Synthesis of monolithic HPLC stationary phase with self-assembled molecular recognition sites for 4-aminophenol

A molecularly imprinted polymer (MIP) monolith for selective recognition of 4-aminophenol (4-AMP) was prepared by in situ polymerization technique as high-performance liquid chromatography (HPLC) stationary phase. For this purpose, several 4-AMP imprinted monoliths were synthesized by using only methacrylic acid (MAA), acrylamide (AAM), or isobornyl methacrylate (IBMA) in the presence of high amount of crosslinker, ethylene glycol dimethacrylate (EDMA), and these polymeric monolith columns were connected to HPLC to evaluate their separation capabilities. By selection of appropriate functional monomer and optimization of polymerization conditions, MAA-based monolithic MIP showed good flow through properties, high selectivity to the templated molecule, and high resolution in the separation of paracetamol and its main impurity, 4-AMP. Besides, effective binding site density and dissociation constant of this monolith were estimated by using frontal chromatography and found as 7.95 μmol/g and 1.06 mM, respectively. Surface area of the same monolith was found as 23.48 m²/g from multipoint BET analysis.