Nicotine-Selective Polymeric Adsorbent Obtained by Molecular Imprinting with Excess Use of Itaconic Acid

Abstract

Currently, nicotine is mostly analyzed by chromatography with pretreatment such as solid phase extraction (SPE). One of effective pretreatment techniques would be affinity extraction; however, there is no practical biomolecular affinity media available for SPE of nicotine. Molecular imprinting has been studied as a methodology for producing nicotine-selective synthetic affinity media, which relies on the formation of complex species between a target molecule (as template) and functional monomer; therefore, the selection of functional monomer is greatly important for obtaining molecularly imprinted polymers (MIPs) with high affinity and selectivity. In this study, itaconic acid (IA), which bears two carboxyl groups, was used as functional monomer in the synthesis of nicotine selective-MIPs. Other acidic monomers, such as methacrylic acid (MA), 2-(trifluoromethyl)acrylic acid (FM) and methyl itaconate (MI) were compared with IA to evaluate their usefulness as functional monomer. In chromatographic tests, the retention factor for nicotine on a MIP synthesized with itaconic acid (IP-IA16) was 40.4, which was 3.1 times that on a non-imprinted polymer (BP-IA16), while the retention factor on MIPs with the other monomers was 21.6 or less and was 1.1 times that on corresponding non-imprint blank polymers (BPs). In the selectivity test using cotinine, 3-methylpyridine and N-methylpyrrolidine as reference compounds, IP-IA16 showed the largest retention factor for nicotine, which was more than 4.4 times that of the other compounds, suggesting that nicotine-recognition sites were formed in MIPs by the molecular imprinting using IA as functional monomer.