Preparation and characterization of neutral poly(ethylene glycol) methacrylate-based monolith for normal phase liquid chromatography

A novel porous poly(ethylene glycol) methacrylate-based monolithic column for normal phase liquid chromatography was prepared by thermally initiated polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) and ethylene dimethacrylate (EDMA) in the presence of selected porogens. The monolith was macroscopically homogeneous, had low flow resistance, and did not swell or shrink significantly in solvents of different polarities. Inverse size-exclusion data indicate that the monolith had a total porosity of 79.2%, including an external porosity of 69.3% and an internal porosity of 9.9%. Due to its mild polarity (hydrophilicity), the PEG-functionalized monolith could perform traditional normal phase chromatography using non-polar solvents The van Deemter plot demonstrated that the column efficiency of 33,600–34,320 theoretical plates/m could be achieved at a linear flow velocity of 0.9–1.5 mm/s. The dual retention capability (both weak hydrophilic and hydrophobic interactions) investigated in this paper explains well why the PEG-functionalized monolith could operate in various chromatographic modes.