Study On Detection And Control Technology Of Environmental Endocrine Disrupters In Raw Milk

EDCs have some characteristics such as refractory,easy enrichment,disrupting the organism endocrine system and so on,which received increasing concerns.Especially,the existence of hormonal substances which has been found in animal foods in the past few years aroused people’s attentions.Five typical EDCs including estrone,estradiol,estriol,diethylstilbestrol,and bisphenol A were selected as the target compounds.A solid phase extraction-high performance liquid chromatography-tandem mass spectrometry method for simultaneous determination of five kinds of EDCs in raw milk was established.The EDCs were extracted by acetonitrile and analyzed by solid phase extraction and liquid chromatography-mass spectrometric.Results showed that:a good linear range from 5μg/L～200μg/L with correlation coefficient of above 0.9989 was obtained.The extraction recovery were 68.5%-105.6%and the relative standard deviation were 2.56%～7.59%.The limit of detection was 0.22μg/L～0.56μg/L(S/N=3).The established method was simple,sensitive and accurate,and reduced the use of derivative reagents,which was suitable for the detection of environmental estrogen residues in large quantities of raw milk.In this work,it is studied that how the EDCs changed in the raw milk after cows were injected aphrodisiac.At the first day,the concertration of three hormones(estrone,estradiol and estriol)rapidly increased,their contents were 0.29mg/L,0.26mg/L and 0.43mg/L.However,the contents have dropped below the detection limits in raw milk at the following six days.This indicated that metabolic process of cows was fast,and it was no problem if the raw milk was not solded on market after the cow injected drugs in six days.This paper traced the possible sources of EDCs in raw milk and detected the EDCs in the micro-environment on dairy farms including soil,water and cow feed.The method for soil sample treatment was purification method of raw milk plus a nitrogen blowing step,the same as feed sample treatment.The water sample treatment was simple,it was extracted by a C18-SPE column and methanol,and detected by LC-MS/MS analysis.Result showed that this method was suitable for detection of EDCs in water samples,which was fast,low detection limit,simple and practical.The actual detection of the eleven different dairy farms micro-environment at Beijing using above method.The results showed that the micro-environment of the different farms containing different amounts of EDCs.This study intended to use the sand type bedrid soil replaced the agricultural bedrid soil made of cow dung and concentrated feed exchanged compound feed,etc.According to our study,it was useful for detecting EDCs and tracing the possible sources in raw milk.Then there were some improved advices about the farms micro-environment would be proposed,which could reduce the possible causes.This study did some the foundation work for the detection of EDCs in raw milk.