Electronic tongues

The use of multivariate data analysis combined with sensors with partially overlapping selectivities has become a very powerful tool in measurement technology. These systems are often referred to as artificial senses, because they function in a way similar to the human senses. One such system is the electronic nose. This article focuses on similar concepts as the electronic nose, but for use in aqueous solutions. Because these systems are related to the human sense of taste in the same way the electronic nose is related to olfaction, they have been termed taste sensors, or "electronic tongues." Various measurement principles that can be used in electronic tongues are described and discussed in this article, These include electrochemical techniques such as potentiometry, voltammetry, and conductometry. Also, optical techniques based on light absorption at specific wavelengths or the use of surface plasmon resonance are described. Mass-sensitive devices based on piezoelectric crystals have also been used and are described here. A special emphasis is given to the voltammetric electronic tongue.