Preparation of surface molecularly imprinted polymer and selective extraction of 1-methoxyethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide

A new molecularly imprinted polymer was prepared on the surface of ethylenediamine-poly(styrene-divinylbenzene) particles by thermal polymerization method using 1-methoxyethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([EOM][Tf2N]) as template, acrylamide as functional monomer, and chloroform as porogen. The influence of porogen, monomer, and the ratio of [EOM][Tf2N] to monomer and cross-linker was systematically investigated, and the microstructure was characterized by Fouier transform infrared spectrum and scanning electron microscopy. The selective recognition performance of the imprinted polymer for target was investigated by the static adsorption and HPLC. It was shown that the surface imprinted material had excellent selectivity towards [EOM][Tf2N] and the short chain imidazolium ionic liquids, but its adsorption towards the molecules without imidazole ring was quite low. The maximum binding capacities of [EOM][Tf2N] on the imprinted and non-imprinted polymers were 137.2 and 23.4 A mu mol g(-1), respectively. The adsorption equilibrium was achieved in 35 min, and the kinetic adsorption process could be described by pseudo-second order model. From high pressure liquid chromatography measurements, it was found that using the imprinted polymer, 84-91 % [EOM][Tf2N], 10 % 2,4-dichlorophenol, and 3 % N-butylpyridinium chloride could be separated from the mixtures of [EOM][Tf2N] + 2,4-dichlorophenol and [EOM][Tf2N] + N-butylpyridinium chloride, respectively. By contrast, the non-imprinted polymer could adsorb only less than 10 % [EOM][Tf2N], 10 % 2,4-dichlorophenol, and 3 % N-butylpyridinium chloride, respectively, from the mixtures. The imprinted polymer coupled with HPLC was applied for the selective extraction and determination of [EOM][Tf2N] in complex mixture samples.