Base-deactivated and alkaline-resistant chromatographic stationary phase based on functionalized polymethylsilsesquioxane microspheres.

Abstract

Vinyl, chloropropyl, and mercaptopropyl functionalized particles were prepared by a two-step acidic/alkaline catalyzed co-hydrolysis/condensation of methyltrimethoxysilane with a different silane precursor that carries chemically reactive functional group including vinyl, chloropropyl, and mercaptopropyl, respectively. The morphology, pore structure, and functional groups of the synthesized packings were studied by SEM, nitrogen adsorption-desorption measurements, and solid-state 13 C 29 Si NMR spectroscopy, respectively. The particles show ordered sphere, narrow particle size distribution, and mesoporous structure. The carbon contents of the microspheres are in the range of 17-19%, comparable to those of octadecyl-bonded silica packings. The three-kind of microspheres were directly used as packing materials for high-performance liquid chromatography without size classification. The chromatographic performance of the columns was evaluated and compared with a commercially available C18 phase. The results revealed that these columns possess typical reversed-phase chromatographic properties with increased hydrophobicity than polymethylsilsesquioxane and symmetric peaks for basic compounds. They were applied to the simultaneous separation of combination bendazol hydrochlorothiazide capsules containing polar and basic drugs with peaks identified by tandem with mass spectrometry. In general, a novel method is provided for the synthesis of different methyltrimethoxysilane-derived microspheres for high-performance liquid chromatography, which are advantageous for separating basic compounds.