Porphyrin-based array of cross-selective electrodes for analysis of liquid samples

The development of artificial taste systems although devised since two decades has been hampered by the difficulties to find a material easily modifiable to form arrays of non-selective sensors endowed with sufficient cross-selectivities. On the other hand, materials with such features have been extensively studied for artificial olfaction systems. In particular, metalloporphyrins revealed interesting properties making them suitable for electronic nose development. In this paper, an investigation of the properties of glassy carbon electrodes modified with electropolymerised porphyrins is carried out. In particular, the study of the porphyrin structure to sensitivity relationship has been approached. Results confirm the behaviour observed with porphyrin-based gas sensors, namely the important role played by the metal atom in determining the sensor performances. An array of five glassy carbon modified electrodes was tested in a sample experiment aimed at discriminating among five compounds each belonging to a different basic taste class. Results shows that the taste discrimination is positively carried out for concentrations down to 10(-6) M. Obtained results are a reasonable basis to devise the development of artificial taste systems for a wide range of practical applications. (C) 2003 Published by Elsevier B.V.