Preparation Of Bi-functional Monomer Restricted Access Media-molecularly Imprinted Materials And Their Application In Complex Sample Pretreatment

With an increasing requirement for selective adsorption capacity,specific adsorption capacity,anti-disturbance performance and easy-to-use performance,monodisperse restricted access media bi-functional monomer molecularly imprinted polymers（RAM-MIPs）have become star products of pretreatment materials.It is widely used in the rapid pretreatments of target molecules in many complex samples.In order to further simplify the process of the pretreatment of complex samples,different fluoroquinolones were selected as target molecules（template molecules）to prepare RAM-MIPs which have specific adsorption capacity and macromolecular exclusion ability.In addition,in order to further broaden the types of molecular imprinting polymers,this article also prepares a molecularly imprinted polymer’s matrix（carrier）material to pave the molecularly imprinted polymer material towards anisotropic materials.The main work of this paper is as follows:1.Preparation of monodisperse restricted access media-molecularly imprinted polymers using bi-functional monomers for solid-phase extraction of sarafloxacin in complex samplesMonodisperse polystyrene(P_St)was used as the seed and monodisperse 4-vinylbenzyl chloride-divinylbenzene polymer(P_VBC/DVB)microspheres were synthesized by a one-step seed swelling polymerization method.Afterwards,the sarafloxacin（SAR）molecularly imprinted polymer（MIP）layer was prepared on the surface of P_VBC/DVBmicrospheres using SI-ATRP technology.Then,a restricted access media layer was prepared on the surface of MIP microspheres using SI-ATRP technology again.The equilibrium adsorption capacity of RAM-MIP microspheres for SAR was 149.17μmol·g^-1,the linear range was 4–300ng·g^-1;the limit of detection（LOD）of SAR was 1.27 ng·g^-1（signal-to-noise ratio（S/N）:3）,the limit of quantification was 4.23 ng·g^-1（signal-to-noise ratio（S/N）:10）,the recovery of SAR was 94.0%–101.3%,the intraday RSD was 1.1%–2.9%and the intraday RSD was1.5%–3.3%.The results show that this material has application value.2.Preparation of monodisperse restricted access media-molecularly imprinted polymers using bi-functional monomers for magnetic solid-phase extraction of pefloxacin in complex samplesThe solvothermal reduction method was used to prepare Fe₃O₄nanoparticles in the pores of sepiolite（SEPI）which was washed and sieved to obtain magnetic sepiolite microparticles（MSEPI）.Then silane coupling reagent（KH-550）and 2-bromoisobutyryl bromide were used to synthetic brominated MSEPI.Finally,a kind of restricted access-magnetic molecular imprinted polymers（MSEPI-RAM-MIPs）using organically MSEPI as a carrier was prepared by two consecutive SI-ATRP reactions.It was applied to the detection of pefloxacin（PFLX）in complex samples with high sugar content and rich protein.The adsorption capacity of MSEPI-RAM-MIPs for PFLX was 211.06 mg·g^-1,the recovery was 96.7%–103.4%,RSD was 2.6%–4.3%,and the LOD was 8.51 ng·g^-1（S/N=3）,the recovery was 89.7%–103.3%,the intraday RSD was 1.7%–3.2%and the intraday RSD was 1.3%–3.4%.3.Preparation of golf ball-shaped P_GMA-EGDMAmicrospheres which are used as molecularly imprinted material’s matrixPolyglycidyl methacrylate-ethylene glycol dimethacrylate(P_GMA-EGDMA)microspheres with a golf ball shape were prepared using"one-step seed swelling method".The morphology and composition of the P_GMA-EGDMAmicrospheres were successively characterized.And the reason for the directional differences of the P_GMA-EGDMAmicrospheres was speculated.Afterwards,the preparation of golf ball-shaped P_GMA-EGDMAmicrospheres was optimized.And the golf-shaped P_GMA-EGDMAmicrospheres with uniform particle size and uniform surface were obtained.The average particle size of the microspheres was 5.72μm and the main distribution range of the particle size was 80.95%–97.02%.