EFFECT OF PRESSURE ON THE POTENTIOMETRIC RESPONSE OF ION-SELECTIVE ELECTRODES AND REFERENCE ELECTRODES

A study is presented on the influence of pressure of up to 30 bar on p otentiometric cells. Combinations of a poly(vinyl chloride) (PVC) matr ix nitrate ion-selective electrode with inner filling solution, a soli d contact PVC nitrate electrode, a capillary flow type reference elect rode, and a solid state reference electrode were tested. A linear incr ease of the potentials as a function of pressure was observed in all c ases after an initially non-linear phase. The overall potential change s in the investigated pressure range were between 0.2 mV and 1.5 mV, s lopes being typically 10 mu V bar(-1) and 40 mu V bar(-1) for nitrate electrodes with liquid filling solutions and for solid contact nitrate electrodes, respectively.