Method of detecting reative gases in a gas mixture

Abstract

Reactive gases like, for example reducing gases, specifically carbon monoxide, are detected in a gas mixture, particularly in air, with extremely high sensitivity and with high precision using a gas detector in which the attenuation of the intensity of an infrared radiation beam by a catalyst layer is utilized. Such catalyst layer contains at least one transition metal selected from at least one of the groups I, VII, and VIII of the Periodic Table of the Chemical Elements. Preferably, chemical elements are used having an atomic weight in the range of about 100 to about 205. The detection of carbon monoxide is particularly sensitive using a catalyst layer which substantially contains a metal capable of forming a carboncarbonyl compound with carbon monoxide. The sensitivity and precisionof detecting carbon monoxide and other reducing gases can be significantly increased by periodically exchanging the gas mixture to be investigated in a measuring chamber and replacing it with a pure reference gas from a reference chamber. The sensitivity and precision of the gas detection can be further increased by periodically alternating the temperature of the catalyst layer during such period of gas exchange. The alternating signal this obtained at an output of the gas detector can be evaluated for determining the concentration of the reactive or reducing gases in the investigated gas mixture.