Electrolyte concentration measuring device and method for obtaining selectivity coefficient

An electrolyte concentration measuring device for measuring an ion concentration of an analyte ion contained in a liquid, the electrolyte concentration measuring device comprising:

• an ion selective electrode configured to react with the analyte ion and output a potential corresponding to the ion concentration;
• a reference electrode configured to output a reference potential serving as a reference for the potential;
• and
• a control unit configured to output the ion concentration of the analyte ion based on a potential difference between the reference electrode and the ion selective electrode, wherein
• the control unit obtains a selectivity coefficient of an interfering ion that influences measurement of a concentration of the analyte ion or a value corresponding to a concentration of the interfering ion from a calculation unit by inputting, into the calculation unit, measured potentials of a plurality of solutions that contain the analyte ion and the interfering ion and have a same concentration of the interfering ion and different concentrations of the analyte ion, the calculation unit being trained to output the selectivity coefficient of the interfering ion or the value corresponding to the concentration of the interfering ion based on the measured potentials of the plurality of solutions that contain the analyte ion and the interfering ion and have the same concentration of the interfering ion and different concentrations of the analyte ion.