Research Of Detection Methods For Common Pesticide Residues In Vegetables And Fruits

For a long time,the use of pesticides has played a great role in the increasing production of agricultural products to a certain extent.However,the use of pesticides is also a "double-edged sword".Long-term exposure to pesticides in agricultural production and pesticide residues in fruits,vegetables,grain,oil and tea can directly endanger the health of people.Pesticide residues is a global food safety problem,and many countries and international organizations have formulated very strict limit standards.In recent years,the food safety situation in China has been paid more and more attention by government supervision departments and consumers.It is of great practical significance to fully supervise the use of pesticides and accurately detect the residues for the construction of food safety management system.Due to some objective factors,the use of pesticides in some agricultural product industries is high in China.With the increasingly strict food safety policies in many countries in the world,there are more and more barriers for the export of some fruits and vegetables in China.It is extremely urgent to establish a rapid,simple and sensitive method for the detection of pesticide residues in fruits and vegetables,so as to improve food safety.This paper attempts to systematically study the detection methods in this field,and the main research contents are as follows:1.A method for the determination of 34 pesticide residues in 10 kinds of vegetables and fruits based on Qu ECh ERS-ultra performance liquid chromatography-tandem triple quadrupole mass spectrometer was established.The extraction method of Qu ECh ERS method and the dosage of anhydrous magnesium sulfate(Mg SO4),N-(n-Propyl)ethylenediamine(primary secondaryamine,PSA),graphitized carbon black(GCB)and octadecylsilane chemically bonded silica(C18)were optimized in this experiment.After separation by C18(Hypersil GOLDTM)liquid chromatography column,detection was carried out under ultra-high pressure liquid chromatography-triple quadrupole tandem mass spectrometry multi-reactive ion monitoring mode(multiple reaction monitoring,MRM)and quantitative analysis by external standard method.The results showed that 34 pesticides had good linearity in the range of 5~300 μg/L,and the correlation coefficient(R2)ranged from 0.9906 to 0.9996.The average recoveries of celery,eggplant,pepper,tomato,cucumber,cabbage,cowpea,leek,apple and peach were 60.2%~138.0% and the relative standard deviations(relative standard deviation,RSD)were 1.0%~15.4% at three levels of 0.01 mg/kg,0.02 mg/kg and 0.10 mg/kg,respectively.Compared with the national standard method,it is found that the optimized method has more accurate performance index.2.The method based on Qu ECh ERS-gas chromatography-tandem triple quadrupole mass spectrometer for the determination of 20 pesticide residues in 10 kinds of fruits and vegetables was established.According to the previous optimized Qu ECh ERS pretreatment method,this experiment further optimized the dosage of GCB to meet the requirements of GC-MS/MS instruments.With capillary column,gas chromatography-triple quadrupole tandem mass spectrometer was used for detection under the condition of multi-reactive ion monitoring mode(MRM),and external standard method was used for quantification.The results showed that 20 pesticides had good linearity in the range of 5~400 μg/L,and the correlation coefficient(R2)ranged from 0.9913 to 0.9997.The average recoveries of celery,eggplant,pepper,tomato,cucumber,cabbage,cowpea,leek,apple and peach were 59.2%~130.4% and the relative standard deviation(RSD)was 0.3%~15.0%.Meanwhile,the optimized pretreatment method was compared with the national recommendedstandard method,and the experimental results showed that the optimized new method had higher recovery rate and precision.3.After optimization,2 new methods were applied to the actual detection test.34 kinds of pesticide residues and 20 kinds of pesticide residues were detected in 500 batches of vegetables and fruits in circulation in a certain area of Shandong Province,and pesticides were detected in 144 batches of samples,among which carbendazim,acetamiprid,difenoconazole,thiamethoxam,imidacloprid and other pesticide residues were higher.The results of actual samples also confirmed that the new method is simple,accurate and accurate,which is suitable for rapid detection of pesticide residues in conventional vegetables and fruits.