A device suitable for the continuous detection of carbon monoxide evolved during thermal decomposition processes is described. The detector can be connected directly to thermoanalytieal equipment of controlled gas atmosphere. Carbon monoxide collected by the carrier gas is passed through the device containing hopcalite catalyst. In the presence of oxygen carbon monoxide is converted to carbon dioxide in the cell and the temperature change caused by the heat of reaction is measured. According to experience, the change of temperature is linearly proportional to the amount of carbon monoxide released.The signal curve of the detector can be compared to the simultaneously recorded thermoanalytieal curves and used to determine the step in which carbon monoxide was released.The detector is not completely selective to carbon monoxide, but in most eases the interferring gases can be removed from the carrier gas by various packings placed between the detector and the thermoanalytical equipment. The use of evolved gas analysis (EGA) techniques in thermal analysis