Abstract:  A capillary gas chromatographic method with flame ionization detector (GC-FID) for the detection of the fivephthalates (dimethyl pthalate (DMP), diethyl phthalate(DEP), di-n-butyl phthalate(DBP), di-n-octyl phthalate (DOP), and di (2-ethylhexyl ) phthalate (DEHP)) respectively in food-packaging bags and the packed food was developed. The food-packaging bags were extracted with ethanol by ultrasonic. The supernatant was dehydrated and filtrated through membrane with 0.45μm diameter. The filtrate was injected into the GC system for analysis. Retention times of the peaks could be used for qualitative analysis. External standard method was used for quantitative analysis. The recoveries of the five phthalates were between 71.5% and 125.5%. The relative standard deviations were between 1.6% and 3.2%. The detection limits of the method were: 0.18ng for DMP, 0.13ng for DEP, 0.13ng for DBP, 0.15ng for DOP and 0.14ng for DEHP, respectively. The method presents the advantages of high precision, high sensitivity, small sample size, and simple pretreatment. The method can be used to test the five phthalates respectively in food-packaging bags and the packed food.

Key words: capillary gas chromatography, phthalates, food-packaging bags, packed food