Determination Of Estrogens In Animal-derived Food By DSPE-LC-MS/MS And Degradation Of Diethylstilbestrol In Aqueous Solution Using US-Fenton

Environmental estrogens that enter the body can produce toxins in the environment simulation with estrogen. It is a new type of environmental pollutants which can affect the functions of the human and animal’s reproductive system, immune system and nervous system. It widely exists in the environment, entering into the body and accumulating through drinking water and the animal-derived food. Environmental estrogens have been a threat to human health in recent years. Therefore, it is significant to study on the establishment of estrogen detection methods and degradation methods in order to increase food safety and environmental protection.This thesis illustrated the method for detection the animal-derived food, such as estrone, estradiol, estriol and diethylstilbestrol. It also studied a degradation method of the ultrasonic-Fenton reagent degradation of diethylstilbestrol, based on the conditions of optimizing the degradation. The main study is giving as follows:①A method was developed for determining4estrogens in animal-derived food such as milk, yoghurt, dairy, chicken, chicken liver and beef by dispersive solid phase extraction (DSPE) as clean up step and liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) as detection step. Acetonitrile was added into sample to precipitate the protein and anhydrous MgSO4was used for the removal of residual water, and then sample was cleaned up by DSPE using primary secondary’amine (PSA) dipolar adsorbent. The estrogens were detected by LC-MS/MS. This method can be simple, quick and had low cost, high recovery. Under the optimized conditions, the limits of detection (S/N=3) ranged from0.66μg/L to8.26μg/L. The average recoveries of4estrogens from the samples at three spiked levels ranged from75.00%to109.33%with RSDs of0.24%-9.23%. The method can provide a reliable basis for detection estrogen hormone residues in milk, yoghurt, chicken, beef and other animal-derived food.②The degradation of diethylstilbestrol (DES) in aqueous solution by ultrasound (US)-Fenton reagent progress, determination by LC-MS/MS was studied. The effect of treating factors including the concentration of DES, the reaction time, the reaction temperature, the pH value in solution, the ultrasound power and Fenton reagent was investigated. In the optimal conditions with the reaction temperature of0℃, the pH of3.0, the ultrasound power of200W, the H2O2of8%and FeSO4·7H2O of 0.2g/L in Fenton reagent, the degradation rate of DES in aqueous solution can reach up to85%with the treatment time of50min. DES degradation in the range50～25μ0g/L follows first order kinetics.