Organophosphorus hydrolase potentiometric detection of pesticide residues Biosensor
|School||Northwest University of Science and Technology|
|Course||Agricultural Products Processing and Storage|
|Keywords||Organophosphorus pesticides Pesticide Residues Enzyme immobilization Enzyme sensor Organophosphorus hydrolase|
Organophosphorus pesticides with high efficacy, easily degraded, broad-spectrum, etc., in the agricultural production has been widely used to promote the agricultural production, but because of its high toxicity and irrational use of residual pollution caused aroused attention. Detection of organophosphorus pesticide residues biosensor is currently studied and has great prospects for development of a technology. Enzyme sensor is one of them. This selection potentiometric biosensor for the study, discusses the enzyme immobilization, detection conditions are given enzyme sensor detection range, the establishment of pesticide residues detected potential method. The results were as follows: (1) is given by experiment enzyme immobilization carrier. 0.45μm pore carrier film is better than fixed 0.8μm; nitrocellulose membrane fixed better than cellulose acetate membrane. Determining 0.45μm nitrocellulose membrane immobilized carrier. (2) fixed by immersion method was significantly better than the titration method, fixed the longer the better fixed to determine the fixed conditions: the enzyme membrane immersed in enzyme solution at 4 ℃ refrigerator standing 24h. (3) Pure immobilized enzyme dilution effect than good; 10% bovine serum albumin concentration fixed better than 1% and 5%; 2.5% concentration of glutaraldehyde fixed better than 5% and 1%; three The best preparation substance ratio of 13:13:1. (4) buffer concentration and pH affect the sensor's detection performance, test buffer solution to obtain the best 1mM, pH 8.0 in PBS buffer solution. (5) ΔpH increases with increasing temperature, obtained by experiment the optimum operating temperature range of the sensor is 45-50 ℃. (6) Preserved enzyme membrane is an important factor affecting the sensor repeatability, studies show that the immersion method can be well preserved in the enzyme, the buffer solution without loss of activity compared to the saved small, so the use of the enzyme PBS saved TESTED pieces for reuse. (7) enzyme sensor detection range of 0.005-0.1mg/cm3, the lowest detection limit was 0.001mg/cm3. (8) established the potential of pesticide residues detected a new method. In the detection of organophosphorus hydrolase enzyme, taking 130μl original enzyme solution, adding 130μl, 10% bovine serum albumin, and 10μl, 2.5% glutaraldehyde, by immersion method, allowed to stand at 4 ℃ 24h, fixed in place remove the reaction at 48 ℃ 5min, measuring reaction △ pH, concentration of pesticides on ΔpH plot to establish a standard curve, according to the working curve calculated concentration of pesticides.