Prototype development of paper based sensor for ammonia detection in water

Abstract

The presence of ammonia in water supply can be harmful to human health. The ammonia is colorless, thus its presence not easily detected. Therefore, a suitable sensor for this detection is necessary. The sensor device developed in this study was utilizing bio-environmental friendly materials such as paper and graphite. Several combination of paper and graphite type were used to evaluate the sensitivity and selectivity of sensor. A suitable device pattern was defined as the sensing area for detecting the presence of ammonia in water. The device was connected with a constant voltage to generate the current flow between electrodes made of graphite and the liquid sample was tested by drop it onto the sensing area. As the result, the significant current changes could be detected with presence of ammonia in deionized (DI) water at different concentration level. A zinc oxide layer was proposed to be added at the sensing area for sensing enhancement. Based on the sensing response, the presence of zinc oxide demonstrated improvement on device sensitivity by displaying faster response characteristics. Thus, the combination of graphite and zinc oxide at sensing area is recommended where it able to better distinguish the level of ammonia concentration compared to those sensing area without zinc oxide. Besides low in cost, this biodegradable ammonia sensor prototype is considered safe and easy to be used by normal consumer for monitoring water quality.