Dual Adsorber-Capillary Column System for Gas Chromatographic Analysis of Air Samples (Systeme Mixte Adsorbeurs-Colonne Capillaire pour la Chromatographie en Phase Gazeuse d'Echantillons d'Air)

摘要

An interface which allows thermal desorption and subsequent capillary gas chromatographic analysis of air samples is described. A small solid sorbent trap is positioned between the sampling tube and capillary column. A sample thermally released from the sampling tube is transferred by a carrier gas at high flow rate to the trap and retained. From there it is again thermally released and transferred to the capillary column by carrier gas at a low flow rate, as required by capillary GC. The transfer and injection steps are effected by means of externally placed solenoid valves. The performance of the system depends on the desorption temperature and time allowed for transfer of the sample between the two adsorbers and the column. These parameters are programmable and can be changed to suit the requirements of a particular analysis. The system allows the analysis of sub-parts-per-billion concentration levels in a comparatively simple and reproducible manner. Operation of the system does not require cryogenic cooling of either the trap or the GC oven. Chromatograms of a variety of air samples are presented and discussed. (Author)