Multiway Processing of Data Generated with a Potentiometric Electronic Tongue in a SIA System

In this work a potentiometric electronic tongue based on an array of three Ion Selective Electrodes (ISEs) as sensor elements and multiway partial least squares (N‐PLS 2 ) regression method as processing tool has been developed for simultaneous quantification of Cd 2+ , Cu 2+ and Pb 2+ in aqueous solution mixtures. The sensor array was formed by two chalcogenide glass sensors selective to Cd 2+ and Cu 2+ plus one PVC membrane sensor selective to Pb 2+ . Preparation, measurement and injection of samples in a step profile were performed by an automated SIA system. Concentration range covered was 1.05 µM to 29.8 µM for Cd 2+ , 0.05 µM to 1.5 µM for Cu 2+ and 0.55 µM to 14.7 µM for Pb 2+ . Potentiometric recordings were arranged into a three‐way array and treated by N‐PLS 2 regression method to obtain the calibration model. Prediction ability yielded RMSE values as low as 4.20±0.37 µM, 0.094±0.007 µM and 0.915±0.006 µM, and correlation coefficients from linear regression analysis of 0.82±0.038, 0.97±0.005 and 0.97±0.004 for Cd 2+ , Cu 2+ and Pb 2+ , respectively.