A simple and efficient method based on the technique of valve switching is developed for the analysis of H2, Ar, O2, CO, CH4, CO2 and C2. A total of 3 valves and 6 columns are used in this GC system. Sample is introduced into one sample loop for determination. H2 is detected by TCD-1. The other permanent gases and CH4 are directed into column-2 through Valve 2. Ar, O2, N2, CH4 and CO flow through column-3(MS-13X), are separated and detected by TCD-2. CO2 and the light hydrocarbons are directed on to a porous polymer column for separation and detected by TCD 2.