Preparation of water‐compatible molecularly imprinted polymers for caffeine with a novel ionic liquid as a functional monomer

Abstract

Water-compatible molecularly imprinted polymers (MIPs) for caffeine were synthesized in aqueous medium with a new functional monomer, 1-(a-methyl acrylate)-3-methylimidazolium bromide (1-MA-3MI-Br), which had p-p and hydrogen-bonding interactions. Caffeine-imprinted polymers were prepared in suspension polymerization with 1-MA-3MI-Br and methacrylic acid (MAA), which only had hydrogen bonding, as a functional monomer. For the specific binding characteristics of the new functional monomer 1-MA-3MI-Br, the adsorption capacity and relative separation factor (b) of MIPs for caffeine were significantly enhanced. The maximum adsorption capacities of 1-MA-3MI-Br-MIP and MAA-MIP imprinted microspheres for caffeine were 53.80 and 28.90 lmol/g, respectively. Moreover, the relative separation factors were measured by comparison of the separation characteristics under competitive adsorption conditions. The results showed that the b of MAA-MIP for caffeine relative to theophylline was only 1.65; this showed a very poor recognition selectivity for caffeine, but b of 1-MA-3MI-Br-MIP for caffeine with respect to theophylline was remarkably enhanced to 3.19; this showed an excellent recognition selectivity and binding affinity toward caffeine molecules in an aqueous environment.

The performance optimization and specific adsorption of L-phenylalanine imprinted polymers using 1-vinyl-3-carboxymethylimidazolium chloride as functional monomer

“…A similar observation has also been reported in the literatures by Qian [35] and Luo. [32] However, it is difficult for many MIPs formed by simple interactions, such as hydrogen-bonding interactions between functional monomers and template, to achieve adsorption equilibrium in short time just as the work of Li. [25] In their works, L-Phe-imprinted polymers prepared using MAA as monomers which could interact with L-Phe by hydrogen-bonding interaction achieved adsorption equilibrium after 2 h. This indicated that [VCIM]Cl as monomer could quicken the adsorption of L-Phe obviously though multiple interactions.…”

“…The obtained novel material showed high affinity and selectivity for CS. Then, Luo [32] has successfully prepared caffeine-imprinted polymers in aqueous medium using 1-(α-methyl acrylate)-3-methy-limidazolium bromide as functional monomer which had π-π and hydrogen-bonding interactions with caffeine. The relative separation factor of the obtained polymers could enhance to 3.19, which was higher than MIPs prepared using MAA as monomer.…”

Electrochemical sensor for dimetridazole based on novel gold nanoparticles@molecularly imprinted polymer

“…Hitherto, vinylimidazolium ionic liquids (ILs) are popularly chosen as monomer to solve above disadvantages for the preparation of MIP [4,[16][17][18][19][20][21][22][23]. They not only enhance MIP water-compatible ability, but also decrease MIP particle scale in comparison with traditional monomers.…”

Water-compatible surface imprinting of ‘Saccharin sodium’ on silica surface for selective recognition and detection in aqueous solution

“…In this research silica gel was modified by grafting, and the choice of the crosslinking agent was studied, so that the polymer has a good selective adsorption ability to the target molecule. Luo et al synthesized molecularly imprinted polymers of caffeine on the silica surface in aqueous solution [4]. They choose the novel function monomer 1-(a-methyl acrylate)-3-methylimidazolium bromide (1-MA-3MI-Br) ionic liquid, which has good compatibility with water.…”