Preparation and Evaluation of Organic-Inorganic Hybrid Silica-Based Monolithic Columns for Capillary Electrochromatography

A new type of organic-inorganic hybrid porous silica-based monolithic columns was developed for reversed-phase capillary electrochromatography RP-CEC. The monolithic columns were prepared from in situ co-condensation of tetraethoxysilane TEOS and phenyltriethoxysilane PTES precursors via a two-step catalytic sol-gel procedure in the capillary to create phenyl groups distributed throughout the silica matrix for chromatographic interaction. The functionalized monolithic stationary phase was created without additional surface derivatization. The reaction conditions for the preparation of the monolithic columns were optimized. The structure and pore size distribution of the monolithic columns were characterized by scanning electron microscopy and mercury porosimetry respectively. The effect of water concentration on the column structure was studied and the influence of the ratio of two precursors on the pore size distribution was also investigated. The retention behavior of polycyclic aromatic hydrocarbons on the monolithic column is discussed. Seven phenols were also separated with an average efficiency over 100 000 plates/m.