| Phthalates(PAEs) are a class of processing agents for improving the flexibility of plastic products which are widely used in our daily life, and the PAEs in the plastic products are probably released into the foods, especially to edible oil, which is harmful to human health. Thus the surveillance investigation of the PAEs residue in edible vegetable oil and study of their migration characteristics of PAEs from packing materials into edible vegetable oil are necessary. So that it is able to control qualities and safety of products of vegetable oil. In addition to provide scientific data for PAEs pollution in edible vegetable oil caused by packing materials, as well as to lay the foundation for quality assurance of vegetable oil.This thesis developed a fast, concise, highly sensitive pretreatment method with low blank value for PAEs in edible vegetable oil samples. Optimization of critical analysis conditions on GC-MS which is detected for PAEs has been carried out. PAEs pollution in edible vegetable oils from 15 licensed edible vegetable oil production companies in Zengcheng area was investigated, and migration characteristics of PAEs from packing materials of edible vegetable oil was studied. The main research contents and results are summarized as follow:1. Optimization of a detecting method for PAEs in vegetable oil by GC-MS. According to the distinctions of chromatography and mass spectrum characteristics, methods of extraction-separation and purification between different PAEs, the parameters including extraction method, purification method, flow rate, temperature programming and time of solvent delay were investigated for improving the detection conditions. The results indicated that 1.0 m L/min as the flow rate, 60℃ for the initial temperature of temperature programming and 6.5 min as the time of solvent delay,selective ion scan model is the bestconditions for detection, according to the grouping way of time gap between adjacent peaks as less than 0.3 min, peaks of PAEs are divided into 12 groups.2. Establishment of method for pretreatment of PAEs samples. By means of dissolution in acetonitrile saturated hexane, extraction by hexane saturated acetonitrile, and purification by distributed solid phase extraction, samples can be pretreated in a fast,concise, highly sensitive way with low blank value for instrumental analysis.3. Detection of authentic edible vegetable oil samples in Zengcheng area. Samples were chosen from 15 typical edible vegetable oil production companies of edible vegetable oil with food production license in Zengcheng area. Utilizing the above-mentioned optimized conditions for samples pretreatment and instrumental analysis, the results showed that DBP and DIBP have been detected with varying contents in all samples; and DEHP has been detected in two samples.4. Studies on migration characteristics of PAEs from packing materials into edible vegetable oil. Plastic containers for edible vegetable oil which have not been used were chosen from above-mentioned companies for the measurement of migration amount.Influences of diverse temperatures and storage times on migration amount of PAEs from packing materials were investigated, using isooctane as simulation of edible vegetable oils.The results showed that Dibuthyl phthalate(DBP) and Diisobutyl phthalate(DIBP) have been detected with varying contents in all of these plastic containers, and that even Bis(2-ethylhexyl) phthalate(DEHP) has been detected in two samples. The types of detected PAEs corresponded to that detected in the edible vegetable oils from plastic packing bottles. These data indicated that DIBP, DBP and DEHP probably migrate to edible vegetable oil from plastic packing bottles, but detected amount of PAEs has no obvious corresponding relationship with that from plastic container. |
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