Physical and electrophoretic characterization of octadecyl methacrylate-based monolithic columns for use in capillary electrochromatography

摘要

Organic monolithic columns with high efficiency were obtained for use in capillary electrochromatography (CEC) from a mixture of monomers (constant concentrations) with different proportions of porogenic solvents (1,4-butanediol with isoamyl alcohol, amyl alcohol or cyclohexanol in the presence or absence of water). The stationary phases were prepared from the precursor monomer octadecyl methacrylate (ODMA), the cross-linking agent ethylene dimethacrylate (EDMA) and the ionizable monomer 2-acryloylamido-2-methylpropanesulfonic acid (AMPS), the latter being necessary to make the stationary phase negatively charged, assuring electrosmotic flow (EOF) during analysis. The monolithic columns synthesized were physically characterized by porosimetry and scanning electron microscopy (SEM), and electrochromatographically characterized by calculation of chromatographic parameters. The most efficient column was prepared using the porogenic solvent amyl alcohol:1,4-butanediol in a 65:35 (v/v) ratio and showed a plate height of 38 µm. These columns were applied for the separation of alkyl parabens and polycyclic aromatic hydrocarbons (PAH).