Preparation And Application Of Molecular Imprinted Materials Of Three Pesticides And Metabolites

China is a powerful agricultural producer.The use of pesticides is an important method to control diseases and insect pests of agricultural products in China.Therefore,the problem of pesticide residues is becoming more serious.We have continuously developed pesticide residue pretreatment technologies to deal with the problems of pesticide residue detection,such as supercritical fluid extraction technology,solid phase microextraction technology and microwave-assisted extraction technology.However,these sample pretreatment technologies have the disadvantages of wasting time,high cost and complicated process.It is of great significance to develop a pretreatment technology with strong selectivity,specificity and sensitivity.Molecular imprinting technology is just in line with this characteristic.Therefore,the molecular imprinting materials of three pesticides and metabolites are studied.1.Dinotefuran molecularly imprinted polymer was prepared with silica gel as carrier,methyl methacrylate as functional unit,azobisisobutyronitrile as modifier and tetraethoxysilane as crosslinking agent.The characterization was carried out by scanning electron microscope(SEM)and infrared spectroscopy(IR).The characteristics and binding properties of the recognition molecule of dinotefuran molecularly imprinted polymer to dinotefuran were studied by dynamic and selective experiments.The results showed that dinotefuran could be adsorbed well by dinotefuran molecularly imprinted polymer,the maximum adsorption capacity was 148.50 μg/mg,and the adsorption equilibrium reached about 90 min.Compared with the competitive molecule pymetrozine,the molecularly imprinted polymer of dinotefuran shows higher selective adsorption capacity for the template molecule dinotefuran,which has a good purification effect in the detection of pesticide residues.2.The indoxacarb molecular imprinted polymer was prepared.The properties of the indoxacarb molecularly imprinted polymer were determined through characterization and verification of adsorption properties.The results showed that the adsorption of the indoxacarb molecularly imprinted polymer reached saturation at the concentration of 50mg/L,and the adsorption capacity reached the maximum at 120 min with an adsorption capacity of 144.00 μg/mg,which has good adsorption performance.Compared with acetamiprid,it has selective adsorption and better purification effect than common purifying agent.3.Preparation of 6-chloronicotinic acid molecularly imprinted polymer,characterization and adsorption tests to verify the adsorption of 6-chloronicotinic acid molecularly imprinted polymer.The results showed that 6-chloronicotinic acid molecularly imprinted polymer had good adsorption capacity for 6-chloronicotinic acid.In different concentrations of 6-chloronicotinic acid standard solution,it was found that the adsorption capacity of the polymer reached saturation at 50 mg/L,and reached the maximum at 90 min at the same concentration,with the adsorption capacity of 132.00 μg/mg.Compared with PSA purifying agent material,the purifying effect is better,so 6-chloronicotinic acid molecularly imprinted polymer is more suitable for pesticide residue detection.