Establishment Of A Multi-residue Analysis Method For Organophosphorus Pesticides In Vegetables

With the improvement of people's living standard,people's awareness of food safety is also increasing.People are increasingly concerned about vegetable safety.Therefore,it is necessary to establish a variety of organophosphorus pesticide residues detection methods with simple sample pretreatment,short analysis time and accurate experimental results.In this thesis,24 kinds of organophosphorus pesticides in vegetables were studied and discussed by gas chromatography.According to the detection methods of organophosphorus pesticides,it has been suggested that an analytical method for the simultaneous detection of 24 organophosphorus pesticides in vegetables has higher practical value.This thesis mainly explored and discussed the instrument conditions and pretreatment methods,and finally determined the best pretreatment methods and instrument conditions.The main pretreatment method used in this thesis is dispersive solid phase extraction(SPE),by which it is purified by 200 mgPSA and 200mgC18 for simple vegetables such as Chinese cabbage,and complex vegetables such as Chinese chives and lettuce are purified by 200 mgPSA,200mgC18 and 50 mgCarb.The optimum conditions are as follows: the sampling amount is 1.0?L.The inlet temperature is 250?.The sampling mode is non-distributary injection.The temperature programmed column temperature box is used.The flow rate of gas chromatography column is 1.0mL/min.The temperature of the detector is 280?.The tail gas flow rate is 50mL/min.The method has the advantages of simple sample pretreatment,fast analysis and low detection limit.The experiments of the recovery rate and precision are carried out under the above conditions.The good recovery rate is obtained by adding the standard.The value is 80.25%~109.51%,and the precision experiment of the standard solution is 0.53%~9.96%.Based on the determination of precision,it can be seen that 24 kinds of organophosphorus pesticides have good separation and stable response values on gas chromatograph.In this thesis,the linear range of organophosphorus pesticides determined is 0.01?g/mL~2?g/mL,and the linear correlation ecoefficiency is 0.9961~ 0.9999,and the detection limit is 0.002mg/kg to 0.005mg/kg.There were no significant differences between the above method and national standard method,which was conducted in this thesis as well.