Application of practical nitrate sensor based on electrochemical impedance spectroscopy

Nitrate is a naturally occurring ionic compound that is part of nature’s nitrogen cycle. Nitrates are readily lost to ground and surface water as a result of intensive agriculture, disposal of human and animal sewage and industrial wastes and the impact of elevated nitrate concentrations on water quality, has been identified as a critical issue facing New Zealand’s future. It is therefore, highly desirable to monitor water quality to facilitate regional councils and central governments to understand trends in concentrations and to develop a healthy water management policy. Presently, water quality managers follow the traditional measurement systems that involve physically sampling water from remote sites and laboratory-based testing. These methods are expensive, require trained people to analyze the data and produce a lot of chemical waste. Due to the time and labor required, surface samples are often only collected once per month and these risks missing significant trends in nitrate loss. Therefore, it is of utmost important to develop low-cost, robust embedded sensor nodes to detect the concentration of individual nutrients like nitrate and nitrite in surface and ground water. The interdigital capacitive sensor has been used to measure the different nitrate concentration. The sensor used to measure also the temperature and humidity of the samples. The results have shown that the sensor has high potential in a different application.