Study On The Direct Elisa Of Detection For Organophosphorus Pesticide Residue

Pesticide residue is one of the important hazards to human health.Atpresent,organophosphorus pesticide is the most popular pesticide used in agriculture,occupying about 70％to the total used. So detection of organophosphorus pesticide is ofsignificance for food safety.Currently, gas chromatography (GC) or high performance liquid chromatography(HPLC) are two common approaches for detection of Organophosphorus pesticide residue,involved in long sample cleanup procedureand considered as relatively time-consuming,expensive and laborious. They are not feasible for detection of large numbers of samplesand fast detection at spot.Enzyme-linked immunosorbentassay (ELISA) is a rapid, sensitive and selectivedetection at trace levels. It depends on the high specificity reaction between antibody andantigen, with low cost, safety, easily-handling and reliability.Recently, there are manyreport about Enzyme-linked immunoassay (ELISA) detection of pesticide residue,mostlyindirect competitive Enzyme-linked immunoassay. So the study mainly applianced directcompetitive Enzyme-linked immunoassay to nicely, easily-handling and rapidly dectectthe aimed hapten with the reaction of antibody and antigen, high sensitivity.The paper selected Methanmidophos, Parathion and Methyl parathion as studyobject ,which are already forbidden to use. According to the molecular structure andbiology characteristic of pesticide, the hapten was synthesized, which then wasconjugated to bovine serum album and ovalbumin for prodcuing immunogen and coatingantigen.Rabbit were immunized with the hapten-BSA conjugates,and the polyclonal antibodyaginst the Methanmidophos ,Parathion and Methyl parathion titers were 1:4000,1:4500and 1:6000,respectively. It has relatively low cross-reactivity with other majororganophosphorus pesticide. By direct competitive ELISA, the optimum workingconcentration of coating antibodies and HRP-antigens are 1:2000,0.001mg/mL,1:3000,0.01mg/mL,1:2000,1mg/mL, respectively, the detection limits are 0.01μg/mL,1μg/mL和0.01μg/mL, respectively; the recovery of sample is≥96％; a good correlation isobserved between the ELISA and GC with R≥96％. The viation coefficient of amongbatches all lower than 15％and within a batch are all lower than 5％, showing the stabilityof the setted kits.