Applicability of core-shell SiO2 microspheres with a high TiO2 loading as stationary phase for HPLC

Background Due to its high chemical stability, sufficient rigidity and zwitterionic ion exchange properties, TiO 2 can be considered as an alternative stationary phase material to SiO 2 for high performance liquid chromatography . TiO 2 stationary phase is usually prepared by coating TiO 2 onto SiO 2 support by sol-gel method. However, in the traditional coating method, in order to overcome the rapid hydrolysis rate of tetrabutyl orthotitanate, only a very low concentration of tetrabutyl orthotitanate can be used, resulting in a low loading of TiO 2 on the support. Results TiO 2 core-shell spheres with a good monodispersity were prepared using 0.25 mol L −1 tetrabutyl orthotitanate. The specific surface area, pore volume , pore diameter and TiO 2 loading of the TiO 2 core-shell spheres were 66 m 2  g −1 , 0.15 cm 3  g −1 , 9.8 nm and 57%, respectively. The core-shell spheres were derivatized with n-octadecyltrichlorosilane and then packed into a stainless steel column to test the separation performance for neutral, basic and acidic samples in liquid chromatography. A baseline separation of polyaromatic hydrocarbons was achieved, showing a column efficiency for fluorene of 118075 plates m −1 . The prepared stationary phase was also used to separate acidic and basic mixtures, and column efficiencies of 54500 and 25836 plates m −1 were obtained for N , N -dinitroaniline and p -chlorophenol, respectively. The relative standard deviations of the retention times of polyaromatic hydrocarbons for run-to-run, day-to-day and column-to-column repeatability were all below 5.1%. Significance and novelty This work demonstrated that TiO 2 can be coated in the pores of the shell of SiO 2 core-shell spheres with high TiO 2 loading using a high concentration of tetrabutyl orthotitanate as the titania source. The experimental results show that the TiO 2 coated core-shell spheres can be a good alternative stationary phase for liquid chromatography.