Detection of Water Pollutant Using Surface-Polarity Controlled Sensor

Aldehyde and carboxylic acid compounds are known as volatile substances with bad smell. It is also said to cause bad smell of tap water. In this study, we tried to detect and analyse aldehyde and carboxylic acid dissolved in water, using a surface-polarity controlled sensor. The sensor measures electrochemical impedance of the electrode surface whose electric potential is dynamically controlled. Adsorption and desorption of target chemicals cause changes in impedance which has constant phase element (CPE) characteristics. The impedance changes depending on the electrode potential are used as a chemical sensor output. As a result, we could detect and distinguish many kinds of aldehyde and carboxylic acids. Furthermore various water pollutant can be detected with high sensitivity. The results suggest that a simple and multi-purposed sensor can be constructed for environmental analysis using the proposed method.