Differential measuring using an ion exchanger applied to Ca2+ ion concentration determination

In this paper, differential measuring with chemical sensors is illustrated. The advantages of differential measuring are listed, followed by a practical example of such a chemical sensor system, consisting of a column filled with ion exchanger. The inlet and outlet of this column are provided with electrolyte conductivity (ec) sensors. Differential measuring of the electrolyte conductivity and the proper choice of the ion exchanger allows the absolute determination of specific ion concentration, present in the solution that passes the column. It is thus shown that Ca2+ ion concentrations in the mM range can be determined.