Electronic tongue for simultaneous determination of cyanide, thiocyanate and iodide

Five cross selective electrodes comprising cyanide, thiocyanate, and iodide coated graphite electrodes CGEs were used as sensing parts of an electronic tongue for simultaneous determination of cyanide, thiocyanate, and iodide ions in the presence and the absence of chloride ion as a coexisting ion. The CGEs were constructed using poly(vinyl chloride) (PVC), o-nitrophenyl octyl ether (o-NPOE), cetyltrimethylammonium bromide (CTAB), and metal-porphyrin complexes as ionophores. The constructed electrodes were characterized to obtain their calibration curve, response time, and repeatability. A programmed switching system combined with an array of the five potentiometric coated graphite electrodes (i.e., ion-selective or cross-selective electrodes) were connected directly to a pH/potentiometer and a computer to sequentially acquire the potential corresponding to water sample mixtures. The acquired potentials were recorded and saved on the computer and were used as input variables for an artificial neural network to simultaneously yield the concentrations of cyanide, thiocyanate and iodide ions in simple and complex mixtures. A feed-forward, back propagation network with a Levenburg-Maquart algorithm was employed to optimize the network parameters. (C) 2016 Elsevier Ltd. All rights reserved.