Preparation And Application Of Regenerate Cellulose-based And Polydopamine Coated Magnetic Graphene-based High Capacity Boronate Affinity Materials

Solid phase extraction has very important applications in analytical chemistry.Membrane extraction and magnetic solid phase extraction has become important branches in solid phase extraction.Due to the fact that membrane extraction can facilitate extraction procedure,and has potential for automation and achieve on-line connection to instrument;Magnetic solid phase extraction has quick separation,easy to operate,good dispersibility,high extraction efficiency,etc,they have been widely applied for sample preconcentration and cleanup in analytical chemistry.Boronate affinity provides a way for specific recognition of cis-diol containing molecules,and has been broadly used recently.In this thesis,two kinds of boronate affinity materials based on regenerated cellulose membrane and polydopamine-coated magnetic graphene has been synthesized,and their adsorption properties to cis-diol containing molecules were investigated.The research content mainly includes:(1)The RC membranes were firstly epoxidized with epoxy chloropropane.Then,PEI was grafted onto the membrane surface through a ring-opening reaction of epoxy group with amine to introduce high density of amine groups.Finally,4-FPBA was immobilized onto the membrane via a Schiff-base reaction.Detailed characterizations using attenuated total reflection fourier-transform infrared spectrometer(ATR-FTIR),X-ray photoelectron spectroscopy(XPS),atomic force microscope(AFM)and water flux proved the successful preparation of the boronate affinity membranes.The boronate affinity membrane possessed high selectivity and high adsorption capacity to cis-diol containing molecules,its saturated static adsorption capacity for catechol,salbutamol,dopamine and adenosine were 511,103,472 and 120 ?mol/g respectively,and its dynamic adsorption capacity of dopamine was estimated to be 140 ?mol/g.In addition,the membrane showed very fast adsorption and desorption equilibration for the cis-diol containing molecules.The membrane was successfully applied in the enrichment of dopamine in urine samples,with very good reusability,indicating its promising applications in the pretreatment of real complex samples.(2)A high adsorption capacity boronate affinity adsorbent was prepared via surface initiated-atom transfer radical polymerization(SI-ATRP),based on polydopamine-coated magnetic graphene,which has the features of good hydrophilicity,high specific surface area and easy seperation.The adsorbent was characterized by Fourier-transform infrared spectrometer(FTIR),UV-Vis spectroscopy,transmission electron microscope(TEM),x-ray powder diffraction(XRD),the results indicated the successful preparation of adsorbent.The adsorbent saturated adsorption capacity for adenosine,salbutamol,catechol were 154,357,1111 ?mol/g,respectively.The prepared adsorbent has good adsorption toward cis-diol countaining molecules.To add 1 mol/L sodium chloride into the buffer can effectively promote the adsorption of adenosine and dopamine,at the same time suppress the adsorption of deoxyadenosine and serotonin,thus the selectivity of cis-diol substance was improved.Besides,the adsorbent showed fast adsorption for cis-diol containing molecules.