Simultaneous Determination of 5 Inorganic Gases in Ethylene or Propylene by GC with Pulsed Discharge Helium Ionization Detector

GC with pulsed discharge helium ionization detector was applied to the simultaneous determination of 5 inorganic gases, i.e. H₂, O₂, CO₂, CO and N₂ in ethylene or propylene. The fully gasified sample was introduced into the chromatograph. With the help of the highly intensive operational program of the instrument and the switching function of the valve system, the 5 gases, i.e. H₂, O₂, CO₂, CO and N₂ were separated and determined successively during passing of the sample through 2 packed micro-chromatographic columns. Linear relationships between values of peak area and volume fraction of the 5 gases were found in the same range of 0.50 to 10.0 mL·m^-3, with detection limits (3S/N) of 0.02, 0.01, 0.02, 0.03, 0.01 mL·m^-3 respectively. A set of standard gas mixture of the 5 gases was analyzed by the proposed method for 8 repeated determinations, giving values of RSDs for retention time in the range of 0.040% to 0.15%, and RSDs for peak area in the range of 0.98% to 2.3%, and showing good repeatability of the method in simultaneous determination of the 5 gases. Another set of standard gas mixture of the 5 gases was analyzed in parallel for 6 times, giving results in consistency with the known values, and RSDs (n=6) of determination values all less than 1.0%.