A Sol–gel Method for Preparing Poly (N-Isopropyl Acrylamide) Hybrid Column and Its Application in Small Molecular Analysis Using Capillary Liquid Chromatography

A poly ( N -isopropyl acrylamide) (polyNIPA)-based hybrid column for capillary liquid chromatography (cLC) was prepared with N -isopropyl acrylamide (NIPA) and alkoxysilanes through a sol–gel “one-pot” method. In this process, the hydrolyzed tetramethoxysilane (TMOS) and vinyltrimethoxysilane (VTMS) were the precursors for the synthesis of a silica-based monolith and subsequently reacted with organic monomer (NIPA) via free radical polymerization within the confines of a capillary. The effects of polymerization temperature, the volume of TMOS, VTMS, and acetic acid (HAc) as well as the amount of progens [polyethylene glycol 10,000 (PEG10000) and urea] on the morphology and permeability were investigated in detail. Uniform pore structure and good mechanical stability were obtained for columns prepared under optimized conditions. Separation of various neutral, acidic and basic analytes was achieved by cLC in reversed-phase liquid chromatography (RP-LC) mode. Moreover, the resulting hybrid column was also applied for the analysis of small organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), perfluorinated compounds (PFCs) and chlorophenols (CPs). The successful application demonstrated its potential in the separation of small molecules.