Study On Solid-phase Extraction Sorbent For DBT Made By Molecular Imprinting

After the article about preparation of molecularly imprinted polymer for separation of bronchodilator of theophyline and antipsychotic was published in Nature in 1993 by Mosbach, the number of publication about MIP is increasing tremendously every year. Now molecularly imprinted polymer is one of the most promising technologies and has been applied in a variety of different fields, such as in enantiomer separation, solid-phase extraction, biosensor recognition, artificial enzyme catalysis, pharmaceutical analyses.By investigating the application of MIP in solid-phase extraction, we summarize the characteristics of bulk polymerization, dispersion polymerization, precipitation polymerization, in the areas of effect principle, binding capacities, selective recognition of MIP, and generalize the effect factors on polymerization. To prepare highly selective solid-phase extraction sorbent for dibenzothiophene, the batch ways was used to investigate the effects of different monomers and porogens on the selectively binding ability of molecularly imprinted polymer. The results showed that by 4-vinglpyridine(4-VP) as functional monomers, toluene as porogens, the molecularly imprinted polymer has highly binding capacities and selective recognition to the DBT. Maximum binding capacities measures 48.3mg/g. Bulk polymerization has many merits, such as reaction condition facility controlling and simple equipment, however, bulk polymerization has a disadvantage that MIP need to be grounded into particles, subsequently the process of sieved and sedimented is wasteful and time consuming. The result usually is polymer powder with the relatively broad distribution particle size.By dispersion polymerization, we prepared the uniform sized imprinted polymer macro-porous beads, and investigated the effect of the stirring, stabilizer dosage, monomer concentration, initiator concentration on particle size and size distribution. We obtained macro-porous beads (20μm) adapting for stationary phase of chromatographic under the optimal conditions of preparation. The optimizedconditions of stirring, stabilizer dosage, monomer concentration and initiator concentration are 300r/min, 1:12, 0.3% and 0.63% respectively. By packing into extraction column. We measured the dynamic binging isotherm of MIP for DBT.Although we can obtain imprinted polymer with macro-porous beads in specified size with dispersion polymerization, it is difficult for us to prepare stationary phase of chromatographic under strict conditions of dispersion polymerization. So it is very necessary to find better method to imprinted polymer with macro-porous beads. We prepared imprinted polymer beads that had specified binding capacities with DBT through precipitation polymerization, and researched on the effects of concentration of monomer and initiator on polymer beads diameter and configuration. By developing tradition accession method to reiterating technique, we prepared imprinted polymer beads in particle diameter of 1.3μm. Through applying dispersion polymerization and precipitation polymerization into MIP, we master fundamental rule of preparation of imprinted polymer with macro-porous beads. The Predicting and recognizing imprinted polymer with macro-porous beads can be widely used in fields of enantiomer separation, capillary electrophoresis and minim solid-phase extraction.