The gas samples are analyzed using a gas chromatographic system PERKIN ELMER PE 8700 (GC/TCD/FID) with Flame Ionization (FID) and Thermal Conductivity (TCD) detectors on a Hayes Sep D column. The concentration of the gas components is calculated based on the peak areas calibrated against external standards of the pure substances. Hydrocarbon gases are measured from the FID signal, and non-hydrocarbons from the TCD one.