A novel thin film impedance Ca ion sensor for drinking water

•In our new approach, the calcium sensor system consists of an impedimetric conductivity sensor and impedimetric Ca ion-sensitive sensor.•A reference electrode is not required for impedimetric measurements, as is the case with potentiometric sensors.•By eliminating the membrane, conditioning lasts only a few minutes instead of hours. 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.