Determination Of Four Benzoyl Urea Pesticide Residues In Edible Agricultural Products And Methods Bioavailability Research

Benzoyl urea pesticides are insect growth regulators with no systemic feature,good activity of killing lepidoptera pests,low price and other advantages.The have been widely used in agricultural production of China in recent 20 years and plays an important and positive role in promoting the quality of agricultural products in China.But due to the long valid period of remaining in plant food,in case of long-term human exposure to benzoyl urea pesticides,they may damage human health.Pesticide abuse frequently occurs in today’s society,America,EU and other western developed countries and organizations have much stricter limitations on pesticide residue,so the problem demanding prompt solution in current society is to develop an analytic method which can detect the residues of multiple benzoyl urea pesticides in plant food at the same time.Now,there are already standards and methods related to analysis of benzoyl urea pesticide residues at home and abroad,but most of them are applicable to all foods and have no distinctness or specificity because different tests are not done according to the characteristics and classes of foods.The inspection and detection methods for analysis of residues of four benzoyl urea pesticides such as diflubenzuron,chlorbenzuron,flufenoxuron,teflubenzuron in different plant food matrixes were studied deeply and in detail in this paper.Three methods of solid phase extraction – high performance liquid chromatography,accelerated solvent extraction – gas chromatographic method,Qu ECh ERS rapid extraction – liquid chromatogram – mass spectrometry.Quantification was done with external standard method.In seven plant foods such as leek,cabbage,cucumber,oyster mushroom,apple,tomato,rice.the adding standard concentrations were 0.01 mg/kg and0.25 mg/kg,the average recovery rates were 74% and 102%,RSDs were 1.2% and 11%,the correlation coefficients were all more than 0.996,and the linearity ranges were within0.01 μg/m L ～ 5.00 μg/m L.Through comparison between four methods,this paper selected and determined the most appropriate inspection and detection method for different plant foods from perspectives of MRI,matrix effect,time cost,safety,operational complexity,etc.,which would play an effective supervisory role for reducing the inspection and detection cost and guaranteeing the safety of edible agricultural products.At the same time,this paper simulated the SHIME model of human gastrointestinal digestion,and established a method for residue analysis of four benzoyl urea pesticides in simulated gastric and intestinal fluid.After warm bath in simulated gastrointestinal solution,the samples were centrifuged.The supernatant was extracted and purified by Qu ECh ERS method,and determined by liquid chromatography-mass spectrometry.At1.0mg/kg ～ 5.0 mg/kg,the average recoveries of benzoyl urea pesticides in cucumber and apple were 74.6% ～ 95.2%,and the relative standard deviations were 0.870% ～ 9.76%.Based on the normal physiological conditions of human body,the parameters of SHIME model for the determination of bioavailability of benzoyl pesticides in cucumber and apple were determined as follows: p H2.5 of simulated gastric juice,digestion time 2h;The p H6.5 of intestinal fluid was simulated and the digestion time was 4h.The effects of p H value and digestion time on bioavailability in vitro in SHIME model were clarified.The bioavailability of pesticide residues in raw vegetables and fruits fortified with different dietary ingredients was evaluated by referring to the percentage content of protein,dietary fiber and vegetable oil in the Dietary Nutrient Reference Intake Scale for Chinese Residents(2016 edition).The results showed that protein decreased the bioavailability of benzoyl pesticides in cucumber(10.2% ～ 33.2%)and apple(14.7% ～ 31.8%),except that protein increased the bioavailability of benzoyl pesticides in cucumber(11.4%).Dietary fiber decreased the bioavailability of benzoyl pesticides in apple(10.2% ～ 33.2%).Vegetable oil could reduce the bioavailability of four benzorea pesticides by 20.9% ～34.1%.