| abstract |
(A) The determn. of an analyte (I) comprises electrochemical reaction in the presence of an oxido-reductase (II) and a reducible substance (III) which, in the course of the reaction, transfers electrons from (II) to an electrode, thus giving rise to a signal which is a measure of (I). (III) is enzymatically reduced. Oxidn. occurs on the electrode, with the substance produced by this oxidn. being different from the original (III). (B) A substance which is capable of taking up electrons from a (II) to form an electron-rich aromatic amine can be used as an electron carrier between a (II) and an electrode in an electrochemical system. (C) A sensor electrode system for the electrochemical determn. of (I) in which a sample contains at least 2 electrically conducting agents which are isolated from each other and which are each brought into electrical contact with the sample (I) via an electrically conducting surface, so that at least one of these surfaces is in contact with a (II) and a (III) which is capable of transferring electrons between the (II) and the surface. The (III) used is a cpd. which, after redn. by (II) can be oxidised on the surface to give a substance different to the original (III). |