Fully Integrated, Simple, and Low-Cost Electrochemical Sensor Array for in Situ Water Quality Monitoring

Rapid, accurate and inexpensive monitoring of water quality parameters is indispensable for continued water safety, especially in resource-limited areas. Most conventional sensing systems either can only monitor one parameter at a time or lack user-friendly on-site monitoring capabilities. A fully integrated electrochemical sensor array is an excellent solution to this barrier. Electrochemical sensing methods involve transduction of water quality parameters where chemical interactions are converted to electrical signals. The challenge remains in designing low-cost, easy-to-use, and highly sensitive sensor array that can continuously monitor major water quality parameters such as pH, free chlorine, temperature along with emerging pharmaceutical contaminants, and heavy metal without the use of expensive laboratory-based techniques and trained personnel. Here, we overcame this challenge through realizing a fully integrated electrochemical sensing system that offers simultaneous monitoring of pH (57.5 mV/pH), free chlorine (186 nA/ppm), and temperature (16.9 mV/°C) and on-demand monitoring of acetaminophen and 17β-estradiol (