Wireless water quality monitoring and spatial mapping with disposable whole-copper electrochemical sensors and a smartphone

Portable, rapid, and cost-effective detection of environmental contamination remains an important challenge in the field of water quality analysis. Herein, we described a smartphone-based water quality monitoring system that allowed for the quantification of Pb 2+ ions and chemical oxygen demand (COD) at an exact location. The system was composed of four main parts: (i) a whole-copper electrochemical sensor, (ii) a hand-held detector, (iii) a smartphone installed with a custom application program, and (iv) a Cloud map website. The sensor chips were made of low-cost copper, including microfabricated Cu working electrodes, Cu counter electrodes, and Cu/CuCl 2 reference electrodes. The hand-held detector (∼50 g) can perform several types of electroanalytical techniques, including chronoamperometry, cyclic voltammetry, linear sweep voltammetry, and square wave voltammetry. With an Application (App), the smartphone was used to control the detector and visualize the testing results in real time. A Cloud map website was used to receive and display the contamination concentrations and geographic locations for public sharing and viewing. Since the smartphone-based system is cost-effective, small in size, field-portable, and fully wireless, it shows great potential for applications in resource-limited settings.