The Determination And Migration Of Phthalate Ester In Plastic Bagged Milk

Milk is a necessary food that people absorb nourishment in daily life. Plastic baggedmilk is more populary because it is suitable for dringing. However, because the effects ofstorage temperaature and time, hamful substances in plastic bags such phthalate acid esters（PAEs）will migrate to milk and pollute milk. This paper optimize the pretreatment ofextraction of PAEs in milk, the resulting method was set up to determine the fourphthalates in plastic bagged milk. The migration of PAEs from plastic bagged to milk havebeen studied through the experiment conditions, such as storing temperature and storingtime. Based on the previous studies, this paper has completed the following research work:Part I Establishment of gas chromatography-mass spectrometry (GC-MS) methodFour phthalate esters (DEP、DPP、DBP、DiBP、DAP、DHP、BBP、DEHP) havebeen studied by gas chromatography, gas chromatography-mass, high performance liquidchromato graphy technology in this thesis. A simple and rapid method for the simultaneousdetermination of4phthalate acid esters（PAEs）migration in milk powder by gaschromatography-mass spectrometry（GC-MS）was developed.Part II Study on solid phase extraction conditionsA C18solid-phase extraction column was prepared to enrich and purify4PAEs ofmilk in plastic container, disscuss and analysis by gas chromatography-mass spectrometry(GC-MS). The optimum conditions of solid-phase extraction were as follows: the eluent isacetone, and the volume of elution is4mL. The rate of elution is0.5mL/min. The result arethat the linear range of4kinds of PAEs are0.5mg/L-8.0mg/L, correlation coefficients aregreater than0.99, the lowest detection limits between0.018mg/L-0.022mg/L, the recoveryrate is82.1%-126.4%, RSD (n=5) is less than5%.Part III A preliminary study on the migrate of PAEs in plastic bagged to milkSetting different storing temperature and storing time (3d,6d,9d,12d,15d,18d,21d,24d,27d,30d)detect the PAEs content of the milk. The result shows，the migration of4kinds of PAEs are different. The content frommost to least is DEHP、DBP、DMP、DEP.Within the quality guarantee period,the migration of4kinds of PAEs is increased gradually.The migration is increased significantly, after many days storage, migration quantity isincreasing yet, but more slowly. Compared with the milk which storage in refrigerator with4℃, in the normal storing temperature, the migration quantity of4kinds of PAEs is more.