Abstract
This paper presents a compact and disposable electrochemical sensor which can be batch fabricated by standard microfabrication technology. The proposed sensor has the potential to be directly deployed for measuring water hardness, which is mainly contributed by dissolved calcium (Ca) and magnesium (Mg) ions. The analytical performance of the sensor is evaluated through electrochemical experiments. The experimental results indicate that the sensor is capable of detecting Ca and Mg ions down to 1 ppm with a linear detection range from 10 to 50 ppm.