Chemical Images of Liquids

Following the success of electronic noses in a variety of applications related to many areas such as industrial, medical, environmental, spatial, etc. where the objective was to construct chemical images of volatile compounds including odors, here we introduce another system able to perform chemical images of liquids of different origin, quality, and composition. In line with mammalian senses such as olfaction or taste, recently a strategy which applies the sensors not specific in character for a single analyte but rather broadly sensitive with the only necessary characteristic and prerequisite to be different from each other in terms of their responses, has been developed. The sensors are grouped in a matrix and supported by a suitable pattern recognition analysis in order to generate a global response of the overall array. For liquid phase analysis such a system is called Electronic Tongue. This chapter describes in some detail the operating principle of the sensors forming the electronic tongue multisensor system, the matrix strategy, the most suitable data analysis adopted for the purpose, and a number of chemical images of different liquids including potable and waste waters, soft drinks, alcoholic beverages, clinical samples and some biological objects, taking into account the different components’ concentration distributions present in the tested samples.