The electronic nose was developed in order to mimic human olfaction that functions as a non-separative mechanism: i.e. an odor / flavor is perceived as a global fingerprint. Essentially the instrument consists of head space sampling, sensor array, and pattern recognition modules, to generate signal pattern that are used for characterizing odors.
Electronic noses include three major parts: a sample delivery system, a detection system, a computing system.
The sample delivery system enables the generation of the headspace (volatile compounds) of a sample, which is the fraction analyzed. The system then injects this headspace into the detection system of the electronic nose. The sample delivery system is essential to guarantee constant operating conditions.
The detection system, which consists of a sensor set, is the "reactive" part of the instrument. When in contact with volatile compounds, the sensors react, which means they experience a change of electrical properties.
In most electronic noses, each sensor is sensitive to all volatile molecules but each in their specific way.

License information: CC BY-SA 3.0
MPAA: G
Go to source: https://en.wikipedia.org/wiki/Electronic_nose