Smartphone-Based Device for Monitoring Chemical Pollutants in Water

There remains a need for a cost-effective, sensitive and on-site analytical technique which requires minimal technical skills for monitoring chemical contaminants in water. This research work presents a smartphone-based colorimetric detection of trace chemical pollutants in water. Components of the Hue, Saturation and Value (HSV) color space within a global region of interest (ROI) of analytes’ image were utilized in developing an algorithm for the quantitative detection of target ions. Calibrations were conducted with Chromium (VI) and Nitrite analytes ranging between 0–250 ppb and 0–3000 ppb respectively. The calibration equation and coefficient of correlation as obtained were HS2 = −0.00918C+6.46003; R2 = 0.9997 and HS2 = −0.00584C+4.85119; R2 = 0.98228 respectively. The smartphone-based monitoring system was utilized to systematically obtain the concentration of target ions in arbitrary solutions. Limits of detection of the system for Nitrite and Chromium (VI) which are within USEPA specification were approximately 285 ppb and 16 ppb respectively. Appreciable agreements between conventional and proposed techniques were obtained with a maximum percentage difference of 8.21% in the concentration of an arbitrary sample.