An electronic tongue for simultaneous determination of Ca2+, Mg2+, K+ and NH4+ in water samples by multivariate calibration methods

In this study, a multi ion-selective electrode system was developed for simultaneous determination of Ca2+, Mg2+, K+ and NH4+ ions. The system, called electronic tongue, was used for the quantitative determination of these ions in different water samples. The measurement system was comprised of sixteen ion-selective electrodes, an Ag/AgCl double-junction reference electrode, and a sixteen-channel multi-potentiometer. In the fabrication process of the electronic tongue, an electrode body, which comprised eight ion-selective electrodes together on it, was designed. The obtained data were evaluated by using multivariate calibration methods such as Classical Least Squares (CLS), Principal Component Regression (PCR) and Partial Least Squares (PLS1). The parameters that influence the electronic tongue performance were investigated. Analyses were conducted in synthetic water samples and real water samples. Percentage recovery values in synthetic samples, which were calculated via PLS1, were found 101.35%, 102.41%, 100.04% and 99.23% for Ca2+, Mg2+, K+ and NH4+ respectively. The results, obtained from the electronic tongue and other analytical techniques, were compared and no significant difference was found between the results at 95% confidence level.