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-PLS2) 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 29.8μM for Cd 2+ , 0.05μM to 1.5μM for Cu 2+ and 0.55μM to 14.7μM for Pb 2+ . Potentiometric recordings were arranged into a three-way array and treated by N-PLS2 regression method to obtain the calibration model. Prediction ability yielded RMSE values as low as 4.20±0.37μM, 0.094±0.007μM and 0.915±0.006μM, 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. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.