Preliminary Study On Organophosphorus Pesticides Rapid Test Strip

Objective:Organphosphorus pesticides rapid test strip is studied, which based on enzyme inhibition by organic phosphorus pesticide. The method is established for routine pesticide residues testing for fruits, vegetables, and rapid detection of pesticide in the market, as well as in farm land. Good foundation is laid and theoretical basis is provided, for the further exploiture and utilization cholinesterase to detect OP pesticide. Methods: Ammonium sulfate precipitation, procainamide-ECH Sepharose 4B affinity chromatography were used to separate and purify cholinesterase. Chitosan membrane as a carrier, cholinesterase was immobilized by glutaraldehyde cross-linking. Immobilization factors was studied by orthogonal experiment, which were bovine serum albumin (Bovine serum albumin, BSA) percent content, glutaraldehyde (Glutaraldehyde, GA) concentration, interaction between BSA% and the GA concentration, and membrane materials used in immobilization. Sensitivity and diversity of cholinesterase test strip was analyzed. The market for sale dichlorvos EC was calibrated. Differences and sensitivity of test strip were analyzed. Results:affect of conditions on the immobilization:vector> glutaraldehyde>glutaraldehyde×BSA>BSAconcentration. From 5.3×10-3-5.3μg/L, enzyme inhibition rate and the concentration of dichlorvos follow the regression equation:y =12.799Ln(x)+72.384(R=0.9724). Its minimum detectable concentration was 0.17μg/L. Immobilized enzyme activity did not change within 15 days. Conclusions:Separation and purification cholinesterase conditions:extraction buffer was containing 0.5% TritonX-100, 20mmol/L (pH7.0) phosphate buffer, precipitation with 40% sulfate ammonium. Immobilization conditions:chitosan membrane carrier,0.01% glutaraldehyde,2% bovine serum albumin,0.05mol/L (pH6.0) PBS. Conditions of separation, purification cholinesterase was Studied, and factors of various immobilization was explored. Methods of separation, purification cholinesterase and enzyme strip preparation were established. The immobilization method was reproducible. Immobilized enzyme was stable.