Synthesis of Hybrid Monolithic Columns Using a Click Chemistry Reaction for Application in Capillary Liquid Chromatography

Abstract

Hybrid monolithic columns present characteristics of both silica and organic monoliths, such as good mechanical properties, wide pH tolerance, high permeability and stability and little swelling or shrinkage. A common way to prepare this type of material is by using alkoxysilanes and organic monomers via the sol-gel process and click chemistry reactions. In this paper, a co-condensation organic-silica hybrid monolith was prepared based on tetramethoxysilane (TMOS) and vinyltrimethoxysilane (VTMS) as precursors for the sol-gel process. The hybrid monolithic matrix was modified with dodecanethiol through the thiol-ene click chemistry reaction and the resulting material was compared with a dodecanesilane bonded phase column, in order to evaluate the differences in the chromatographic performance of a stationary phase prepared by a classic reaction or by a thiol-ene click reaction. Additionally, the stability of the thiol-ene column over time was evaluated. The effects of different synthetic proportions were investigated in detail by scanning electron microscopy (SEM), scanning capacitively coupled contactless conductivity detection (sC4D), Fourier-transform infrared spectroscopy (FTIR) and retention behavior in capillary liquid chromatography (cLC). The hybrid monolithic column prepared with dodecanethiol was the best one for the separation of alkylbenzenes and polycyclic aromatic hydrocarbons by cLC-UV.