Rapid Determination of 14 Components in Natural Gas by GC

GC method was applied to the rapid determination of 14 components in natural gas. Definite amount of the gas sample was taken and aliquoted automatically into 4 portions which were separated chromatographically by passing through 4 separated micro GC-columns and detected by 4 individual thermal conductivity detectors which are connected with each of the GC-micro columns. Fourteen components including methane, ethane, propane, nitrogen, oxygen, helium, hydrogen, carbon dioxide, isomers of butane and pentane and etc., in natural gas were separated and determined within 5 min by the method proposed. Linear relationships were found between values of peak areas and concentrations of the 14 components in definite ranges, with detection limits (3S/N) in the range of 11-19 μmol·mol-1 and RSD′s (n=8) less than 1%. The GC instrument was calibrated with the CRM GBW(E) 061322 and the method was applied to the analysis of natural gas of Si-chuan region.