title: Cross-linker effects on the separation efficiency on (poly)methacrylate capillary monolithic columns. Part II. Aqueous normal-phase liquid chromatography.
abstract: We synthesized seven different polymethacrylate monolithic capillary columns using N,N-dimethyl-N-metacryloxyethyl-N-(3-sulfopropyl) ammonium betaine functional monomer (MEDSA) and various cross-linking monomers differing in the polarity and size. The efficiency of monolithic columns for polar low-molecular compounds in the aqueous normal-phase (HILIC) mode depends rather on the polarity, than on the size of the cross-linker molecules. Cross-linking molecules, which exhibit high polarity can produce poly(methacrylate) monoliths with an increase in pore sizes below 50nm. Columns prepared with pentaerythritol triacrylate or bisphenol A dimethacrylate cross-linkers show large inner pore (mesopore) porosity, and provide poor efficiency, whereas columns with trioxyethylene dimethacrylate (TriEDMA) and tetraoxyethylene dimethacrylate (TeEDMA) cross-linkers showed poor permeability. Columns prepared using dioxyethylene dimethacrylate (DiEDMA), and especially glycerolate dimethacrylate (BIGDMA) cross-linkers, showed best efficiency, with more 60,000-70,000 theoretical plates/m, almost twice in comparison to (poly)methylene dimethacrylate (HEDMA) in the HILIC mode. All columns show dual retention mechanism and can be used for separations of low-molcular compounds such as phenolic acids in the HILIC mode in acetonitrile-rich mobile phases and in the reversed-phase mode in mobile phases with higher concentrations of water. Some columns show broad pore distribution and can be used for size-exclusion chromatography of non-polar polymers in tetrahydrofuran.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic.
authors.forename: Magda
authors.initials: M
authors.lastname: Staňková
authors.forename: Pavel
authors.initials: P
authors.lastname: Jandera
authors.forename: Veronika
authors.initials: V
authors.lastname: Škeříková
authors.forename: Jiří
authors.initials: J
authors.lastname: Urban
mesh_terms: D002853:Chromatography, Liquid / Q000295:instrumentation*; D011108:Polymers / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D016062:Porosity; D012117:Resins, Synthetic / Q000737:chemistry*
chemical_list: D011108:Polymers; D011109:Polymethacrylic Acids; D012117:Resins, Synthetic; C030613:polymethacrylic acid