泡24 h,取出晾干,按照上述测定样品中有机污染物残留量的方法分析,以浸泡前后测定值的差值计算各食品模拟物中有机污染物的迁移量。以HP-5MS毛细管色谱柱作为固定相在程序升温条件下分离各有机污染物,以配有电子轰击离子源的质谱仪检测。结果显示,各有机污染物的质量浓度均在0.05~1.00 mg·L^-1内与其对应的峰面积呈线性关系,检出限(3S/N)为0.05~0.15 mg·kg^-1;对阴性食品级PE样品进行3个浓度水平的加标回收试验,回收率为74.0%~89.5%,测定值的相对标准偏差(n=6)为2.1%~8.7%。方法用于从市面上随机购买的11个食品级PE包装材料样品的分析,仅在1个样品中检出了双酚A和DBP,检出量为0.070,0.065 mg·kg^-1,在另1个样品中检出了4-氯-二苯甲酮,检出量为0.086 mg·kg^-1,这两个阳性样品在4种食品模拟物中迁移量均低于检出限。

Residues of the 11 common organic pollutants[di-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.