| CPC G01N 27/4163 (2013.01) [A61B 5/082 (2013.01); A61B 5/4845 (2013.01); G01N 27/30 (2013.01); G01N 33/4972 (2013.01); A61B 2560/0223 (2013.01)] | 18 Claims | 

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               1. An electrochemical fuel cell for measuring ethanol in human breath, the electrochemical fuel cell comprising: 
            a first electrode; 
                a second electrode; 
                a third electrode, wherein 
                the first electrode is provided as a measuring electrode in a regular operating mode of the electrochemical fuel cell and as a measuring electrode or reference electrode in a maintenance mode of the electrochemical fuel cell, 
                  the second electrode is provided as a counterelectrode in the regular operating mode of the electrochemical fuel cell and as a measuring electrode or reference electrode in the maintenance mode of the electrochemical fuel cell, and 
                  the third electrode is provided as a counterelectrode in the maintenance mode of the electrochemical fuel cell; and 
                a control module operatively connected to the first electrode, to the second electrode and to the third electrode and configured to control the first electrode, the second electrode and the third electrode to operate the electrochemical fuel cell alternatively in the regular operating mode or in the maintenance mode, to set, in a first phase of the maintenance mode, a first potential of one of the first electrode and the second electrode operating as the measuring electrode relative to another one of the first electrode and the second electrode operating as the reference electrode, and to set, in a second phase of the maintenance mode, a second potential of the one of the first electrode and the second electrode operating as the measuring electrode relative to the another one of the first electrode and the second electrode operating as the reference electrode. 
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