What is that?
The electronic nose is a tool that emulates the functionality of the human nose. The instrument is made up of a series of sensors, each with different responses to volatile molecules and an appropriate recognition system that allows for the identification of simple and complex odours. Of these devices, often referred to as IOMS (Intrumental Odor Monitoring System), there are several. Some are commercial products, others prototypes born in universities and industrial laboratories. In recent years they have been evolving rapidly thanks to the development of technologies related to Artificial Intelligence.
Electronic nose architecture
As in common computers, in electronic noses we can distinguish a hardware part and a software part. The physical part consists of an air pumping system that arrives in a cell where several sensors are housed. The most used sensors are the so-called MOS (metal oxide sensors) but specific electrochemical sensors (EC) are also used for single pollutants such as ammonia and hydrogen sulphide and photoionization sensors (PID) specific for unsaturated compounds (aromatic hydrocarbons, olefins, carbonyl compounds ). The software part is the odor recognition code starting from the imprint made up of the signals produced and converted into digital by the series of sensors present. In recent years this part is implemented using the new artificial intelligence resources such as machine learning and neural networks. Also for this reason that the electronic nose requires an initial calibration, the so-called training, for the recognition of the different odor sources present in the area of use of the device.
Applications of the electronic nose
The typical applications of the electronic nose are the quality control of food products by detecting any adulteration and alterations and in medicine the diagnosis by examination of biological fluids. Unlike the human nose, electronic noses are less powerful but provide an objective response. By improving the sensor matrix and the recognition code, the performance of these digital devices will soon be comparable if not superior to that of natural olfactory systems.