Initially, optimization of preparation conditions towards enhanced performance of thermally polymerized organo-silica hybrid monolithic capillaries was considered including variations in the amount of a porogen, the concentration of an aqueous acid catalyst and adjustment in polymerization temperature and time. Furthermore, the chromatographic performance of these capillaries was assessed in terms of column efficiency, retention of homologous series of alkylbenzenes, polar analytes, and sterically similar compounds and compared with that of photopolymerized hybrid monolithic capillaries. Subsequently, organic functionalities exposed on the pore surface of the parent monolith enabled modification using thermally and photoinitiated grafting as well as thiol-ene click chemistry. The highest increase in column retention of alkylbenzenes was observed for monolith modified with two-step sequential photografting with N-octadecyl methacrylate. However, this approach resulted in undesired decrease in column efficiency with increased amount of monomer in the polymerization mixture. On the other hand, thiol-ene click chemistry with 1-octadecanethiol proved to be valuable for functionalization without significant decrease in column efficiency. The applicability of thiol-ene click chemistry is further demonstrated using other monomers.

Hydrophobic surface modification of organo-silica hybrid monolithic columns using photografting and thiol-ene click chemistry

249th National Meeting (2015)

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