Abstract: A gas measuring device (100) measures cyanogen in the presence of hydrogen cyanide. The gas measuring device (100) includes a measuring chamber (101), a heating element (103, 203) and an electrochemical sensor (105, 200). The measuring chamber (101) is configured to receive a sample. The heating element (103) is configured to thermally decompose cyanogen contained in the sample into decomposition products. The sensor (105, 200) is configured to detect the decomposition products of cyanogen, which are obtained by the thermal decomposition. A process measures cyanogen in the presence of hydrogen cyanide.

Abstract: An electrochemical fuel cell measures ethanol in human breath and a process maintains such an electrochemical fuel cell. The electrochemical fuel cell includes a first electrode (1), a second electrode (2) and a third electrode (3). The first electrode (1) is used as a measuring electrode in a regular operating mode of the electrochemical fuel cell and as a measuring electrode or as a reference electrode in a maintenance mode of the electrochemical fuel cell. The second electrode (2) is used as a counter electrode in the regular operating mode of the electrochemical fuel cell and as a measuring electrode or as a reference electrode in the maintenance mode of the electrochemical fuel cell. The third electrode (3) is used as a counter electrode in the maintenance mode of the electrochemical fuel cell.

Abstract: A gas sensor (1) with a detector element (2), which is specific to a gas to be measured and sends a measured signal that depends on the measured gas concentration, has increased measuring sensitivity for measurements in the concentration range from less than 1 ppb to a few ppb. The detector element (2) is exposed in a gas admission adapter (4) to a gas to be measured via a diaphragm (3) arranged in front of the detector element (2), wherein the gas admission adapter (4) has at least a first opening (20) for the entry of the gas to be measured as well as at least a second opening (30), which is connected with a pressure modulator, which generates periodic gas pressure vibrations in the gas admission adapter (4) and is designed, for example, as a pump (5).

Abstract: A gas sensor (1) with a detector element (2), which is specific of the gas to be measured and sends a measured signal that depends on the measured gas concentration, has increased measuring sensitivity for measurements in the concentration range from less than 1 ppb to a few ppb. The detector element (2) is exposed in a gas admission adapter (4) to a gas to be measured via a diaphragm (3) arranged in front of it, wherein the gas admission adapter (4) has at least a first opening (20) for the entry of the gas to be measured as well as at least a second opening (30), which is connected with a pressure modulator, which generates periodic gas pressure vibrations in the gas admission adapter (4) and is designed, for example, as a pump (5).

Abstract: An electrochemical measuring cell for the simultaneous detection of different gas components in a gas sample, with a plurality of measuring electrodes (4, 5, 6) behind a diffusion barrier (7), with a common reference electrode (8) and counterelectrode (9) in an acid electrolyte, and with a potentiostatic evaluating circuit. Improvements in terms of service life for a sensor for the simultaneous detection of oxygen and carbon monoxide is provided with a reference electrode formed of a sintered mixture of metal and its metal oxide, preferably from the platinum group, the iridium group or gold and the potential of the CO-measuring electrode (5) relative to the reference electrode (8) is set at about 0 to 300 mV, and that of the O.sub.2 -measuring electrode (4) is set at a value between -300 and -800 mV.

Abstract: The invention is directed to an electrochemical cell for measuring ammonia, amines, hydrazine and hydrazine derivatives and includes a measuring electrode in an electrolyte. The measuring electrode is provided with a coating made of a transition metal oxide and is improved in that its measuring sensitivity during long-term loading is increased. The cross sensitivity of the measuring cell is reduced especially with respect to NO.sub.2 and SO.sub.2. For this purpose, the oxide constituents of the coating are made of a metal conducting oxide of one element or an oxide mixture of several elements of the platinum metal group. Oxides of ruthenium and iridium have proven especially useful. The invention is also directed to an electrochemical measuring cell for measuring ammonia or hydrazine and includes at least a measuring electrode and a counter electrode in an electrolyte. The measuring cell provides a signal increase having a shorter response time and an improved signal stability.

Abstract: An electrochemical measuring cell has a three-electrode system including electrode, counter electrode and reference electrode in an electrolyte. The measuring cell has an additive promoting the electrochemical reaction and is selective and highly sensitive for the detection of hydrogen halides and also provides a stable measuring signal. A measuring cell of this kind has an additive of tetrachloroauric acid in the electrolyte for detecting hydrochloric acid with all electrodes being made of gold. The counter electrode is protected by a cation exchange membrane to provide a further improvement.

Abstract: The invention is directed to an electrochemical measuring cell for measuring ammonia or hydrazine and includes at least a measuring electrode and a counter electrode in an electrolyte. The measuring cell provides a signal increase having a shorter response time and an improved signal stability. For this purpose, the electrolyte is an aqueous solution of a hygroscopic salt of an alkali metal or earth alkali metal such as calcium nitrate or lithium nitrate or a mixture of both salts.

Abstract: The invention is directed to an electrochemical measuring cell for determining ammonia or hydrazine in a gaseous or liquid measuring sample. The measuring cell has at least one measuring electrode and at least one counter electrode which are disposed in an electrolyte chamber filled with a soluble electrolyte containing a cobalt salt dissolved therein. The electrolyte chamber is closed off in the direction facing toward the measuring sample by a permeable membrane. The measuring cell provides a selective ammonia measurement having the following advantages: a short response time, a linear response and a low tendency to drift. The electrodes of the measuring cell are so configured that the oxidation of the ammonia as a measurement reaction has no influence on the sensitivity of the measuring cell. For this purpose, at least the measuring electrode is provided with a coating containing cobalt oxide which is in direct contact with the electrolyte.

Abstract: The invention is directed to an electrochemical measuring cell for determining ammonia or hydrazine in a gaseous or liquid measuring sample. The measuring cell has at least one measuring electrode and at least one counter electrode which are disposed in an electrolyte chamber filled with a soluble electrolyte. The electrolyte chamber is closed off in the direction facing toward the measuring sample by a permeable membrane. The measuring cell provides a selective ammonia measurement having the following advantages: a short response time, a linear response and a low tendency to drift. The electrodes of the measuring cell are so configured that the oxidation of the ammonia as a measurement reaction has no influence on the sensitivity of the measuring cell. For this purpose, at least the measuring electrode is provided with a coating containing cobalt oxide which is in direct contact with the electrolyte.

Abstract: The invention is directed to an electrochemical measuring cell for detecting hydrogen cyanide or sulfur dioxide by means of at least one measuring electrode and a counter electrode disposed in an electrolyte. The electrolyte is accommodated in a measuring chamber closed off with respect to the ambient by a membrane permeable to the substance to be detected. This measuring cell is improved in that the long-term stability of the measuring signal is increased and a corrosion of the electrodes is prevented. For this purpose, the electrolyte in the electrolyte chamber contains an additive of copper salts for catalyzing the oxidation of the substance to be detected.