Electronic tongue based on chemically modified electrodes and voltammetry for the detection of adulterations in wines

An electronic tongue based on chemically modified voltammetric electrodes is able to detect successfully model fraudulent red wines obtained by adding a range of forbidden adulterants (frequently used in wine industry to improve the organoleptic characteristics of wines) to a given wine sample.The sensor array consists in two families of sensors, one based on phthalocyanine-based carbon paste electrodes (CPEs) and a second one based on electrodes covered with conducting polypyrrole doped with a range of counterions. The electrochemical response of both families of electrodes is related to the ions and to the electroactive molecules present in the solution, being particularly sensitive to pH and antioxidants. The use of sensitive materials with different chemical properties allows obtaining complementary information that enhances the capability of discrimination of the system.Prediction models have been successfully used to estimate chemical parameters, such as alcoholic degree and acidity by means of partial least squares (PLS). The sensor array coupled with pattern recognition techniques is able to distinguish the adulterations on account of their chemical nature.