Method for the automated in situ determination of an analyte content of a liquid sample using a bioanalyzer comprising a microfluidic unit with at least one measuring channel and means for conducting one or more liquids through the measuring channel, wherein the measuring channel has at least one electrically conductive substrate, said method comprising the following sequence of steps, which can be performed repeatedly, to measure at least within a measuring region: (i) preparation of a sensor matrix, which has a plurality of receptors that bind the analyte and/or an additional target molecule, preferably selectively and specifically, particularly due to an affinity interaction, or bring about the chemical conversion of the analyte or the additional target molecule, comprising a step wherein a preparation solution of at least a first chemical species, which comprises at least one functional group binding to the substrate and at least one other functional group, is conducted through the measuring channel, wherein a plurality of the first chemical species is bound to the substrate via the functional group binding to the substrate, wherein the additional functional groups of the plurality of the first chemical species bound to the substrate act as receptors; (ii) the conduction of the liquid sample, or a liquid under measurement obtained by treating the liquid sample with at least one reagent, through the measuring channel, wherein the analyte contained in the liquid sample or in the liquid under measurement, and/or other target molecules contained in the liquid sample or in the liquid under measurement, bind to the receptors, preferably selectively and specifically, or are converted chemically by said receptors, and the determination of a measured variable, which correlates to the amount of the target molecules bound or converted by the receptors, or the amount of analyte bound or converted by the receptors, and derivation of the analyte content of the liquid sample on the basis of said measured variable; (iii) clearing of the at least one substrate, wherein the sensor matrix and, where applicable, molecules bound thereto, particularly analyte molecules, additional target molecules or other molecules, are released from the substrate and at least partially decomposed, wherein the substrate is cleared by continuously passing an electrolyte through the measuring channel and generating an electrical flow of current between the substrate and a counter-electrode which is in contact with the substrate in an electrically conductive manner via the electrolyte in order to clear the substrate, wherein, while the electrolyte is passed through the measuring channel, the potential of the substrate varies between negative values in the range between -0.5 V and -1.25 V and positive values in the range between +1.5 V and +2.25 V in relation to an Ag/AgCl reference electrode such that the sensor matrix is alternately exposed to oxidative and reductive conditions and resulting hydrogen or oxygen. (i) preparation of a sensor matrix, which has a plurality of receptors that bind the analyte and/or an additional target molecule, preferably selectively and specifically, particularly due to an affinity interaction, or bring about the chemical conversion of the analyte or the additional target molecule, comprising a step wherein a preparation solution of at least a first chemical species, which comprises at least one functional group binding to the substrate and at least one other functional group, is conducted through the measuring channel, wherein a plurality of the first chemical species is bound to the substrate via the functional group binding to the substrate, wherein the additional functional groups of the plurality of the first chemical species bound to the substrate act as receptors; (ii) the conduction of the liquid sample, or a liquid under measurement obtained by treating the liquid sample with at least one reagent, through the measuring channel, wherein the analyte contained in the liquid sample or in the liquid under measurement, and/or other target molecules contained in the liquid sample or in the liquid under measurement, bind to the receptors, preferably selectively and specifically, or are converted chemically by said receptors, and the determination of a measured variable, which correlates to the amount of the target molecules bound or converted by the receptors, or the amount of analyte bound or converted by the receptors, and derivation of the analyte content of the liquid sample on the basis of said measured variable; (iii) clearing of the at least one substrate, wherein the sensor matrix and, where applicable, molecules bound thereto, particularly analyte molecules, additional target molecules or other molecules, are released from the substrate and at least partially decomposed,