A novel, rapid and on-site determination of ionic concentration of methyl orange dye in aqueous solution using smartphone-based colorimetric sensor

Rapid and effortless detection of concentration of chemicals is of great significance in many chemical, biochemical laboratories, including pharmaceutical, and food industries. The recent technological advancement pushes the scientists to think and develop addon gadgets on smartphones for such applications. In view of that, we report a novel, portable, cost-effective analytical system for quantifying concentration of methyl orange dye in aqueous solution using smartphone-based colorimetric sensor module for rapid and on-site detection. Methyl orange (MO) dye as colorimetric agent was used to prepare 22 target samples in aqueous solutions. A background light source of uniform illumination was implemented as detection source. The rear camera of the smartphone was used as transducer. ‘Color Grab’ an open-source android application was employed to obtain colorimetric analysis of the target solutions by estimating the hue values. The working principle of this sensor module is based on Beer-Lambert law. The proposed method shows promising results for detection of concentration variation in terms of hue values. The detection limit was found to be 0.132 mg/l and limit of quantification was 0.4404 mg/l which can be treated as very much effective in case of trace level analysis.