A novel thin film impedance Ca ion sensor for drinking water

This paper presents a miniaturized calcium ion-selective solid-state impedance sensor which can be used to measure Ca²⁺in the presence of Mg²⁺and Na⁺. A novel approach consisting of an ionophore-based Ca sensor combined with a conductivity sensor is used to take one of a wide variety of physical and chemical measurements in potable water. The sensors permit a relatively fast conditioning time. Their design and performance are described. The sensors utilize electrochemical impedance spectroscopy. The advantages are miniaturization and the potential for large-scale production.