| The molecular imprinting technology is a new separation technique which attracts more and more attention recently. As an environmental friendly solvent, ionic liquid was widely used in various industries at present. In this paper, one-step synthesis method was used to obtain the functionalized ionic liquids, which can be used as a functional monomer to synthesize molecularly imprinted polymers(MIPs), and the selective adsorption of synephrine was studied by the way of molecular imprinting technology.Four ionic liquids containing carboxylic acid were synthesized,[COOHevim]Br、[COOHpvim]Br、[COOHavim]Br、[COOHhvim] Br respectively. Through the calculation of pKa value we could draw a conclusion that the shorter its carbon chain, the stronger its acidity. The result was testified by IR spectral probes, and also demonstrated the1-vinyl-3-acetoxyimidazolium bromide had the strongest acidity. By changing the length of carbon chains, the acidity of ionic liquids can be regulated.The MIPs are synthesized by using synephrine as the template molecular, the obtained functionalized ionic liquid as the functional monomer, EDGMA as the cross-linking agent and azobisisobutyronitrile (ABIN) as the initiator in methanol-water system via a precipitation polymerization method. The influence of several parameters on MIP preparation was investigated, including the kinds of functional monomer and the difference of solvent. The absorption ability of the MIP is studied by static adsorption method and Scatchard curve and equation. The adsorption and selectivity in ageous solution was compared between MIP synthesized by common functional monomer and MIP synthesized by ionic liquid.The MIP was used as adsorbent of solid-phase extraction (SPE) and the selectivity of synephrine and its analog is discussed. Molecularly imprinted solid-phase extraction (MISPE) showed that the MIP could effectively separate and purify synephrine in the extraction of citrus aurantium. |
PDF Full Text Request