A Low-Cost Video-Based Reflectometer for Selective Detection of Cu2+ Using Paper-Based Colorimetric Sensors

Abstract

This paper presents a low-cost reflectometer for selective detection of Cu 2+ . The reflectometer is based on an emission light source using five light-emitting diodes at different wavelengths and a detector using a webcam. The samples were prepared using a filter paper-based colorimetric sensor with ascorbic acid-based quinoxaline derivative. Video analysis using gray color intensity was used to perform both copper ion screening ( ) and quantification of Cu 2+ in spiked samples. In addition, a multivariate validation was performed. The system proved to be selective to Cu 2+ among the screened ions, and its quantification was performed using partial least square regressions. Good linearity (R 2 = 0.979, coefficient of determination), low root-mean-square error of prediction (RMSEP = 5.20 × 10 -3 mol L -1 ) and high recovery (93.39-128.64%) were achieved. This method has potential to be employed for rapid and selective determination of Cu 2+ in water using low-cost instrumentation.