Studies On Preparation And Characteristics Of Molecular Imprinted Solid-phase Extractants

Molecular imprinting technology is a kind of new-emerging polymerizing technology,which produces molecule recognition materials with high selectivity and affinity.Polymerization is occurred between functional monomers and crosslinker around template molecules.After extraction of the template molecules,molecular imprinted polymers(MIPs) with specifically memory to the template molecules are obtained.Thus,MIPs can be created to recognize a target molecule with affinity and selectivity comparable to natural receptors and were called as "artificial antibody".And these materials can withstanding much harsher conditions than(?)ntibodies,such as high temperature,pressure,extreme pH,and organic solvents.These properties have made them extremely attractive for solving problems in the fields of preparative chemical separations,purification and sensors, or for the removal of specific molecular targets from complex mixtures. Solid phase extraction(SPE) is the most popular sample preparation method with the high efficiency and reliability,molecular imprinted solid-phase extractants can overcome shortcomings of traditional extractants,and advance the selectivity of SPE.The work mainly included the following items:(1) By bulk technique,phenol-MIPs were synthesized using 2-vinylpyridine as functional monomers,ethylene glycol dimethacrylate as crosslinker,azoisobutyronitrile as initiator and phenol as template molecules in the solvent of chloroform.The best experimental condition of preparing MIPs was studied.The influence factors of MIPs dosage and temperature on adsorption capacity was discussed.Adsorption capacity of MIPs was studied by Scatchard analysis.Selectivity and reusability of MIPs were studied.The configuration of IIP and its materials were characterized by FT-IR spectra,UV-spectra,SEM.The results indicated that the best experimental condition of preparing phenol-MIPs is molar ratio of phenol,2-Vpy and EDMA was 1:2:10, 6mL of solvent.Effect of temperature on adsorption capacity was little, and MIPs dosage was 30mg.Scatchard analysis showed that the dissociation content(Kd) and the apparent maximum binding capacity(Qmax) were Kd=1.31mmol/L,Qmax=120.7μmol/g.MIPs had a good selective binding property with phenol.The reusability of MIPs was stable.(2) By bulk technique,Ni(Ⅱ)-IIPs were synthesized using 2-vinylpydine and acrylamide as functional monomers,ethylene glycol dimethacrylate as crosslinker and azoisobutyronitrile as initiator a in the mixture solvent of chloroform and methanol(V:V=3:2).The influence factors of IIPs dosage,pH,time and temperature on adsorption efficiency were investigated.Effect of initiative concentration was studied.And selectivity and reusability of IIP were studied.The configuration of IIP and its materials were characterized by FT-IR spectra,SEM and EDS.The results indicated that the best of adsorption condition was that IIP dosage was 50mg,pH was 5.0,adsorption time was 40min.Within the initiative concentration studied,saturated extent of adsorption of IIPs and NIPs was 29.3mg/g and 14.1mg/g respectively. IIP had a better selective binding property to Ni(Ⅱ),while competitive icons of Mn(Ⅱ),Co(Ⅱ),Cu(Ⅱ),Zn(Ⅱ) and Cd(Ⅱ) were mixed in solution.The reusability of MIPs was good after being resued five times.(3) Ethanol precipitation was applied to purify chondroitin sulfate, and the yield of chondroitin sulfate was 97.5%.By bulk technique, ChS-MIPs were synthesized using acrylamide and methacrylic acid as functional monomers,ethylene glycol dimethacrylate as crosslinker, azoisobutyronitrile as initiator and chondroitin sulfate as template molecules in the mixture solvent of acetonitrile and H2O.The best preparation condition of polymers was studied.Effects of ChS-MIPs dosage and initial concentration and adsorption time on adsorption capability.Adsorption capacity of ChS-MIPs was compared with that of NIPs.The polymers were characterized by FT-IR and SEM.The results indicated that the best experimental condition of preparing ChS-MIPs was molar ratio of ChS,AM,MAA and EDMA was1/n:4:4:40(n=60), 6mL mixed solution of acetonitrile and H2O(V:V=85:15).MIPs dosage was 30mg,adsorption was about in equilibrium in 10 hours.Within the initiative concentration studied,saturated extent of adsorption of ChS-MIPs.