Universal Analytical Framework Coupling Open-Source Platforms with Colorimetry for On-Site Water Quality Assessment

Various analytical methods for water quality monitoring have been standardized to date; however, implementation of these techniques necessitates considerable skill or expensive equipment, which impacts their use. In this study, a pragmatic strategy that employs an open-source Arduino platform coupled with visible-spectrum colorimetry for water quality assessment is proposed. Validation procedures demonstrate satisfactory application of the developed system to determine free residual chlorine (frCl) and ammonia–nitrogen (NH3–N) in collected water samples. The detection limits achieved, i.e., 0.04 and 0.03 mg L–1 for frCl and NH3–N, respectively, are considerably lower than the concentration levels recommended by regulations; thus, the proposed technique has sufficient detection capability for common use. Moreover, on-site water quality assessment can be achieved using a compact configuration, as the system weighs less than 100 g and is powered by a laptop. Remarkably, the system constructed in this study is more cost-effective than commercially available spectrophotometers, at approximately USD 35 per system.