Smartphone-Based Photometric Detection of Nitrite Level in Water

This work demonstrates an affordable, field-portable smartphone-based sensing tool for estimation of nitrite in water medium. The sensing principle is based on the well-known Beer-Lambert principle where transmitted modulated signal from the sample is captured by the ambient light sensor (ALS) of the phone and correlates its signal intensities with the concentration of nitrite present in the samples. The results obtained with the smartphone sensor is found to be agreed well with the laboratory-grade spectrophotometer.