Surface Modification Of Silica And Magnetic Graphene In Application Of Separation And Enrichment

The surface modification plays an important role to broaden substrate's application scope.The traditional modification method of surface modification is bonding small molecules on its surface directly,the grafting ratio of the resulting materials is not satisfactory due to the limited binding sites,and thus the adsorbent has the poor adsorption property.In this study,we choose two kinds of substrates,silica and magnetic graphene,prepared two kinds of separation and adsorption materials via surface-initiated atom transfer radical polymerization(SI-ATRP)or dendritic polymerization method using POSS as a scaffold,the grafted rate of functional groups improved.The main content included:(1)A mixture of glycidyl methacrylate and 2-dimethylaminoethylmethacrylate,was grafted onto the surface of silica via a one-step surface-initiated atom transfer radical polymerization to prepare a novel hydrophilic interaction/anion-exchange mixed-mode chromatographic stationary phase.The grafted amounts of functional groups were controlled via varying the ratio of monomers in the polymerization system.The influences of water content,salt concentration and pH in the mobile phase were investigated to illustrate the mixed interaction between the stationary phase and analytes.The chromatographic characteristics of three kind of stationary phases were investigated by various solutes,especially acidic and basic solutes.The results indicated that the strategy proposed in this work was beneficial to develop various types of mixed-mode chromatographic stationary phases with adjustable selectivity to meet the needs of complex samples.Finally,the column was successfully employed in the isolation of melamine in liquid milk.(2)A high adsorption capacity boronate affinity adsorbent Fe3O4@GO@PDA@POSS@FPBA was synthesized by introducing polydopamine-coated magnetic graphene as base materials and anchoring POSS as a ligand,followed by reacting with 4-formylphenylboronic acid(FPBA).Detailed characterizations using fourier-transform infrared spectrometer(FTIR),scanning electron microscope(SEM)and superconducting quantum interference magnetometer(SQUID),proved that the boronate affinity adsorbent was prepared successfully.Several parameters,including adsorption time,pH value and elution solvent were optimized.The adsorbent saturated adsorption capacity for catechol,isoproterenol and salbutamol were 353,514,139 ?mol/g,which shows the potential to effectively analyze cis-diol substances in real samples.