Patent ID: 8858779

Claim:
A method for detecting a proportion of at least one gas species in a measurement gas space using at least one sensor element, the sensor element having at least one oxygen reduction pumping cell for concentration of the gas species, at least one pumping cell connected downstream of the oxygen reduction pumping cell, at least two pumping electrodes, and at least one gas-tight chamber, wherein at least one of the pumping electrodes may be exposed to gas from the measurement gas space which has been concentrated by the oxygen reduction pumping cell, at least a further one of the pumping electrodes is disposed in the gas-tight chamber, and at least one measuring electrode is disposed in the gas-tight chamber, the oxygen reduction pumping cell and the pumping cell being galvanically isolated by at least one isolator layer such that ion transport between the oxygen reduction pumping cell and the pumping cell is eliminated, the method comprising: carrying out an initialization phase, wherein in the initialization phase, a defined initial state in the gas-tight chamber is carried out by pumping; carrying out an accumulation phase, wherein in the accumulation phase, an accumulation of a quantity of oxygen in the gas-tight chamber is carried out by pumping via the pumping cell, the quantity of oxygen representing a measure of a proportion of the gas species in the measurement gas; and determining the proportion of the gas species from a potential variation of the measuring electrode.