Fabrication of highly cross-linked reversed-phase monolithic columns via living radical polymerization

• Improved control of polymer monolith morphology was obtained for capillary LC.
• Tellurium-mediated living radical polymerization was used for the first time.
• High plate numbers were obtained for reversed-phase separations of alkylbenzenes.

New monolithic reversed-phase liquid chromatography (RPLC) stationary phases based on single multi-acrylate/methacrylate-containing monomers [i.e., 1,12-dodecanediol dimethacrylate (1,12-DoDDMA), trimethylolpropane trimethacrylate (TRIM) and pentaerythritol tetraacrylate (PETA)] were synthesized using organotellurium-mediated living radical polymerization (TERP), which was expected to produce more efficient monolithic columns than conventional free-radical polymerization. The rationale behind selection of porogens, relative concentrations of reagents and polymerization conditions are described. The new monolithic columns were applied to the separation of small molecules (i.e., alkylbenzenes) under isocratic conditions. Chromatographic efficiencies as high as 60,200 plates/m (71,300 plates/m when corrected for extra-column variance) were obtained, showing a general improvement over previous RPLC monoliths.