Abstract: A monitor for monitoring the concentration of oxygen in a fuel or in an ullage over a fuel comprises (i) a sensing element comprising a luminescent substance comprising a luminophore and a support in which the luminophore is covalently bound to the support, (ii) a light source arranged to irradiate the sensing element with light, and (iii) a photosensor arranged to detect light emitted from the luminescent substance. The luminescent substance may be, for example, a platinum porphyrin covalently bound to silica.

Abstract: A monitor for monitoring gas concentration in an aerospace application is described, one such application being measuring the concentration of oxygen in or next to aviation fuel. The monitor comprises: a substance, the spectroscopic properties of which change when the substance is exposed to the gas; a light source, arranged to irradiate the substance with light; and a photosensor, arranged to detect light from the substance. The substance may be mounted on a solid substrate.

Abstract: A method of detection of a volatile compound in a gaseous atmosphere comprises irradiating a semiconducting metal oxide material with ultraviolet light, exposing the irradiated material to the gaseous atmosphere and determining the presence of any volatile compound in the atmosphere by monitoring a change in electrical conductivity of the material. The method can detect non-polar organic compounds as well as polar compounds. Zinc oxide particles in the nanometre size range are preferred. The method may be used for medical diagnosis or for environment monitoring purposes.

Abstract: A monitor for monitoring the concentration of oxygen in a fuel or in an ullage over a fuel comprises (i) a sensing element comprising a luminescent substance comprising a luminophore and a support in which the luminophore is covalently bound to the support, (ii) a light source arranged to irradiate the sensing element with light, and (iii) a photosensor arranged to detect light emitted from the luminescent substance. The luminescent substance may be, for example, a platinum porphyrin covalently bound to silica.

Abstract: A monitor for monitoring gas concentration in an aerospace application is described, one such application being measuring the concentration of oxygen in or next to aviation fuel. The monitor comprises: a substance, the spectroscopic properties of which change when the substance is exposed to the gas; a light source, arranged to irradiate the substance with light; and a photosensor, arranged to detect light from the substance. The substance may be mounted on a solid substrate.

Abstract: A method of determining the cause of disease is described, which method uses the detection of “signature” or “fingerprint” volatile compounds in an emission, especially flatus, from a patient.