Electronic Tongue for Qualitative Analysis of Aqueous Solutions of Salts Using Thick-film Technology and Metal Electrodes

Abstract: An electronic tongue for the qualitative analysis of aqueous solutions of salts hasbeen developed. The following set of electrodes was used: RuO₂, Ag, and Cu in thick-filmtechnology and Au, Pb, Zn and Ni as small bars of the corresponding metal. The response ofthe designed “electronic tongue” was tested on a family of samples containing pure salt andcomplex mixtures. The electrodes were used as potentiometric un-specific sensors and thee.m.f. of each electrode in contact with a certain aqueous solution was used as input signalfor a PCA analysis. The study showed that the set of electrodes were capable to discriminatebetween aqueous solutions of salts basically by their different content in anions and cations(the anions SO4^2-, Cl^-, PO₄H^2-, CO₃H^-, NO^3- and cations Na⁺ and K⁺ were studied). In orderto better analyze the basis for the discrimination power shown by the electronic tongue, aquantitative analysis was also envisaged. A fair estimation of the concentrations of thedifferent ions in the solutions studied appeared to be possible using this electronic tonguedesign.Keywords: