Monolithic capillary columns based on silica and zirconium oxides for use in hydrophilic interaction liquid chromatography

Capillary monolithic columns (100 μm i.d.) of silica and zirconium oxides were prepared by the sol-gel process (SGP) for use in hydrophilic interaction liquid chromatography (HILIC). The monoliths were characterized by physicochemical and chromatographic techniques. The physicochemical characterizations were performed by utilization of optic and electronic microscopies, thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, solid-state 29Si CP-MAS NMR spectroscopy, and elemental analysis. The chromatographic characterization used a mixture containing aromatic hydrocarbons with different polarities. The results presented in this paper demonstrate a simple synthetic approach based on the sol-gel process to produce polar silica and zirconia monolithic stationary phases (SP) with good chromatographic performance. These monolithic capillary columns were used in the HILIC mode in capillary liquid chromatography (cLC).