Clicking the Stationary Phase on Superficially Fibrous Organo-Silica Particles for HPLC

Silica particles are the most commonly used support materials in high-performance liquid chromatography (HPLC) column technology, owing to their beneficial chemical and physical properties. Among different types of silica particles, superficially porous silica particles (SPPs) exhibit superior chromatographic qualities compared to their fully porous and non-porous silica counterparts. Our research effort centered on developing organo-silica materials for HPLC and other liquid phase separations techniques due to their enhanced hydrolytic stability. Accordingly, we have developed superficially porous organo-silica (SP-FOS) layers with radially oriented pores (ROPs) on core silica particles. The organo-silica hybrid was achieved by incorporating a silane with propyl-azide functionalities during the micellar templating synthetic process of the otherwise inorganic silica layer. The incorporation of organic components into the silica is expected to enhance its hydrolytic stability. Additionally, it introduces surface azido groups, which provide a basis for further functionalization through the well-known Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction, often referred to as click chemistry. This provides a facile method to introduce desired stationary phases onto the hybrid silica. Our investigation of the hybrid fibrous silica delves into various aspects of its fabrication, which includes synthetic parameters such as silane addition rate, micelle swelling agent, micelle concentration, and stirring rate, and how these affect pore diameter and fibrous shell thickness. We intend to evaluate how well the SP-FOS particles perform in chromatographic columns under HPLC conditions. In this presentation we will discuss the fabrication and physicochemical characterization of the fibrous organo-silica shell with ROPs containing azido functionalities, along with an initial, preliminary assessment under HPLC conditions after surface functionalization via click chemistry.