Preparation of a polyhedral oligomeric silsesquioxanes hybrid monolith via a single-step ring-opening polymerization for pressurized capillary electrochromatography.

An organic-silica hybrid monolith was prepared by a single-step ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS-epoxy), polyethylenimine (PEI), and β-cyclodextrin (β-CD) in a ternary porogenic solvent consisting of polyethylene glycol, 1,4-butanediol, and 1-propanol. The framework of POSS-PEI hybrid monolith could offer well-defined 3D skeleton, while β-CD with the ability of forming a host-guest inclusion complexes with a variety of compounds could show an ability of specific selection. The obtained hybrid monoliths were successfully applied for separation of phenols, benzoic acids, and nucleobases. Especially due to the introduction of β-CD, positional isomers including hydroquinone and resorcinol, o-nitrophenol and p-nitrophenol, as well as p-chlorophenol and o-chlorophenol were baseline separated and the column efficiency reached 82 300 plates/m for hydroquinone.