Visual artificial tongue for identification of various metal ions in mixtures and real water samples: a colorimetric sensor array using off-the-shelf dyes

Abstract

A three-unit colorimetric sensor array in aim of detecting heavy metal ions has been constructed with two off-the-shelf dyes. Multivariate data analysis is performed using LDA and HCA to recognize colour change patterns based on both absorption spectra and RGB values from image scans. The sensor array is able to differentiate 15 metal ions not only in separate solutions, but also mixtures of 3, 5, and 7 different metal ions and real water samples.