Bionic multi-tentacled ionic liquid-modified silica gel for adsorption and separation of polyphenols from green tea (Camellia sinensis) leaves.

For the first time, a new kind of bionic multi-tentacled ionic liquid-modified silica gel was synthesized and used as selective adsorbent in the preparative separation of tea polyphenols (TP) from green tea leaves. It was found that silica particles with polyvinyl alcohol chains modified by N-methyl imidazole proline salt (PVA·Im+·Pro-@SiO2) had the excellent performance in selective adsorption as well as fine separation for target compounds. The new adsorbent exhibited high adsorption capacity and good reusability, meanwhile the antioxidant activity of TP could be improved through its efficient enrichment. It properties and adsorption mechanism were also investigated comprehensively and compared with those reported sorbents. Finally, the preparative separation of individual catechin from crude extracts was successfully achieved on the chromatographic column packed with PVA·Im+·Pro-@SiO2 particles and four main constituents were obtained successively. The study was expected to provide a new way for the effective separation of similar bioactive compounds.