Sorption Preconcentration of Quercetin Using Molecularly Imprinted Phloroglucinol–Melamine–Formaldehyde Resins

Abstract

Hydrophilic quercetin-imprinted phloroglucinol–melamine–formaldehyde resins are obtained. The obtained samples are studied by Fourier-transform IR spectroscopy and laser diffraction. The phloroglucinol–melamine ratio (3 : 1) is optimized at the sorption capacity of the molecularly imprinted resin (1.7 μmol/g) with respect to quercetin 2.6 times higher than that of the non-imprinted resin. It is shown that the kinetics of quercetin rebinding by both molecularly imprinted and non-imprinted resins obeys the pseudo-second order model, and the isotherms follow the Freundlich model, which indicates the inhomogeneity of the resin surface. The resin imprinted with quercetin demonstrated high selectivity to morine (a structural analogue of quercetin of the flavonol class) and caffeine. At that it is shown that quercetin can be used as a pseudotemplate for the separation and preconcentration of naringenin (a representative of flavanones) and rutin (a representative of flavonols).