Array of sensors based on lanthanide bisphtahlocyanine Langmuir-Blodgett films for the detection of olive oil aroma

In this paper a sensor array based on Langmuir-Blodgett (LB) films of lanthanide bisphthalocyanines (LnPc(2)) aiming to discriminate among diverse virgin olive oils has been designed. For this purpose, sensors based on bisphthalocyanines including unsubstituted bisphthalocyanines with different central metal atom (PrPc2 and LuPc2) and a octatertbutyl substituted bisphthalocyanine (PrPc2') have been prepared. The interaction of the sensors with the headspace of olive oil samples has been studied by registering the changes in the conductivity produced in the LB films, The influence in the response of parameters such as the number of monolayers or the proportion of arachidic acid used in the preparation of the LB films has been analysed. Studies on the stability and reproducibility of the LB film-based sensors have been carried out. Using the previous results, the sensors with the best performance characteristics have been selected, and an array of five sensors has been constructed. The array has been exposed to four types of Spanish olive oils with different organoleptic properties and qualities. The principal component analysis of the obtained signals has allowed the discrimination of the different types of olive oils. (C) 2001 Elsevier Science B.V. All rights reserved.