TiO 2 Coated SiO 2 Core-Shell Stationary Phase with Uniform and Tunable TiO 2 Thickness for High Performance Liquid Chromatography Separation

Abstract

Abstract In this work, TiO2 was coated into the pores of the SiO2 core-shell spheres by using tetrabutyl orthotitanate (TBOT) as the titanium source. Then, by simply prolonging the reaction time, a TiO2 layer with a uniform and controllable thickness was obtained on the surface of SiO2 core-shell spheres by Ostwald ripening. The thickness of the TiO2 layer can be tuned from 15 to about 71 nm by either controlling the reaction time or controlling the amount of TBOT. C18-derived core-shell spheres with a TiO2 layer thicknesses of 40 nm (C18-SST-0.5-60) and 70 nm (C18-SST-0.7-30) were used as packings to evaluate the effect of TiO2 layer thickness on the chromatographic separation performance. The separation efficiency of C18-SST-0.5-60 and C18-SST-0.7-30 for fluorene was 115112 plates m− 1 and 83189 plates m− 1, respectively. Both TiO2-coated core-shell packings showed good peak symmetry for basic samples, with peak asymmetry factors below 1.11. The relative standard deviations of the retention time of polycyclic aromatic hydrocarbons and anilines were all lower than 6%. The results demonstrate that the TiO2 based stationary phase possesses great potential for high performance liquid chromatographic separation.