Study On Determination Of Pesticide Residue In Vegetable And Fruit And Preparation Of QX-1

The use of pesticides provides unquestionable benefits in increasing agricultural production.However,it has the drawback of pesticide residues which remain in fruit and vegetables,constituting a potential risk to consumers.In this paper a review concerning the determination of pesticide residues in fruit and vegetables is presented.It is impossible to establish one method to applying for all of pesticides and samples,so different methods are introduced to analysis different categories of pesticides,according to different physico-chemical properties.12 Organochlorine pesticides are detected by GC-ECD and extracted with 50mL acetone and 100mL petroleum aether and clean-up with sulphuric acid .The capillary column was DB-1.The injector temperature and the detector temperature was set at 260℃ and 280℃,respectively .The experiments were carried on the column temperature program as followd:initial temperature was 150℃,rate of 10℃/min to 210℃(hold 10 min),rate of 20 ℃/min to 240℃(hold 5 min).The pesticide residues were calculated by external standard method.Recoveries of majority of pesticides from spiked samples at fortification levels of mg/kg ranged from 87.4 to 104.0 % ,mean recovery≥ 80%. Relative standard deviations ranged from 1.6 to 5.5%.4 Pyrethrines are detected by GC-ECD followed by extracted with petroleum aethe and clean-up with Florisil column chromatography. The capillary column was SE-54.The injector temperature and the detector temperature was set at 260℃ and 320℃,respectively.The experiments were carried on the column temperature program as followd:initial temperature was 140℃,rate of 20℃/min to 290℃(hold 20 min).The pesticide residues were calculated by external standard method.The recoveries of 4 pyrethroid ranged from 89.3 to 104.8% ,the average recoveries were ≥80%, Relative standard deviations were between 3.0 and 5.8%.Four-factor and three-level orthogonal tests were used to optimize the SFE conditions.The best supercritical fluid extraction condition was established as followed: pressure 15Mpa,temperature 70℃,extraction time 20min,flow-rate 30 kg/h.