Piezoelectric resonance sensor for the determination of ammonium in aqueous environment

Abstract

In this study, a novel ammonium biosensor based on quartz crystal microbalance QCM system for determination of ammonium ion, a reaction product of urea by urease was described. Piezoelectric quartz crystals were coated with poly lactic-co-glycolic acid PLGA; 85:15 nanofiber containing fullerene C60. Then, urease EC 3.5.1.5 was immobilized on nanofibrous electrospun PLGA membrane. The nanofibers were characterized using scanning electron microscopy. Changes in the resonance frequency of the PLGA/C60–coated quartz crystal were evaluated as an indicator of changes in urea concentration. The oscillating frequency decreased accordingly to the deposition of ammonium on the quartz crystal surface. Our results indicate that the PLGA/C60 nanofiber coated piezoelectric sensor exhibited ability to determine the ammonium ion in the solution