Study On Residue Analysis And Removel Method Of Pesticides In Vegetables

The invention and application of pesticide greatly increase the output of crops production. With the excessive and fallacious use, the pesticide residues in food, however, cause a lot of ill-influence on human's health. In recent years, poisoning accidents caused by the pesticide residues in vegetables and fruits were reported frequently in the country, which seriously threaten the consumers' health. People have since been aware of pesticide residues in vegetables production. Undoubtedly it is of great importance and the foundation of controlling pesticide residues and assuring the food safety that a study on pesticide analysis method and removal of pesticides in vegetable is conducted. The main results are listed as follow:1. Distilling effect of acetonitrile, acetone and n-hexane distilling Dimethoate, Deltamethrin and Cypermethrin in vegetables was determined and compared. The results showed the average fortified recovery of n-hexane on Dimethoate in Chinese cabbage was 74.09%, which couldn't satisfy the request of pesticide residue determination. But acetonitrile and acetone were of excellent distilling effect on Dimethoate, Deltamethrin and Cypermethrin in Chinese cabbage. So acetonitrile and acetone couldn't be used to the pesticide residue determination of the three pesticides. Due to the price of acetonitrile higher than acetone, acetone was deemed to the best distilling solution.2. Three distilling methods, rubbing, surging and soakage were compared. The results showed that three methods were all effective. But on operation, rubbing was hard sledding, and soakage took time. The method of surging was a convenient, labor- and time-saving.3. Four depurating columns were used to clean up the Dimethoate, Deltamethrin and Cypermethrin in vegetables. By comparing the effect of depuration, Active carbon-neutroalumina was the most perfect depurating column. Its depurating time was 45 minutes the average fortified recovery reached 85.64%~93.68%, moreover, the pesticide apexes were clear-cut separated with the apexes of impurities.4. Determining the pesticide residues in vegetables with the method confirmed, Chromatogrames showed that the apexes of the three pesticides could be clear-cut separated with the apexes of impurities. The experiments of the fortified recoveries showed that the average fortified recoveries and coefficients of variation were all satisfied the request of pesticide residues analysis. The determination limits of Dimethoate, Deltamethrin and Cypermethrin respectively were 0.003mg/kg, 0.002mg/kg and0.002mg/kg. So sensitive degree, veracity and exact degree satisfied the pesticide residues determination.5. The vegetable samples with pesticides were laundered by scour cooling water, warm water and H2O2. The results showed that four methods were of some removed effects of pesticide residues. The ability order of scour removing the pesticide residues was scour > warm water > H2O2 > cooling water. In addition, Dimethoate in vegetable was removed easily, in the next place it was Cypermethrin, Deltamethrin in vegetables was clean up difficultly.6. After Dimethoate, Deltamethrin and Cypermethrin ejected on vegetables lh, Id, 2d, 3d, 4d, 5d, 6d, 7d, the vegetables were washed by scour 3. The results showed the removing ratios put up the similar trend. The trend was that with the extending of time, the removing ratios decline, and the velocity of decline became slow gradually.