ABSTRACT

For the optimalization of conditions during the development of an analytical method based on Potentiometric detection, the most important characteristics of the Potentiometrie sensors must be considered, among which the dynamic properties of the sensors are of utmost importance. With the aim of increasing the rate and precision of measurements in continuous flow systems based on neutral carrier ion-selective electrodes (ISE), Morf and Simon and Deutsch and others suggested a method for determining the steady-state potential from the rising part of a dynamic response curve by the use of an appropriate mathematical equation and extrapolation by nonlinear regression analysis. This method is of utmost importance if the final value of the steady-state electrode potential is approached slowly. In complete agreement with the theoretical expectations relevant to the dynamic response characteristics of the sensors in the two-ion range, asymmetric potential peaks are often reported in the literature by injecting samples of high interfering ion activity.