Preparation Of Nicotine-imprinted Polymer Microspheres By Emulsion Suspension Polymerization

In this study, nicotine molecular imprinted copolymer(NMICP) micro/nanospheres were prepared by emulsion suspension polymerization directly, using melamine-urea-formaldehyde(MUF) gel as functional monomer and nicotine as template. With stirring the mixture of kerosene and MUF gel at high speed(10,000 rpm), the water in oil(W/O) emulsion was prepared. Then the polymerization reaction was started with hydrochloric acid as initiator when standing for 24 h. After removal of the template nicotine, NMICP micro/nanospheres were obtained. The morphology and structure of the products were characterized by scanning electron microscopy(SEM). The pictures indicated that the imprinted materials were uniformly-sized particles with skullcap shape and the average diameters of NMICPs micro/nanoparticles are less than 10 μm.The adsorption performance of imprinted polymer and non-imprinted control polymer(NIP) were evaluated by equilibrium rebinding experiments. The results demonstrated that NMICPs had specific adsorption sites and achieved high adsorption ability compared with NIP. Scatchard analysis indicated that the adsorption amount increased with the ratio of template and functional monomer(T/M) increasing, but not in proportion to the T/M.The molecular imprinted polymer-solid phase extraction(MISPE) and elution experiments were performed with NMICPs as sorbent materials to evaluate the adsorption and elution performance of NMICPs. The experiment indicated that the interaction between the recognition sites and the target was non-covalent, and either water or methanol aqueous solution was able to disrupt the specific interactions. It also illustrated that the content of nicotine eluted from the NMICPs was decreased with the T/M increased.The NMICPs were applied as sorbents in SPE of extracting alkaloids from tobacco leaf real samples, which showed the amount of nicotine obtained by MISPE was 1.4-fold to those obtained by traditional liquid liquid extraction(LLE). NMICPs showed different selectivity performances for nicotine and other alkaloids, which indicated that NMICPs showed selectivity for nicotine. Therefore, the NMICPs micro-particles are good solid sorbent to enrich and separate the alkaloids from the complex bio-sample in the future.