Cost-Effective, Wireless, Portable Device for Estimation of Hexavalent Chromium, Fluoride, and Iron in Drinking Water

The quality of drinking water often remains unknown to people because of the inadequacy of cost-effective testing systems that can be used in the field. Major portable instruments for water-quality analysis include ion-selective electrodes (ISE) or colorimeters. These are low-cost devices, but in the case of multiple-analyte detection, such as that of hexavalent chromium (Cr), fluoride (F-), and iron (Fe), with a single instrument, no portable systems are available, to the authors' knowledge. In this paper, we demonstrate the use of a low-cost (approximate price of INR 1500 or US$20), portable colorimetric system that can be operated with Android smartphones wirelessly to estimate the contamination levels of Cr(VI), F-, and Fe in drinking water. This system also generates absorption spectra by recording the absorbance of the analyte using a light-dependent-resistor (LDR) sensor. An Android-application software named Spectruino was developed to calculate the concentrations of the analytes. We strongly believe that this cost-effective, portable system will be very useful in improving human health by ensuring drinking-water quality throughout India.