User`s guide

Sampling Techniques
335
Figure 102 Soil Probe
GC Certified Standards on PerkinElmer
Tubes
Certified reference materials on PerkinElmer stainless steel sample
tubes are available from the European Community Bureau of
Reference (BCR). These standard tubes are produced for verifying
thermal desorption calibration procedures.
Tenax filled tubes spiked with benzene, toluene and m-xylene have
been shown to have a shelf life of at least two years, when they are
capped with ¼” Swagelok brass caps and PTFE ferrules.
The tubes were tested by charging approximately 1000 tubes with
known amounts of each vapor. The charging process ensured that all
tubes received exactly the same amount of each component.
Selected tubes were analyzed by 10 different laboratories, using a
thermal desorption/gas chromatographic procedure. On the basis of
these results, the contents of the tubes could be certified with very
small uncertainties.
Stainless Steel
Sample Tube
with Adsorbent
Silicone Membrane
Diffusion Cap
Brass Cap