one such adsorbent is graphitized carbon black such as carbopack b manufactured by supelco the restricted outlet 72 serves the dual purpose of firmly retaining the adsorbent 76 and significantly reducing the dead volume between the adsorbent 76 and the column 80 preferably a glass quartz wool plug 78 is located above the adsorbent 76 both to facilitate mixing of the sample vapor and the carrier gas and to serve as a surface on which nonvolatile residues from the sample vapor are deposited thereby permitting easier cleaning of the liner 26 as shown in fig6 the column 80 may be inserted directly into the bottom of the liner 26 referring again to fig2 through 3 a threaded collar 40 secures a septum assembly 42 to the housing 36 at the top of the metal sleeve 22 a septum cap 44 secures a septum 45 to the top of the septum assembly 42 through which septum a microsyringe 82 may inject the sample the septum assembly 42 has a main carrier gas inlet 46 the pressure of which can be regulated which is located above and separated from the chamber 24 by an internal seal 48 such as an o ring additionally septum assembly 42 has a septum purge outlet 50 the septum assembly mechanically defines the path of the septum purge flow to prevent cross contamination with the sample flow path preferably a u201c split u201d vent 52 for splitting the gas mixture is located below the internal seal 48 and is in fluid communication with the chamber 24 preferably a column isolating accessory 60 such as the prevent u2122 system manufactured by perkinelmer instruments llc is interposed between the bottom of the injector 20 and the.