Thiol-epoxy click polymerization for preparation of polymeric monoliths with well-defined 3D framework for capillary liquid chromatography.

Abstract

A facile approach was developed for direct preparation of organic monoliths via the alkaline-catalyzed thiol-epoxy click polymerization. Two organic monoliths were prepared by using tetraphenylolethane glycidyl ether as a multiepoxy monomer, and trimethylolpropane tris(3-mercaptopropionate) and pentaerythritol tetrakis(3-mercaptopropionate) as the multithiol monomer, respectively, in the presence of a ternary porogenic system (DMSO/PEG200/H2O). The obtained organic monoliths showed high thermal, mechanical and chemical stabilites. Benefiting from the step-growth polymerization process, two organic monoliths possessed well-defined 3D framework microstructure, and exhibited high permeabilities and column efficiencies in capillary liquid chromatography. A series of neutral, basic and acidic small molecules were used to comprehensively evaluate the separation abilities of these monoliths, and satisfactory chromatographic performance with column efficiencies ranged from 35,500 to 132,200 N/m was achieved, demonstrating good separation abilities of these organic monoliths prepared via thiol-epoxy click polymerization approach. Besides, multiple retention mechanisms, including hydrophobic, hydrophilic and π-π conjugate interactions were observed during the separation of analytes on these monoliths, which would make them promising for more extensive applications in capillary liquid chromatography.