An electrochemical sensor system with renewable copper modified electrode for continuous nitrate determination

An automatic electrochemical sensor system based on sequential injection analysis (SIA) technique for continuous nitrate determination is demonstrated. A three-electrode-system (Pt-Pt-Ag/AgCl), in which the Pt working-electrode was modified with renewable copper layer, is designed and fabricated to implement sensitive and reproducible nitrate detection under a programmed operation protocol. Based on an optimal potential protocol, the continuous renewal of copper sensing material was achieved on the working-electrode surface to ensure each measurement can be performed on a fresh and highly active copper surface, which guaranteed that automotive and continuous nitrate determination was achieved for a long period of time. The developed system was used to detect nitrate in real freshwater samples. The results were in good agreement with the data obtained by the standard ultraviolet spectrophotometric method for nitrate detection.