Synthesis of titania monoliths for chromatographic separations.

Titania monoliths inside capillary columns were prepared from a mixture of titanium propoxide, hydrochloric acid, formamide and water. Several synthesis parameters such as hydrolysis ratio, porogen type, precursor concentration, and drying step have been identified and controlled in order to obtain a macroporous titania monolith, efficient for liquid chromatography, inside a silica capillary. Pure titania monolith with a 10 times higher permeability as compared to a classical packed column was produced, and was able to separate a xanthine test mixture in the LC mode. Even if direct observations with scanning electron microscopy cannot be performed in wet conditions, the homogenous structure of the monolith was demonstrated by the plate height observed during chromatographic separation of xanthines in hydrophilic interaction liquid chromatography.