Optimization-based Establishment Of The Methods For High-throughput Detection Of Pesticide Residues In Agricultural Products And Their Applications

In recent years,with increasing living standard and enhanced awareness about food safety and health,both domestic and foreign consumers have generally attached importance to agricultural products,especially pesticide residue in agricultural products,while the law on the quality and safety of agricultural products,newly revised by the state and officially enforced on January 1,2023,further improves the supervisory system and strengthens legal liabilities.In response to such situation,based on Gas Chromatography-Mass Spectrometry/Mass Spectrometry(GC-MS/MS)and Liquid Chromatography-Mass Spectrometry/Mass Spectrometry(LC-MS/MS)technologies and their application characteristics,this research is designed to establish the application methods for rapid qualitative and quantitative detection of multiple pesticide compounds in four common edible agricultural products including fruit,vegetable,cereal,meat and egg and apply these methods in practical risk monitoring,thus providing government departments for supervision and law enforcement with the theoretical support in administering the quality and safety of agricultural products.Min research results are shown below:1.The QuEChERS pretreatment technology,GC-MS/MS and LC-MS/MS instrument parameters were optimized to separately establish QuEChERS-LC-MS/MS method for detecting 37 kinds of pesticide residues in agricultural products including fruit,vegetable,cereal,meat and egg and QuEChERS-GC-MS/MS method for detection of 72 kinds of pesticide residues in agricultural products including fruit,vegetable,cereal,meat and egg.For all the standard substances of pesticides covered by both methods,correlation coefficient within the concentration range of 5～500ng/m L was larger than 0.99,and linear relation was good.With respect to four categories of edible agricultural products including fruit,vegetable,cereal,meat and egg,the recovery rate ranged from 60% to 120%,each category’s RSD was less than 15%,and quantification limit was between 0.002mg/kg and 0.005mg/kg.Comparison with standards proved that new methods were accurate and reliable.2.Detection and analysis were conducted in terms of 4,428 samples of edible agricultural products,including 1,278 vegetable samples,1,212 fruit samples,1,023 cereal samples and 915 meat and egg samples,in some area of R City during 2020-2022 period.The result indicated that the overall quality level of local agricultural products needed to be improved and there were many cases where agricultural products were unqualified.However,agricultural products exceeding permitted levels of pesticide residues decreased year by year from 2020 to 2022,such agricultural products accounted for 2.54% in 2020,while this figure declined to 1.97% and 1.37% in 2021 and 2022,respectively.A number of pesticides were detected in multiple agricultural products.In regard to the residues of 72 kinds of pesticides,the proportions of agricultural products among 4,428 samples of edible agricultural products are listed in descending order by the kind of detected pesticide residue as follows: 0 kind>1-3 kinds>3-5 kinds> more than 5 kinds,and the agricultural products containing 3 and more than 3 kinds of pesticide residues accounted for one fifth of total agricultural product samples,and agricultural products exceeding permitted levels of pesticide residues in the area were dominated by fruits and vegetables available in the market.3.Based on the detection result concerning pesticide residues in agricultural products and local conditions,three kinds of agricultural products – leek,pak choi and banana – which made up the largest proportions of the total in terms of exceeding permitted levels of pesticide residues and having pesticide residues detected were chosen for human health risk evaluation.In leek,chlorpyrifos was the pesticide with the highest average Estimated Daily Intake(ave EDI),and six kinds of pesticides detected most frequently are listed in descending order by ave EDI as follows: chlorpyrifos > procymidone >omethoate >imidacloprid > acetamiprid > thiamethoxam.Six kinds of pesticides are listed in descending order by maximum ave EDI as follows: procymidone > imidacloprid >chlorpyrifos > acetamiprid > thiamethoxam > omethoate.In pak choi,cypermethrin was the pesticide with the highest ave EDI,and five kinds of pesticides detected most frequently are listed in descending order by ave EDI as follows: cypermethrin > acetamiprid > chlorpyrifos >isocarbophos > omethoate.In banana,thiamethoxam was the pesticide with the highest ave EDI,and five kinds of pesticides detected most frequently are listed in descending order by ave EDI as follows: thiamethoxam > imidacloprid > fenbuconazole > pyraclostrobin >iprodione.THQ and HI in these three kinds of agricultural products were less than 1,neither one exceeded the human health risk value and the combined pollution value of human health,showing that multiple residues would not pose significant hazards to human health.However,a high proportion of agricultural products containing residues detected and that of agricultural products exceeding permitted levels of pesticide residues suggest that irrational use of pesticides still exists in production,while high THQ and HI in some agricultural products show that there are certain hidden risks,to which relevant supervisory departments need to pay attention.Overall,two methods,for high-throughput detection of pesticide residues in agricultural products,established by this research by optimizing QuEChERS pretreatment technology,LC-MS/MS and GC-MS/MS instrument parameters are precise,sensitive and efficient.The result of applying both methods in detecting risks in agricultural products in some area of R City during 2020-2022 period indicates that the proportion of agricultural products containing pesticide residues in the area is generally high,the area sees agricultural products exceeding permitted levels of pesticide residues,while high THQ and HI in highly risky agricultural products suggest that certain hidden risks occur and there is still room for increasing the overall quality level of agricultural products.