Abstract: This study demonstrates the promising steps towards improving the detection of small analytes in an aqueous solution by the quartz crystal microbalance (QCM) modified with a molecularly imprinted polymer (MIP) based sensitive layer. A homogeneous thin polymer film of poly(m-phenylenediamine) (PmPD) was electrochemically deposited on the surface of a QCM sensor in the presence of sulphamethizole (SMZ) acting as a template molecule. The binding capacity of the resulting SMZ–MIP films was enhanced by modifying the sensing surface with a diethylaminoethyl-dextran (DEAE-Dex) layer, forming a SMZ–MIP(Dex) film. The dextran layer allows further preconcentration of template molecules on the sensor electrode before polymer electrodeposition. The relative adsorption of the SMZ–MIP(Dex) films, as designated by the imprinting factors, was found to be in all cases significantly higher than that of the other films. At least about three times enhanced relative binding capacity of the modified imprinted polymer on the QCM sensor was established. A probe of the analysed sensor signals revealed that the modification steps significantly reduced the contribution from nonspecific interaction of the polymer matrix, thus suggesting beneficial effects of the dextran modification and template preconcentration. The presented approach promises a positive route towards an improved specific detection of small molecules by molecular imprinting on QCM sensor transducers.
Template and target information: sulphamethizole, SMZ
Author keywords: molecularly imprinted polymer, small molecule detection, sulphamethizole, quartz crystal microbalance, DEAE-dextran