Ion-selective electrodes in their nonlinear, suboptimal response range

AbstractA method is presented that allows one to calculate changes in ion concentration from the response of an ion sensitive electrode, under conditions where the response of the electrode is nonlinear. In the calculations the response curve of the electrode is fitted with a polynomial function of the fourth power. Changes in the concentration of the probe-ion can be calculated with this polynomial. The calculation is based on a converging iteration procedure in which the concentration to be calculated is the zero value of the polynomial. The iteration procedure is run in Basic on a personal computer. This method extends the useful range of ion concentrations by more than one order of magnitude