Preparation Of Magnetic Molecularly Imprinted Polymer Composite And Its Application In Detection Of Veterinary Drug Residuse In Food

Food safety issues caused by veterinary drug residues have been concerned by consumers,so it is particularly important to establish simple,efficient and low-cost residue detection methods.Due to the complexity of the food matrix,sample pretreatment technology has become an important step in the qualitative and quantitative analysis of trace residues.Molecularly imprinted polymers(MIPs)have been widely used in various fields because of their high selectivity,good stability and reusability to target pollutants.Traditional MIPs was displayed the shortcomings of imprinting site embedding and large mass transfer resistance.Therefore,various materials with excellent performance as the carrier of MIPs was introduced to accelerate the development of molecular imprinting technology(MIT)and improve the adsorption property of MIPs.To this work,base on surface molecular imprinting technology(SMIT)and magnetic porous composites,two types of magnetic MIPs were developed,which were estradiol core-shell magnetic mesoporous silicon molecularly imprinted polymer(Fe3O4@m Si O2@MIP)and magnetic MIPs based on metal organic frameworks-graphene oxide composites(MOF/MGO@MIP).The two magnetic MIPs were regarded as MISPE adsorbent and combined with high performance liquid chromatography(HPLC)for the analysis of veterinary drug residues in actual samples.The main contents are as follows:1.Introduction.This part briefly review the phenomenon,hazards,detection methods and common sample pretreatment techniques of veterinary drug residues in food samples.At the same time,the basic principles of MIT and several methods of preparing MIPs were described.In order to overcome the shortcomings of traditional MIPs,improve adsorption performance and expand the application of MIT in different fields.Here,molecular imprinted composite materials(such as magnetic nanoparticles,silica,carbon nanomaterials,graphene and metal organic Framework,etc.)and its application in actual samples were introduced in detail.Finally,molecularly imprinted composite materials were used as adsorbents for the analysis of veterinary drugs in food samples.2.Development and application of core-shell magnetic estradiol molecularly imprinted polymers based on mesoporous silica composites.Core-shell magnetic estradiol(E2)molecularly imprinted polymers(Fe3O4@m Si O2@MIP)based on magnetic mesoporous silicon material(Fe3O4@m Si O2)was synthesized using the SMIT.The surface morphology and functional groups of MOF/MGO@MIP were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD),Brunauer-Emmett-Teller(BET)experiment,hysteresis regression curve(VSM)and thermogravimetric analysis(TGA).The adsorption performance of Fe3O4@m Si O2@MIP was studied through adsorption kinetics,adsorption isotherms and selectivity experiments,and then its adsorption mechanism was investigated using various adsorption models.The adsorption results matched well with a quasi-second-order kinetic model and a Freundlich isotherm model,with the maximum adsorption capacity,equilibrium adsorption time and imprinting factor of 4.01 mg g-1,30 min and 2.36,respectively.Meanwhile,the Fe3O4@m Si O2@MIP displayed higher adsorption capacity than Fe3O4@m Si O2@NIP.Under the optimal extraction conditions,a method base on Fe3O4@m Si O2@MIP combined with HPLCUV(Fe3O4@m Si O2@MIP /HPLC-UV)was established to separate and detect trace E2 in eggs and milk sample.The satisfactory recoveries,good RSD,low LODs and enrichment factor were 86.66-101.17%,1.3-4.9%,0.21μg kg-1 and 36,respectively.In addition,the Fe3O4@m Si O2@MIP can be recycled 7 times,which has good practical applicability.3.Development and application of novel magnetic sulfonamides molecularly imprinted polymers based on metal-organic frameworks/graphene oxide composites.Novel magnetic sulfonamides(SAs)MIPs based on metal-organic frameworks/graphene oxide composites(MOF/MGO@MIP)were synthesized using the SMIT.The morphologies and surface groups of MOF/MGO@MIP was characterized using SEM,TEM,FT-IR,XRD,BET,VSM and TGA.The adsorption performance of MOF/MGO@MIP was studied via adsorption kinetics,adsorption isotherms and selectivity experiments,and then its adsorption mechanism was investigated using various adsorption models.The adsorption results matched well with a quasi-second-order kinetic model and a Langmuir isotherm model,with the maximum adsorption capacity,equilibrium adsorption time and imprinting factor of 42.65 mg g-1,120 min and 1.61,respectively.Meanwhile,the MOF/MGO@MIP with excellent recyclability displayed higher adsorption capacity than MOF/MGO@NIP.Under the optimal extraction conditions,a method base on MOF/MGO@MIP combined with HPLC-UV(MOF/MGO@MIP/HPLC-UV)was established to separate and detect trace SAs in honey and milk samples,achieving lower limits of detection(LOD,0.39-0.47 μg kg-1).The spiked recovery and RSD were 81.38-96.71% and 1.4-6.3%,respectively.These results indicate that MOF/MGO@MIP/HPLC-UV can be used for the separation and detection of SAs in complex samples.