Interfering substances in a solution to be examined can falsify the measurement results of an electrode sensor in the case of an amperometric method. In the case of a potentiometric relaxation measurement method, this falsification of the measurement results can be avoided by operating two similar electrode sensors, only one of which is provided with an enzyme. The analyte concentration which it is desired to ascertain is determined from the difference between the measurement results of the two electrode sensors. The method is suitable for long-term monitoring or control of analyte concentrations in medicine or biotechnology.
