A temperature-compensated graphene sensor for nitrate monitoring in real-time application

Low-cost nitrate-N sensors and smart sensing systems are necessary to develop a distributed network to monitor the quality of water in real time. This paper presents the fabrication process of carbon printed sensors and the advantage of using a graphene sensor to measure the concentration of nitrate-N in water. The sensor was characterized at different temperatures and with different nitrate-N concentrations in water. Electrochemical Impedance Spectroscopy (EIS) was employed to characterize the developed sensors. The calibration standard with the temperature compensation is also explained. UV-Spectrometry was used to validate all the results and the range of concentrations was 1-70 ppm. The sensing system has WiFi connectivity to transfer the data to a cloud server to monitor the data in real time. The sensor has shown good performance during measurements and the developed sensing system has very good potential to be a part of a distributed sensing network to monitor the data in real time.