Methacrylate monolithic columns of 320 μm I.D. for capillary liquid chromatography

Monolithic capillary columns (320 μm I.D.) were prepared for capillary liquid chromatography (CLC) by radical polymerization of butylmethacrylate (BMA) and ethylenedimethacrylate (EDMA) in the presence of a porogen solvent containing propan-1-ol, butane-1,4-diol and water. The influence of the contents of the porogen solvent and EDMA in the polymerization mixture on the monolith porosity and column efficiency was investigated. The composition of the polymerization mixture was optimized to attain a minimum HETP of the order of tens of μm for test compounds with various polarities. The separation performance and selectivity of the most efficient monolithic column prepared was characterized by van Deemter curves, peak asymmetry factors and Walters hydrophobicity and silanol indices. It was demonstrated that the 320-μm I.D. monolithic column exhibited CLC separation performance similar to that observed for 100- and 150-μm I.D. monolithic columns reported in the literature; moreover, the 320-μm I.D. column was easier to operate in CLC and exhibited a higher sample loadability.