Preparation And Application Of Molecularly Imprinted Polymers Of Patulin

Patulin?PAT?is a toxic mycotoxin produced by a variety of fungi.It is widely distributed in nature and mainly pollutes grains,fruits and their products.Therefore,it has received extensive attention from countries around the world.At present,the effective way to prevent and control mold pollution and ensure food safety is to establish a rapid and effective detection method and strengthen the detection and monitoring of patulin in agricultural products.Due to the complex sample matrix,the traditional extraction and enrichment method lacks selectivity,and the purification effect is not ideal.The matrix effect of impurities co-extraction often occurs,which affects the later instrument analysis results.Therefore,research and development of fast,efficient,selective,and high-throughput sample preparation techniques are of great significance for the detection of patulin in complex matrices.Combining molecular imprinting technology with magnetic nanotechnology and electrospinning technology can combine the advantages of molecularly imprinted polymers?MIPs?,magnetic nanomaterials and nanofiber membranes to achieve rapid separation and efficient enrichment of trace substances in complex samples.Based on the above research purpose and significance,MIPs,magnetic molecularly imprinted polymer?MMIPs?and molecularly imprinted nanofiber membranes?MINFMs?for patulin were successfully preparaed in this study.The details are as follows:1.Based on the virtual template molecular imprinting technology,we selected the structural analogs of patulin 2-oxin and 6-hydroxynicotinic acid?6-HNA?as virtual templates,and optimized the polymer preparation system.Finally,MIPs with specific adsorption of patulin was successfully polymerized by precipitation polymerization using 2-oxindole?2-oxin?and 6-hydroxynicotinic acid?6-HNA?as dual dummy templates.The molecularly imprinted solid phase extraction?MI-SPE?column was prepared by using the polymer as a sorbent.The research on the adsorption performance and adsorption mechanism of the polymer shows that the polymer has good specific adsorption to the target.At the same time,the conditions of the MI-SPE pretreatment program were optimized,and combined with LC-MS/MS,the MI-SPE-LC-MS/MS methods for patulin in 7 samples such as apple were established.The method was used to perform a three-level addition recovery test.The results showed that the mean recoveries were ranged between 79.4%and 97.9%with relative standard deviations?RSDs?less than 4.5%?n=3?at three spiking concentrations?2,10,and 50?g/L?.2.a novel magnetic molecularly imprinted polymer?MMIP?was prepared by surface imprinting technology using 2-oxin and 6-HNA as dual virtual templates,4-vinyl pyridine?4-VP?as the functional monomer and Fe₃O₄@SiO₂-CH=CH₂ as the carrier.By characterizing the adsorption capacity,crystal structure and magnetic strength of magnetic molecularly imprinted polymers?MMIPs?.The results showed that the molecularly imprinted polymer?MIP?was successfully coupled with magnetic nanoparticles and has superparamagnetism,which can be quickly separated from the solution by a magnetic field,and could be used as a magnetic selective recognition material.Moreover,The Q_maxax of the two binding sites of the MMIP were 9362.9?g/g and 127202.3?g/g,respectively.Shows that MMIPs have a greater adsorption capacity for patulin than conventional MIPs.Subsequently,the magnetic dispersion solid phase extraction procedure was optimized,and combined with LC-MS/MS,the detection of patulin in juice was achieved.At three spiking concentrations?1,10,and 50?g/L?,the mean recoveries were ranged between 79.4%and 97.9%with relative standard deviations?RSDs?less than 4.7%?n=3?.3.a novel organic-inorganic hybrid molecularly imprinted polymer with molecular recognition was synthesized by sol-gel molecular imprinting technique using 2-oxin and 6-HNA as dummy template molecules.Then,the molecularly imprinted polymer nanoparticles were coated with polyvinyl alcohol nanofibers by electrospinning to prepare a molecularly imprinted nanofiber membranes?MINFMs?with selective adsorption of patulin and 5-hydroxymethylfurfural?HMF?.The molecularly imprinted nanofiber membrane is used as an adsorption material based on membrane molecularly imprinted solid phase extraction for extracting patulin and HMF in apple juice.In the method evaluation,the mean recoveries of patulin were ranged between 102.2%-105.8%,the mean recoveries of5-hydroxymethylfurfural were ranged between 98.4%-106.8%,the relative standard deviations?RSDs?less than 3.3%and 6.3%,respectively.The detection time was significantly shortened,and the simultaneous determination of these two substances is achieved.