Monodispersed submicron porous silica particles functionalized with CD derivatives for chiral CEC

Rapid and efficient enantioseparation of halogen aryl alcohols and β-blockers propranolol and pindolol in packed bed CEC (p-CEC) using as-prepared submicron porous silica chiral stationary phases (CSPs) has been achieved. Monodispersed 0.66 and 0.81 μm chiral submicron porous silica spheres were prepared using tetramethoxysilane and hexadecyltrimethylammonium bromide, followed by a hydrothermal treatment method with ammonia-ethanol to expand the pore of silica spheres without changing their spherical morphology. A proper specific surface of ca. 230 m²/g and pore sizes average of 6-8 nm were obtained by this method. The submicron porous silica spheres were modified with mono-6-phenylcarbamoylated β-CD via thiol-en radical addition. They were packed into 9 cm 50 μm id capillary columns with photopolymerized monolithic frits. These submicron CSPs showed greater column efficiency (about 476 000 plates/m for 4-iodophenyl-1-ethanol) and higher resolution than the corresponding 3 μm CSP.