Abstract: A device for the electrochemical detection of at least one biochemical molecule contained in a liquid from a group of predetermined biochemical molecules includes a holder (1) for taking up the liquid, with at least one reference electrode (RE) and at least one counterelectrode (GE) and a multiplicity of working electrodes (AE1, AE2, AE3). At least one working electrode is provided for the detection of each biochemical molecule, and is coated with a molecule that is complementary to the respective biochemical molecule, so that the biochemical molecules can be detected simultaneously. The device includes a potentiostat (P) for generating a predetermined voltage profile between the working electrodes and the reference electrode, a current/voltage converter (S1, S2, S3) connected downstream of each of the working electrodes for holding all of the working electrodes at the same potential, and a measurement device (Ad) for measuring the currents flowing through the working electrodes.

Abstract: The present invention provides a marking solution that is to a certain extent counterfeit-resistant, that is particularly easy to use, that can be stamped and that can be used for performing day-to-day markings, especially for the identification of documents, and that is suitable for comparatively simple identification. The marking solution includes an aqueous solution with single-stranded nucleic acids or derivatives thereof, in addition to glycerin and polyethylene glycol (PEG).