Study On The Detection Technology Of 29 Sulfonylureas Based On The Preparation Of Molecularly Imprinted Polymers

Sulfonylureas are a kind of herbicides with high efficiency,broad spectrum,low toxicity and high selectivity.They are widely used in the control of weeds in paddy fields,soybean fields and corn fields.However,their unreasonable use has also led to a series of pesticide residues,which is threatening people's lives and health.Therefore,the research of pretreatment technology with class specific selectivity is significant for the detection of sulfonylureas.Molecular imprinting technology combined with magnetic nanotechnology can realize the rapid separation and efficient enrichment of sulfonylureas in agricultural products.Therefore,this study researched the preparation of sulfonylureas pretreatment materials,as well as the application research in related pretreatment technology.The details are as follows:1.Based on the principle of molecular recognition,the preparation system of molecularly imprinted polymers was established according to the molecular structure and physicochemical properties of sulfonylureas.Finally,molecular imprinted polymers with similar specific adsorption to sulfonylureas were synthesized by using metsulfuron-methyl and chlorosulfuron as double template molecules,4-VP as functional monomer and DVB as crosslinking agent.The surface morphology of the polymer was characterized,and it was found that the polymer had a porous structure.The adsorption performance of the polymer was evaluated by adsorption test,and the results showed that the imprinted polymer had a good retention effect on the template molecule.The selective adsorption experiment showed that the imprinted polymer had class specific recognition for sulfonylureas.2.A molecularly imprinted solid phase extraction(MI-SPE)column with class specific adsorption for29 sulfonylureas was prepared,and the solid phase extraction(SPE)procedure was determined.Then a method for the determination of 29 sulfonylurea pesticides residues in corn,cucumber,pear and soybean oil by MI-SPE-LC-MS/MS was established.The extraction conditions of MI-SPE were determined by using the imprinted polymers as fillers.Combined with LC-MS/MS,the MI-SPE-LC-MS/MS methods in four kinds of matrix were established.The results showed that Within the range of 2 ?g/L-100 ?g/L,the tested analytes have achieved a good linear association with correlation coefficient(R2)> 0.999.Under different spiking levels,the recovery rates were ranged from74.8%-110.5%,and the relative standard deviation(RSDs)were < 5.3%.3.A novel magnetic molecularly imprinted polymer(MMIP)was prepared by surface imprinting technology using metsulfuron-methyl and chlorosulfuron as double template molecules and Fe3O4@Si O2-CH=CH2 as the carrier.The magnetic molecularly imprinted polymer(MMIP)was characterized by a series of characterization methods.The results show that the polymer can be successfully coupled with magnetic nanoparticles and has paramagnetism,which is a good magnetic selective recognition material.In addition,the maximum apparent adsorption capacity was 37.6 mg/g,which was significantly higher than that of ordinary molecularly imprinted polymers.The magnetic dispersion solid phase extraction(MDSPE)procedure was optimized,and 29 sulfonylurea herbicides in agricultural products were detected by LC-MS / MS.The results showed that under different spiking levels,the recovery rates were ranged from 77.1%-107.7%,and the relative standard deviation(RSDs)were ranged from 0.6%-4.1%.