Patent ID: 7930923
Filing Date: 2011-04-26
Classification: G01N

Abstract:
1. An indium tin oxide (ITO) quartz crystal microbalance (QCM) sensor system comprising: a quartz crystal with a pair of electrodes, said quartz crystal having a sensing surface and being configured for installation in and oscillation in a crystal holder, and said electrodes being configured for electrically coupling the quartz crystal to a crystal oscillator; a nanocrystalline ITO thin film formed as a sensing surface on said quartz crystal, said nanocrystalline ITO thin film comprising an adsorbent that attracts at least one gaseous compound emitted from an analyte; said system further comprising a means for oscillating the quartz crystal with the nanocrystalline ITO thin film formed thereon; a means for determining the frequency of oscillation of the quartz crystal with the nanocrystalline ITO thin film formed thereon; a means for determining surface resistance of the quartz crystal with the nanocrystalline ITO thin film formed thereon; a computing device configured for determining a parameter from the group consisting of integrated frequency response, integrated surface resistance response, initial response slope, average return to baseline slope, return to baseline time/initial response time ratio, and average change in frequency for the quartz crystal with the nanocrystalline ITO thin film formed thereon; and a principal component analysis means for determining principal components for the at least one gaseous compound.