1986 Volume 2 Issue 6 Pages 571-575
An automatic system has been developed for the hourly analyses of trace hydrocarbons in the atmosphere. The system is based on cryogenic concentration followed by capillary gas chromatographic separation. In order to attain the quantitative transfer of the analytes to the capillary column and good chromatographic resolution, the analytes in the atmosphere were first collected in a small Tenax GC trap; then they were thermally desorbed into the cooled capillary column (-50°C). C3-C13 hydrocarbons could be analyzed quantitatively using this system. The detection limit for toluene was 50pg (70ppt in 175ml of sample air), and the precision was ±4% at the ppb level. The method has been successfully used to determine the diurnal variation of hydrocarbons in the atmosphere in the Tsukuba area.