Publication

Recently, it has been reported that detection of various ions from analytes such as biofluids and sea-water has a potential for medical diagnosis and environmental analysis. Especially, the measurement of calcium ions in water is one of the most important factors indicating the hardness and quality of water. A high concentration of calcium ions can be harmful to mineral circulation in natural environments and industrial applications [1]. Poly(3,4‐ethylenedioxythiophene)poly (styrenesulfonate) (PEDOT:PSS), conductive polymer, has drawn attraction for solid-contact material in various fields due to its unique properties. In recent studies on the electrochemical sensors, it has been reported that PEDOT:PSS not only enhances the electrode conductivity but also makes it strong resistance to O2 and CO2 owing to its low oxidation potential and bandgap [2]. Also, since PEDOT:PSS is well dispersed in water, it is easy to access as a solution process. Here, we demonstrate a facile fabrication method of calcium ion sensor for water quality monitoring. The printed carbon substrate electrode was modified by dropcasting aqueous dispersion of PEDOT:PSS and then coated with a calcium ionselective membrane. As a result, the fabricated sensor showed near-Nernstian response to dynamic concentration of calcium ions and negligible change to interfering ions. The proposed fabrication method can be promisingly applied to various potentiometric ion sensors capable of mass production at low-cost.