Abstract: An optical sensor is proposed for determining gases in gas mixtures, especially for determining one gas component in the air, having a sensitive layer exposed to the gas and having a device for detecting a change in an optical property of the sensitive layer. The sensitive layer of the sensor contains a phosphorus or nitrogen-containing base having numerous and/or long-chain alkyl groups for the pH adjustment of the sensitive layer.

Abstract: An optical sensor is described for determining the concentration of a gas in gas mixtures, which can especially be used for determining the carbon monoxide content of the air. It includes a radiation source, a sensitive layer positioned on a translucent substrate, and a detector. The sensitive layer of the sensor contains a transition metal compound which forms a transition metal complex with the gas to be determined.

Abstract: An optical gas sensor for determining a gas in a gas mixture, especially for determining a gas component in the air, is described, having a radiation source and having a sensitive layer positioned on a substrate. The sensitive layer of the sensor is porous and contains particles, which are optically transparent to a radiation emitted by radiation source and which lengthen the optical path of the radiation.

Abstract: An optical sensor is proposed for determining gases in gas mixtures, especially for determining one gas component in the air, having a sensitive layer exposed to the gas and having a means for detecting a change in an optical property of the sensitive layer. The sensitive layer of the sensor contains a phosphorus or nitrogen-containing base having numerous and/or long-chain alkyl groups for the pH adjustment of the sensitive layer.

Abstract: An optical sensor is described for determining the concentration of a gas in gas mixtures, which can especially be used for determining the carbon monoxide content of the air. It includes a radiation source, a sensitive layer positioned on a translucent substrate, and a detector. The sensitive layer of the sensor contains a transition metal compound which forms a transition metal complex with the gas to be determined.

Abstract: A sensor for detecting combustible gases in a test gas. The core of this sensor is comprised of a sensitive layer based on a semiconducting metal oxide that is deposited on a ceramic substrate and for which the electrical resistance provides information on the concentration of combustible gases in a test gas. The sensitive layer (3) is comprised of a compound (12) of sintered-together grains (15) of the semiconducting metal oxide, the surface of which is coated with gold and/or a gold alloy. The semiconducting metal oxide in this case is stannic oxide (SnO.sub.2), indium oxide (In.sub.2 O.sub.3), titanium oxide (TiO.sub.2) or another n-semiconducting metal oxide or metal mix oxide. The gold alloy, for example, is composed of 66 mol % gold and 33 mol % palladium (Pd).

Abstract: A sensor is proposed for detecting nitrogen oxides (NO, NO.sub.2, N.sub.2 O.sub.4) in a test gas, having a semiconducting metal oxide layer (3) which is deposited on a ceramic substrate (10) and whose electrical resistance provides information about the concentration of nitrogen oxides (NO, NO.sub.2, N.sub.2 O.sub.4) in the test gas. The main components of the sensor are a converter layer (4) which is deposited on the metal oxide layer (3) and is made of a material which causes the oxidation of combustible components of the test gas and converts the nitrogen monoxide (NO) contained in the test gas into nitrogen dioxide (NO.sub.2) or dinitrogen tetroxide (N.sub.2 O.sub.4), which then reaches the metal oxide layer (3), as well as a heating device (5) which heats the metal oxide layer (3) and the converter layer (4). The converter layer is suitably constituted of titanium oxide (TiO.sub.2) and/or zirconium oxide (ZrO.sub.2) and/or silicon oxide (SiO.sub.2) and/or aluminum oxide (Al.sub.2 O.sub.