Rapid determination of volatile organics using a nanoporous zinc oxide microsphere-coated quartz crystal microbalance

The organic vapor sensing properties of nanoporous ZnO microspheres coated on a quartz crystal microbalance were characterized. The ZnO nanoparticles were aggregated by aqueous synthesis into micrometer diameter spheres. The porous structure of the microspheres provided sufficient surface area for vapor adsorption and diffusion for gas exchange. The reversible response suggests that complete desorption without contamination was achieved. Sensing films on a quartz crystal microbalance (QCM) were characterized using five volatile organic compounds with different functional groups to compare the differences in selectivity between polyisobutylene (PIB) and nanoporous ZnO. The response time for nanoporous ZnO was half the value of the PIB-coated sensor. The results show that nanoporous ZnO microspheres are an alternative that provide selectivity and rapid response for QCM.