Electrochemical impedimetric sensing of nitrate contamination in water

Abstract

This paper describes the design and development of a sensing system to detect the nitrate concentration by using planar interdigital sensor immersed in the water sample. Water samples were prepared containing two different salts: Sodium Nitrate (NaNO 3 ) and Ammonium Nitrate (NH 4 NO 3 ) with the concentration ranging from 0.02 PPM to 10 PPM by using the serial dilution method. The water sample was tested by both the commercial equipment (LCR meter) and designed system. Although a difference was observed between these two results, the designed system shows a good linear relationship between the low concentration (0.02 -0.5 PPM) of the water solution and the real part of the impedance. However, the relationship was changed from linear to logarithmic scale at the high concentration (0.05 -10 PPM) of the water solution. The computational formula of concentration was formed from these results. This system has a potential to be used in-situ nitrate contamination detection with real-time monitoring.