User`s guide

Operation
148
Operating Modes
NOTE: The screen above shows operating modes for a
TurboMatrix 650 ATD.
The ATD/TD can operate in any one of five modes. A basic
overview of each mode is provided here. A detailed description of
each, including flow diagrams are shown in Chapter 8
Troubleshooting.
Two Stage Desorption—This is the mode used to perform most of
the analyses.
Primary Desorb takes place after the sample tube has been leak
tested and purged of air. It is heated for a set period while a stream of
inert gas sweeps the volatiles, contained in the tube, onto the cold
trap where they are re-concentrated. The cold trap contains an
adsorbent material to trap the volatile sample components. At the
end of this period, Secondary Desorb takes place. The cold trap is
heated rapidly to release the volatiles onto the GC column.