Low-cost online determination of calcium-magnesium-ratio by cyclic voltammetry

The determination of ion shares is important for water quality analysis. Most of these analysis are carried out by optical methods or selective probes. Such methods are precise but expensive and mostly not suitable for online measurements because complex devices or chemical substances are needed. The Ca/Mg-ratio is a very important parameter for cleaning equipment like washing machines or dish washers. Calcium and magnesium ions are very similar and can not be distinguished by impedance spectroscopy. This work discuss a measurement method based on cyclic voltammetry to determine the calcium-magnesium-ratio in water. This method can be implemented easily in a sensor system for low-cost online measurement applications to determine ion shares in liquid solutions.