“One-Pot” Process for Fabrication of Organic-Silica Hybrid Monolithic Capillary Columns Using Organic Monomer and Alkoxysilane

Abstract

A "one-pot" process for the preparation of organic-silica hybrid capillary monolithic columns by concurrently using organic monomers and alkoxysilanes was described. In this process, the hydrolyzed alkoxysilanes of tetramethoxysilane (TMOS) and vinyltrimethoxysilane (VTMS) as precursors for the synthesis of a silica-based monolith using the sol-gel method and the organic monomer (allyldimethyldodecylammonium bromide (ADDAB) or acrylamide (AA)) with vinyl groups for free radical polymerization along with the initiator of azobisisobutyronitrile (AIBN) were concurrently introduced into a pretreated capillary; after that, the polycondensation of alkoxysilanes and the copolymerization of organic monomers and as-precondensed siloxanes were subsequently carried out within the confines of a capillary at the proper reaction conditions. Two types of organic-silica hybrid capillary monolithic columns with hydrophobic and hydrophilic properties have been fabricated, respectively, by this "one-pot" process using two different organic monomers of ADDAB and AA. The morphologies of the synthesized organic-silica hybrid monolithic columns were characterized by scanning electron microscopy (SEM). The performances of these organic-silica monolithic columns were investigated by capillary electrochromatography (CEC). The retention behaviors of the neutral and polar compounds on the resulting hydrophobic and hydrophilic organic-silica hybrid monolithic columns confirmed the successful incorporation of organic monomers in the silica monolithic matrix. In addition, the ADDA-silica hybrid capillary monolithic column was also applied in the analysis of tryptic digests of bovine serum albumin (BSA) and mouse liver extract by microliquid chromatography-tandem mass spectrometry (microLC-MS/MS) for demonstrating its potential in proteome analysis.