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 potentiometric cells. Combinations of a poly(vinyl chloride) (PVC) matrix nitrate ion-selective electrode with inner filling solution, a solid contact PVC nitrate electrode, a capillary flow type reference electrode, and a solid state reference electrode were tested. A linear increase of the potentials as a function of pressure was observed in all cases after an initially non-linear phase. The overall potential changes in the investigated pressure range were between 0.2 mV and 1.5 mV, slopes being typically 10 μV bar−1 and 40 μV bar−1 for nitrate electrodes with liquid filling solutions and for solid contact nitrate electrodes, respectively.