Molecularly imprinted polymers with ionic liquid as the functional monomer for selective solid-phase extraction of gastrodin

Abstract

Gastrodia elata is a well-known Asian traditional herb with gastrodin (GAS; p-hydroxymethylbenzene-β-d-glucopyranoside) as its active ingredient. It is a challenging task to efficiently separate the active ingredient gastrodin from Gastrodia elata by simple procedure. The results of computer molecular simulation & UV-vis spectroscopy showed that water-soluble 1-vinyl-3-tetradecylimidazole bromide([C14VIM+] [Br-]) was selected as the best ionic liquid functional monomer compared with methacrylic acid(MAA), acrylic acid(AA), 3-(2-carboxyethyl)-1-vinylimidazolium bromide ionic liquid (imidazole propionate, [COOHpvimBr]), and dehydroabietic acid [2-(acryloyloxy)ethyl] ester (DAAEE). The force between [C14VIM+] [Br-] and GAS (with multiple hydroxyl groups) is stronger than other monomers with more polar groups. The molecular imprinted polymers (MIPs) and non- molecular imprinted polymers (NIPs) with high selectivity to gastrodin were synthesized utilizing ([C14VIM+] [Br-]) as a novel functional monomer. The polymer was characterized by infrared spectrum, scanning electron microscope, specific surface area tester and thermosgravimetric analyser(TGA). The adsorption performance of the polymer was investigated by adsorption kinetics experiment and static adsorption experiment. Among different eluents, the content of gastrodin in eluent (70% ethanol) significantly increased compared with it in plant extract by the MIPs-solid phase extraction (SPE)-HPLC. The recoveries of the spiked samples for the GAS were 97.75–103.43%, with relative standard deviation values lower than 2.88%. This novel [C14VIM+] [Br-]-based MIP was a potential separation material for gastrodin. The graphical abstract was shown below.