Determination Of Phthaiate Esters In Edible Oil And Research On Its Kinetic Migration

Phthalate esters (PAEs) are the culprit of food plasticizer storm in recent years andbelong to environmental endocrine disruptors.The national relevant agencies treated the foodof PAEs issues seriously,edible oils were also included in the key monitoring food by theMinistry of Health.Due to the complexity of oil samples, in the GB/T21911-2008,the methoddetection limits were higher,low contents PAEs cannot be detected.In order to make a betterunderstanding of PAEs pollution levels in the edible oil,establishing a high sensitivity andlow method detection limits were necessary.In this paper,Five kinds of phthalateesters,DEP,DIBP,DBP,BBP and DEHP,that have adverse effects on human health werechosen for instrumental analysis,carried out the researching of determination,removing,migration,the specific research results are as follows:The analysis method of liquid-liquid extraction/phase extraction coupled enrichmentsand GC-MS is established to mensurate the five kinds of PAEs in edible oil.The samples wereextracted with acetonitrile and then frozen to remove oil and fat and cleaned up with a glassProElut PSA SPE column.The identification and quantification were performed by GC-MS infull ion scanning and selected ion monitoring (SIM) mode respectively.The limits ofinstrument detection of phthalate esters ranged from0.3μg/L to2.0μg/L (S/N=3),while thelimit of the method detection ranged from5.0μg/kg~30.0μg/kg.The average recoveries offive analytes spiked in oil matrices ranged from76.17%to98.81%with the relative standarddeviations of1.01%~7.20%.This method for the determination of five phthalate esters inedible oils has high accuracy and sensivity. In addition, the relative deviation of this methoddetection values compared with national standard method and the third party values were1.65%~31.28%,0.41%~31.28%respectively.The analysis method of gel permeation chromatography (GPC) with tandem massspectrometry is also established to mensurate the five kinds of PAEs in edibleoil.First,dissolving the edible oil with cyclohexane-ethyl acetate,then using GPC separatingand purifying.Finally,using tandem mass spectrometer to analyze result and quantified byexternal standards.The instrumental detection limits are less than1.0μg/L and the methoddetection limits are less than50.0μg/kg.In the three spiked levels of100μg/kg,1000μg/kgand5000μg/kg,recovery rates of the five kinds of PAEs are between80.52%and98.30%,andtheir relative standard deviation (RSD) are between0.39%and7.62%.According to different brands and types,edible oils sold on the market in China wereclassified,then the determination five kinds of common phthalate esters were investigated.The identified of BBP,DEP,DBP,DIBP and DEHP were7%,46%,89%,91%,100%,respectively.This showed that DIBP,DBP and DEHP were the most common three kinds of phthalate esters in all groups.The contents of DBP and DEHP in most edible oil were below the limitannounced by the Health Department,only9%edible oils the DBP and DEHP wereexcessive.The highest DBP was576.90μg/kg,about1.9times more than HealthDepartment;The highest DEHP was1672.27μg/kg,about1.1times more than HealthDepartment.Overall,the plasticizer levels in edible oils were lower and security in ourcountry.Based on market survey and enterprise reflection,the removing of DBP and DEHP in thetea seed oils which had higher DBP and DEHP were exploring through molecular distillationmethod.Under experimental conditions,the removing rate of DBP and DEHP were84.48%,93.57%respectively. In the spiked levels of2000μg/kg,the removing rate of DBP and DEHPwere91.70%,93.11%respectively.With the experimental conditions,the removing of DBPand DEHP by molecular distillation was good.DBP and DEHP migration kinetics from the plastic to the soybean oil and rapeseed oilwere studied, experiments are conducted under different temperature and the levels of DBPand DEHP were measured on a regular basis. Using the experiment datas,migration patternswere established in Matlab based on the Second Fick’s law,and then calculated diffusioncoefficient D and partition coefficient KP/F.For example,in the rapeed oil at roomtemperature,37,℃50℃DBP diffusion coefficients(D) were5.620×10-11cm2/s,1.426×10-10cm2/s,5.760×10-10cm2/s respectively,while partition coefficient(KP/F) were74.22,70.01,42.52respectively.DEHP diffusion coefficients were1.250×10-11cm2/s、3.880×10-11cm2/s、7.680×10-11cm2/s respectively,KP/Fwere162.44、138.87、105.79.Follow the rules that withthe temperature rise the D were greater partition,KP/Fvalues were smaller.DBP was morelikely to migrate in the same edible oil as DBP molecular weight smaller than DEHP.Inaddition,the calculated migration levels are compared with the experimental migration levelsby RMSE which was between0.877%~6.220%,showing good agreement was found betweenthe experimental and the estimated data allowing validation of this model for predictingdiffusion processes in edible oil.