Quartz crystal microbalance with nanocrystalline oxide semiconductor thin films and method of detecting vapors and odors including alcoholic beverages, explosive materials and volatilized chemical compounds

Abstract

A nanocrystalline ITO thin film formed on a quartz crystal microbalance (QCM) facilitates detection of gaseous compounds emitted from an analyte. Adsorption of gas molecules onto the nanocrystalline ITO thin film changes the resonant frequency of the quartz crystal. Parameters such as the frequency of oscillation, surface resistance, integrated frequency response, integrated surface resistance response, initial response slope, average return to baseline slope, and/or return to baseline time/initial response time ratio of the quartz crystal with the nanocrystalline ITO thin film formed thereon are determined. Using the determined parameters and principal component analysis, principal components for the gaseous compounds are also determined. These determined principal components may be compared with known principal components corresponding to known analytes. The analyte may include any distinguishable substance, in any state that emits at least one gaseous compound that can be adsorbed on the nanocrystalline ITO thin film. Nonlimiting examples of analytes include alcoholic beverages, fruits, explosive compounds, VOCs, petroleum-based fuels, alkanes, aldehydes and ketones.