Sensor arrangement having capture molecules immobilized on any of three sensor electrodes, wherein molecules to be detected can hybridize with the capture molecules; a control circuit for applying a first electrical signal to a selected sensor electrode and simultaneously applying a second electrical signal to at least two of the other sensor electrodes; a detection device, wherein in a first operating state a reference liquid is introduced into the sensor arrangement and a reference value of an electrical signal is detected at the selected sensor electrode, and in a second operating state an analyte possibly having molecules to be detected is introduced into the sensor arrangement and a sensor value of the electrical signal is detected at the selected sensor electrode; and an evaluation circuit, which, on the basis of the reference value and the sensor value, determines whether a hybridization event has taken place at the selected sensor electrode.