Synthesis And Characterization Of Magnetic Luteolin Imprinted Polymer

Molecular Imprinting Technology is a chemical analysis and separation technology that rapidly developed in the1980’s, which is a cross discipline involved with chemistry, macromolecule, biology, material, and have a good prospect of application in solid phase extraction, chemical analysis, separation and purification of natural products, biomimetic sensor, simulation of antibody, mimic enzyme, membrane separation technology, separation of chiral drugs and clinical drug analysis.In this thesis, molecular imprinting polymers and magnetic molecular imprinting polymers with luteolin as template molecule were synthesized by suspension polymerization and their application performance were evaluated. The main results are as follow:1.The molecularly imprinted solid phase extraction for bamboo leaf flavone separation was eatablished. Condition the tube with methanol or acetonitrile, followed by2mL of aqueous solution similar to the sample. To remove unwanted, weakly retained materials, wash the packing with10%methanol aqueous solution. Then rinse the tube with10mL methanol and the eluate is collected. The prepared MIPSPE had high adsorption to template molecule and similar structure flavonoids, the flavone yield rate of orientin、 isoorientin、vitexin、isovitexin、meletin and luteolin was88.38%、96.64%、87.64%、86.82%、82.49%、81.74%respectively, the recoveries of the five flavonoids orientin、 isoorientin、vitexin、isovitexin、meletin and luteolin were104.8%、109.1%、52.8%、96.3%、89.2%、97.1%respectively2. A magnetic molecularly imprinted polymer (MMIP) of luteolin was prepared by a dispersion polymerization route with4-ethylpyridine as monomer, ethylene glycol dimethacrylate (EGDMA) as crosslinking agent, azodiisobutyronitrile (AIBN) as an initiator, and modified Fe3O4nanoparticles as a core.The preparated MMIPs surface morphology and its particle size were observated by field emission scanning electron microscopy, it showed that the MMIPs was good spheroid form and their size could be tuned range from about100μm to800μm; the X ray diffractometer was used for MMIPs diffraction, the results showed that nanometer Fe3O4particles was encapsulated in polymer shell; by using FTIR spectrometer for determination of pyridine IR absorption peaks, the results indicated that the magnetic core was successfully wrapped up by polymerization of4vinyl pyridine with EGDMA, and the surface containing carboxyl; MMIPs magnetic properties were measured by using a vibrating sample magnetometer, its saturated magnetic response strength was10.473emu/g; the pore size distribution and specific surface area were determinated by using automatic porosity analyzer and NOVA4200e specific surface area analyzer, the results showed the big hole was mainly distributed in20-210μm, microporous was mainly distributed in0.1-0.007μm, its specific surface area was416.652m2/g; by means of thermogravimetric analyzer for MMIPs thermal stability test, measured at285.7℃to1000℃, two periods of weightlessness occured, the content of Fe3O4was16.56%.3. The results of adsorption kinetics of MMIPs showed that the adsorption achieved equilibrium at about210min, and the adsorption rate of six kinds of flavones were all around90%; Scatchard analysis showed that the MMIPs recognized template with two classes of binding sites. One dissociation contant and maximum apparent binding capacity of MMIPs towards luteolin was KD1=9.3μmol/L, Qmax1=139.46μmol/L, the other one was KD2=129.8μmol/L, Qmax2=248.23μmol/L.4. Recovery experiment was carried out by flavone powder preparation solution and homemade bamboo leaves extract solution as matrix. The results showed that the spiked-recovery of oreitin、isooreitin、vitexin、isovitexin、meletin and luteolin was61.79%、55.39%、69.76%、77.98%、39.85%、98.64%and80.09%、64.15%、77.89%、83.14%、42.07%、95.24%respectively. For the template molecule recovery rate was the highest, up to about95%, the recovery rate of different flavonoids had big difference. With the preparation of magnetic molecularly imprinted polymer as the separation medium, by one times after the separation, flavone extraction experiment results showed that, five kinds of flavones content by3%prior can reach about50%.