The Methanizer option enables the Flame Ionization Detector to detect low levels of CO and CO2. It is installed as the removable jet in a special FID detector assembly. The Methanizer is packed with a nickel catalyst powder. During analysis, the Methanizer is heated to 380oC with the FID detector body. When the column effluent mixes with the FID hydrogen supply and passes through the Methanizer, CO and CO2 are converted to methane. 
 
Since the conversion of CO and CO2 to methane occurs after the sample compounds have passed through the column, their retention times are unchanged. Hydrocarbons pass through the Methanizer unaffected. 
 
The special Methanizer FID detector assembly operates like the regular Buck FID detector, except that the FID temperature must be set to 380°C. Due to the chemical relationship between nickel and sulfur, the Methanizer can be poisoned by large quantities of sulfur gas.