Patent ID: 7785457

Claim:
A sensor element of a gas sensor for determining a concentration of ammonia in a gas mixture, comprising: at least one first auxiliary electrode situated in a first measuring gas compartment; at least one measuring electrode situated in the first measuring gas compartment, a signal generated by the at least one measuring electrode being used at least intermittently to determine the concentration of ammonia; at least one further first auxiliary electrode situated in a second measuring gas compartment; and at least one further measuring electrode situated in the second measuring gas compartment, a signal generated by the at least one further measuring electrode being used at least intermittently to determine the sum of the concentration of ammonia and nitrogen oxides; wherein: the electrodes are positioned downstream in the flow direction of the gas mixture, which are in direct contact with the gas mixture, and a potential, at which the ammonia contained in the gas mixture is oxidized, is applied at least intermittently to one of the first auxiliary electrode and the at least one measuring electrode and one of the further first auxiliary electrode and the at least one further measuring electrode.