Determination of CO£¬CO2 and Light Hydrocarbons in Air by Gas Chromatography

KeyWord:greenhouse gas  open tubular capillary columns  gas chromatography  air  ethylene  acetylene

Abstract:

      A method was developed for the simultaneous determination of carbon monoxide£¬carbon dioxide and three light hydrocarbons i.e.methane£¬ethylene and acetylene in air by gas chromatography.The GC system consisted of auto-injection£¬one ten-port valve together with a six port valve and one ten-port valve in series with a four-port valve.Sample injection£¬column isolation and column back-flushing were realized in this way mentioned.An HP-PLOT Q open tubular capillary column was employed for the separation of the five gases followed by thermal conductivity detection.After the separation was completed£¬carbon monoxide and carbon dioxide were converted into methane with the use of a nickel-based methanizer for the detection by flame ionization.Separation of all the target analytes was achieved in one single analysis within 9 min.Carbon monoxide£¬methane£¬carbon dioxide£¬ethylene and acetylene were found to be linear over the ranges of 3.3-4 990.0£¬3.3-5 010.0£¬6.6-4 990.0£¬4.2-5 080.0,3.9-5 030.0 ¦Ìmol/mol£¬respectively.The correlation coefficients were not less than 0.997 with the detection limits of 1.0-2.0 ¦Ìmol/mol.Reproducibility of two levels£¬namely std1 and std2 were found to be not more than 3.5%(n= 5).This method was simple£¬accurate and maneuverable.