Photopolymerized organo-silica hybrid monolithic columns: Characterization of their performance in capillary liquid chromatography

Porous hybrid organo‐silica monoliths have been prepared inside pretreated 100 μm id UV transparent fused‐silica capillaries using simultaneous sol‐gel transition and polymerization of 3‐(methacryloyloxy)propyl trimethoxysilane in the presence of toluene as a porogen. The sol‐gel reaction was catalyzed by hydrochloric acid while various photoinitiators including azobisisobutyronitrile, 2,2‐dimethoxy‐2‐phenylacetophenone, and Irgacure 819 were used for the photopolymerization carried out under irradiation with UV light at a wavelength of 254 or 365 nm. The chromatographic performance of photopolymerized monolithic columns in RP liquid chromatographic mode was assessed with respect to the following metrics: column efficiency, methylene and steric selectivity, effect of silanol groups, van Deemter plot, permeability, and pore size distribution. Columns with an efficiency of up to 77 000 plates/m for benzene has been achieved at a flow velocity of 0.47 mm/s. The performance of photopolymerized hybrid monolithic column was compared to the performance of columns prepared via thermally initiated polymerization.