The Research On High-throughput Detection Of Pesticide Residues In Fruits And Vegetables By QuEChERS Combined With GC-MS/MS And LC-MS/MS

Pesticides play an important role in increasing crop yields,but overuse of pesticides can cause excessive pesticide residue levels in agricultural products,which result in harm to food safety and human health.In recent years,in order to ensure consumer safety and prevent emergencies,the state has increased the monitoring of pesticide residues in fruits and vegetables.The ever-increasing number of test items and increasingly stringent requirements made the detection of pesticide residues face a severe challenge.In this thesis,QuEChERS pretreatment method was combined with gas chromatography-triple quadrupole tandem mass spectrometry and high-performance liquid chromatography-triple quadrupole tandem mass spectrometry to develop a rapid screening assay for multiple pesticide residues in vegetables and fruits.The main contents and research results are as follows:1.QuEChERS-gas chromatography-triple quadrupole tandem mass spectrometry was developed for the rapid determination of 42 pesticide residues in fruits and vegetables.In this experiment,the extraction scheme in QuEChERS method,and the dosage of mixed purification agent composed of N-propyl ethylenediamine(PSA),anhydrous magnesium sulfate(MgS04),octadecylsilane bonded silica gel(C18),and graphitized carbon black(GCB)were optimzed.After separation by HP-5MS UI capillary column,gas chromatography-tandem mass spectrometry was used for the detection of multi-reaction ion monitoring(MRM)and quantification with external standard method.The results showed that the linear relationship of 42 pesticides was good in the range of 5-400?g/L,and the correlation coefficient(r)was between 0.9771-0.9998.At the level of 0.01 mg/kg,0.02 mg/kg and 0.1 mg/kg,The average spiked recovery rate of the 12 kinds of vegetables,fruit representative matrix(cabbage,celery,tomato,eggplant,potato,turnip,kidney bean,Chinese chives,apple,green jujube,grapes,orange)was 50.9%-139.7%,and relative standard deviations(RSD)was 0.7%to 30.0%.The quantitative limit of 42 pesticides was uniformly set at 0.01 mg/kg.At the same time,the new method established is compared with the international method.The results show that the new method has better method specificity and correctness.The precision is slightly lower than the two comparison methods,but most of them meet the standard formulation.With precision requirements,this method is reliable,simple,and fast,and can achieve high-throughput detection of 42 pesticides in vegetables and fruits.2.QuEChERS-liquid chromatography-triple quadrupole tandem mass spectrometry was developed for rapid determination of 10 pesticide residues in vegetables and fruits.Based on the QuEChERS pretreatment conditions optimized by the first method,this experiment further optimizes the amount of scavenger graphitized carbon black(GCB).After separation by Agilent poroshell 120 EC-C18 column,liquid Chromatography-tandem mass spectrometry was used for the detection of multi-reaction ion monitoring(MRM)and quantification with external standard method.The results showed that the linear relationship of the 10 pesticides was good in the range of 5-300 ?g/L and the correlation coefficient(r)was between 0.9982 and 0.9996.Under the three levels of addition(0.01 mg/kg,0.02 mg/kg and 0.1 mg/kg),the average spiked recoveries of these 12 vegetable and fruit representative matrices(cabbage,celery,tomato,eggplant,potato,turnip,kidney bean,Chinese chives,apple,green jujube,grapes,orange)was 52.3 to 125.8%with RSD in the range of From 0.61%to 10.39%,the limit of quantification for 10 pesticides can be uniformly set at 0.01 mg/kg.At the same time,this experiment compared the new method established with the international common method,and found that the new method has better recovery and RSD.The method is reliable,simple and rapid,and can realize high-throughput detection of 10 pesticides in vegetables and fruits.3.The newly established two methods were applied to actual sample testing.A total of 142 batches of vegetables and fruits in the circulation area of a certain district in Hunan Province were tested.There were 82 batches and 40 batches of samples with pesticide residues detected.Amine phosphorus,dichlorvos,acephate,difenoconazole,carbendazim,etc.in the residual content of vegetables in the high,through the large quantities of vegetables,fruit samples were measured and confirmed that this method is simple,accurate and quantitative.This method is suitable for the analysis and testing of various types of vegetables and fruits.