A hybrid electronic tongue

A hybrid electronic tongue is described based on a combination of potentiom etry, voltammetry and conductivity. It was used for classification of six d ifferent types of fermented milk. Using ion-selective electrodes, pH, carbo n dioxide and chloride ion concentrations were measured. The voltammetric e lectronic tongue consisted of six working electrodes of different metals (g old, iridium, palladium, platinum, rhenium and rhodium) and an Ag/AgCl refe rence electrode. The measurement principle is based on pulse voltammetry in which current transients are measured due to the onset of voltage pulses a t decreasing potentials. The data obtained from the measurements were treat ed by multivariate data processing based on principal components analysis a nd an artificial neural net. The hybrid tongue could separate all six sampl es. Also, the nature of the micro-organisms in the different fermentations was reflected in the principal component analysis. (C) 2000 Elsevier Scienc e B.V. All rights reserved.