Electrochemical sensor array made from bisphthalocyanine modified carbon paste electrodes for discrimination of red wines

A new sensor system devoted to the discrimination of red wines is presented. It consists of an array of electrochemical sensors made from carbon paste electrodes modified with three rare-earth bisphthalocyaninate compounds, including lutetium(III), gadolinium(III) and praseodymium(RI) bisphthalocyaninates. The sensor responses have been evaluated either by cyclic voltammetry or by square wave voltammetry, and demonstrate that such voltammetric sensors show a rich response when immersed in red wines. In addition, this response can be tuned by changing the central metal atom of the double-decker complexes, obtaining sensing units with high cross-selectivity. The sensor array is exposed to six Spanish red wines made from the same grape variety, prepared using a similar vinification method, but belonging to three different geographic origins and ageing stages. The voltammograms indicate that each sensing unit provides a particular response to each class of wine. Finally, the signals coming from each sensor are combined and the system's discrimination capability is evaluated by using principal component analysis (PCA), where a windowed slicing pre-processing method has been developed to capture the information throughout the global response. The PCA score plots of the obtained data show the discrimination of the tested wines with a good-quality performance. (C) 2004 Elsevier Ltd. All rights reserved.