Study On High Throughput Determination Of Pesticides Multi-residues In Fruits And Vegetables By GC And GC-MS/MS And Their Application

Pesticides play an important role in increasing crop yields,but the abuse of pesticides can lead to excessive pesticide residues,affecting food safety and endangering human health.As a large agricultural product country,China's demand for fruits and vegetables is very large.Therefore,the supervision of agricultural products is also increasing.The number of pesticide residue testing projects is increasing,the requirements for pesticide residues are becoming more and more demanding,and the testing techniques and testing intensity of pesticide residues are also facing major tests.This paper optimizes the pretreatment and instrumental analysis methods of organophosphorus pesticide residue gas chromatography and multi-pesticide residual gas chromatography-triple quadrupole tandem mass spectrometry,and applies the newly established detection method to a certain city in Guangdong Province.In the detection and investigation of pesticide residues in fruits and vegetables in the field of catering,it is expected to provide an important reference and basis for the safety supervision of agricultural products.The main research contents and results of this paper are as follows:1.A method for rapid detection of 50 organophosphorus pesticide residues in fruits and vegetables by double-column double-column gas chromatography was established.The experiment studied and optimized the extraction solvent,extraction method,purification method,column selection and chromatographic conditions,and explored the influence of the three sample matrices on the peak shape and signal intensity of the fruit and vegetable to establish the matrix matching standard method.Get more accurate analysis results.They were separated by DB-1701 and DB-5 capillary columns,and the two columns were qualitatively selected.The DB-1701 column was selected as the quantitative column and quantified by FPD detector.The results showed that the linear relationship of 50 organophosphorus pesticides in the range of 4~1000?g/L was good,and the correlation coefficient(r)was between 0.9981 and 0.9998.Under the three levels of 0.05mg/kg,0.1 mg/kg and 0.5 mg/kg,the average recoveries of the three kinds of vegetables,fruit and fruit samples were 77.6~116.0%,relative standard deviation(RSD).The range is 0.3~19.1%,and the detection limit is 0.01mg/kg~0.05mg/kg.Compared with China's standard methods,this method has better method performance indicators,more reliable,fast and simple,and can achieve high-throughput detection of 50 organophosphorus pesticides in vegetables and fruits.2.A modified QuEChERS pretreatment method combined with gas chromatography-triple quadrupole tandem mass spectrometry for the determination of 78 pesticide residues in fruits and vegetables was established.The experiment optimizes the selection and dosage of the commonly used matrix scavengers PAS,GCB,C18 and MgSO4 in the QuEChERS method,studies the effects of matrix effects on the peaks,response values and standard linearity,and establishes accurate quantification by matrix matching criteria.After the-PESTICIDE II capillary column was separated,it was detected by gas chromatography-tandem mass spectrometry in(SRM)mode and quantified by internal standard method.The results showed that the 78 pesticides had poor linearity except for paraoxon,imipenem and picophora,and the other 75 pesticides had a good linear relationship in the range of 5~200?g/L.The correlation coefficient(r)ranged from 0.992 to 0.9999.The limit of quantification of 78 pesticides was 0.01 mg/kg.At the three levels of 0.01mg/kg,0.1 mg/kg,and 0.5 mg/kg,the recovery rates of acephate,chlorothalonil,and omethoate were poor,and the recovery rates of the remaining 75 pesticide compounds were 60.0% ~ 121.3%,the relative standard deviation were 0.1% to 19.8%.Through comparison and analysis with the national standard method,the method is simpler,more qualitative and quantitative,and is suitable for high-throughput detection of organophosphorus pesticides in daily fruits and vegetables.3.Apply the newly established two methods to the actual sample testing,965 batches of vegetable samples,242 batches of fruit samples in the sales field of a certain city in Guangdong Province,and 265 batches of vegetable samples and 120 batches of fruits in the catering field.The sample is tested.Among them,7 batches of unqualified vegetable samples were detected in the sales field,and the qualified rate was 99.3% and 99.2%,respectively.One batch of unqualified vegetable samples was detected in the catering field,and the pass rate was 99.6%.Among the pesticides with higher residual amounts are: chlorpyrifos,acesulfame,omethoate,dimethoate,profenofos,triazophos,cypermethrin,procymidone,cyhalothrin,cypermethrin.Through the detection of pesticide residues in large quantities of fruit and vegetable samples,the feasibility of the method is proved,and the advantages of simple operation,qualitative and quantitative accuracy are applicable to the detection of pesticide residues in various vegetables and fruits.