Sensing performance of Schiff base-calix[4]arene including amide units for detection of pharmaceutically active compounds on QCM sensor system

Abstract

This study aimed to investigate the sensing performance of a Quartz Crystal Microbalance (QCM) sensor coated with a calix[4]arene derivative (calixarene phenol amide, CPhA), containing both Schiff base and amide groups against various pharmaceutically active compounds (PhACs) such as ibuprofen, diphenhydramine, naproxen, and ascorbic acid in aqueous media. CPhA was successfully coated on the QCM crystal surface, and its surface properties were studied using Atomic Force Microscopy (AFM) and contact angle measurements. Sensing studies showed that the CPhA-coated QCM sensor detected more PhACs than the compound 4 (unfunctionalized derivative)-coated sensor. The highest frequency variation and binding ratio values were achieved with the QCM sensor with a relatively low coating amount. The CPhA-coated QCM sensor achieved higher adsorption capacity and was significantly more sensitive to all PhACs than the compound 4-coated one. The fabricated sensor showed remarkable reproducibility for all PhACs except naproxen (NAP). The fabricated sensor exhibited a remarkable sensing performance for detecting PhACs, which is promising for developing novel calix[4]arene-coated QCM sensors for PhACs.