Electronic noses detect and identify odors and flavors. These devices can sense the underlying chemical makeup of an odor, each of which has a recognizable fingerprint, and also determine the presence of VOCs or contaminants. However, this quantitative analysis does not portray a sample's specific odor, as there are other variables beyond particle concentration to be considered, and the olfactory sense is subjective amongst individuals.
The sensing technology encompasses:
- Metal-oxide-semiconductor field-effect transistor (MOFSET): charged odor molecules are perceived by the electric field of the MOFSET, which is amplified and fed to a processor to recognize the electric signal.
- Intrinsically conducting polymers (ICPs): organic polymers with good electrical conductivity, which act as semiconductors.
- Polymer composites: resistive polymers with a conductive filler or additive.
- Quartz crystal microbalance (QCM): the acoustic resonance changes when a gas leaves any mass on the surface of the crystal.
Surface acoustic wave (SAW): frequency modulations are detected and referenced, which occur when passing through any particulate.