Detection of organic amines in liquid with chemically coated quartz crystal microbalance devices

Abstract

Six kinds of materials, i.e. three self-assembled monolayers with terminal functional groups, a polymer incorporating acid groups, and two supramolecules of calixarene derivatives were applied as QCM sensor coatings for selective detection of organic amines in liquid phases. The specific interactions such as acid-base interaction, complexation interaction between the coating materials and analytes make the coated QCMs sensitive to organic amines in aqueous phase. The characteristics of the coated QCM sensors varied with the detection media because of the changes of the physico-chemical properties of the coating surfaces. Reversible changes in resonance frequency of the coated QCMs were found in neutral water solution for acid-base interaction and hydrogen bonding; quasi-irreversible frequency changes were found for salt-complex forming reaction in buffer solution. The relative selectivity of the analytes decreased with the increase of the hydrophobic part of the solute molecules in aqueous phases when acid-base interaction between the coating materials and analytes were employed. Shape-discrimination of analytes were achieved by the usage of supramolecules as sensor coatings owing to the cavity inclusion of the supramolecules. © 1997 Elsevier Science S.A.