In Situ Growth of Covalent Organic Framework Shells on Silica Microspheres for Application in Liquid Chromatography

A facile, in situ growth strategy for the synthesis of monodispersed COF@SiO2 microspheres is reported. The microspheres have uniform and controllable COF shells, and are used as the stationary phase for HPLC. The TpBD COF, constructed from 1,3,5-triformylphloroglucinol (Tp) and benzidine (BD), is taken as the COF shell, and aminosilica (SiO2-NH2) is employed as the core to support the TpBD shell. The TpBD shell thickness is adjusted by controlling the concentrations of the Tp and BD monomers. The TpBD@SiO2 packed columns show excellent hydrophobic selectivity, and good reproducibility for the separation of neutral (toluene and ethylbenzene, polycyclic aromatic hydrocarbons), acidic (hydroquinone, p-cresol, and p-chlorophenol), and basic molecules (nucleobases, nucleosides, and deoxynucleosides).