Study On Rapid Detection For Organophosphorus Pesticides Residues In Vegetables

In order to solve the problems in rapid detection technology for pesticide residues, three parts were studied in this paper.1. Comparing the sensitivity of three sources (Musca domestica, cyprinoids brain, fowl liver) acetylcholinesterase (AChE) to three organophosphorus pesticides (dichlorvos, trichlorfon, omethoate). It is found that for dichlorvos, the sensitivity from high to low are Musca domestica, cyprinoids brain, fowl liver; for trichlorfon, the highest sensitive AChE is from Musca domestica, AChE from cyprinoids brain and fowl liver enzyme are not sensitive; for omethoate, below 300μg·L^-1 concentration, the inhibition rate of three AChE are little difference, when the concentration greater than 300μg·L^-1, inhibition effect of AChE from Musca domestica is better than the rest two. Comprehensive consider the sensitivity of three AChE to three pesticides, from the Musca domestica is better in instruction organophosphate pesticide.2. Research the immobilization effects of AChE from Musca domestica on the three microvoid filter film (nylon, acetate and nitrate film). It is found that the immobilized results of AChE on nitrocellulose membrane is the best. AChE immobilized on nitrocellulose membrane were studied, the best immobilization conditions are that 10U of AChE, 5μL of 5% (volume fraction) glutaraldehyde, 30μL of 1% (mass fraction) bovine serum albumin (BAS), dubbed 200μL enzyme solution, 4℃immobilized 8h.3. The optimization of determination for organophosphate pesticide residues was studied. In promise of higher sensitivity, a new low cost reagent components, whose dosage of acetylcholinesterase (AChE), substrate and chromogenic reagent are 3/4, 3/4 and 1/2 that of original components respectively. F-test proved that there is no significant difference between adjusted and original components. The lower determination limit of adjusted components to three pesticides are that omethoate 0.37mg·L^-1, trichlorphon 0.09mg·L^-1, dichlorvos 0.035mg·L^-1, which is consistent with those of national standard rapid determination method.