3. Electronic Tongue Systems for the Analysis of Beverages

Desire to model, replace and improve human olfactory and taste systems drove scientists to develop new sensor arrays for gaseous and liquid samples. Design of those devices resembles biological recognition systems in which arrays of non-specific sensors present in the tongue or nose are used to gather information. This complex data is later processed and analyzed in the brain which provides decision about the sample (recognition, identification or quantification). Instead of brain, arrays of chemical sensors use methods of artificial intelligence and chemometry. In this study potentiometric sensors were chosen, as this technique is simple, low cost and does not require sophisticated equipment thus being consistent with the ideology of paper-based sensors. Development of an integrated system, with miniaturized reference electrode and using a minimum amount of sample was divided in three steps, each of them ending with a proof of concept application of proposed advances. First, individual, potentiometric, paper-based sensors were developed and used to discriminate forged water samples. In the next step an integrated Ag/AgCl reference electrode was introduced in the system which was used to classify 34 different beers. Last but not least, efforts were made to minimize sample volume and the final device was applied to discriminate 11 wine types.