本文建立了气相色谱-质谱串联（GC-MS）同步检测PET食品包装中6种小分子化合物的方法。对二氯甲烷超声波辅助提取法和苯酚/四氯乙烷混合溶液溶解法进行了对比和优化，萃取液经HP-5MS色谱柱分离，质谱检测器检测，标准品保留时间定性，峰面积定量。结果表明二氯甲烷超声辅助提取法在料液比（m:V）为1:15，萃取时长为30 min，次数为1次时萃取效果较好，6种小分子化合物在0.05~2 mg/L的浓度范围内呈良好线性，判定系数R2均大于0.9980，检出限为0.1~20 μg/L，定量限为1~25 μg/L，加标浓度为200、500、1000 μg/L的回收率为71.99%~109.99%，相对标准偏差（RSD）为0.01~8.20%，日内精密度均≤4.74%，日间精密度均≤5.86%。用该方法对市售的25种PET食品包装进行了检测，共有5个样品被检出目标物质甲苯、BHT或DEHP，最高含量分别为308.11 mg/kg、500.31 mg/kg和482.57 mg/kg。该方法前处理简便，分离度好，分析灵敏度高，适用于PET中6种小分子化合物的日常检测。

A method for determination of six small-molecule compounds in food packaging material polyethylene terephthalate (PET) was developed in this study, using gas chromatography coupled with mass spectrometry. Methylene chloride ultrasonic-assisted extraction and dissolution methods in a mixed solvent of phenol/1,1,2,2-tetrachloroethane were compared and optimized. The extract was separated using a HP-5MS column, the analytes were detected by mass spectrometer, and retention time and peak area were used for qualitative and quantitative analyses, respectively. The results showed that the optimum conditions for methylene chloride ultrasonic extraction were as follows: solid to liquid ratio (m:V) 1:15, extraction time 30 min, and extraction cycle one time. A good linearity was found for six small-molecule compounds in the range of 0.05~2 mg/L, with the coefficients of determination greater than 0.9980. The limit of detection and the limit of quantitation were 0.1~25 μg/L and 1~25 μg/L, respectively. The recovery rates of spike concentrations of 200, 500, and 1000 μg/L were between 71.99% and 109.99%, relative standard deviations (RSDs) were between 0.01~8.20%; the intra-day and inter-day precisions were less than 4.74% and 5.86%, respectively. This method was used for the determination of six small-molecule compounds in 25 different types of commercial PET materials used for food packaging. Toluene, butylated hydroxy toluene (BHT), or di-(2-ethylhexyl) phthalate (DEHP) were detected in five samples, and the highest contents of toluene, BHT, and DEHP found, were 308.11 mg/kg, 500.31 mg/kg and 482.57 mg/kg, respectively. The advantages of this method include simple pre-treatment procedure, good separation, and high sensitivity, and this method can be used for routine determination of six small-molecule compounds found in PET materials.

国家自然科学基金资助项目（21277061）