User`s guide

Troubleshooting
369
pen clips are installed on your tubes, the tube
must be inserted into the carousel with the pen
clip facing in, toward the center of the carousel.
Cause: The sample is blocking the flow of carrier gas
through the sample tube.
Action: When analyzing solid or resinous materials,
ensure that the carrier gas flows can still pass
through the sample tube and that the sample is
not completely blocking the flow path.
Cause: The sample tube is not packed properly.
Action: Ensure the tube is not packed too tightly. You
must ensure there is the correct amount and type
of adsorbent for your application. Lastly, the
tube must be packed so that the sample is
retained only where the tube oven contacts the
tube. See Packing Sample Tubes on page 284
for details.
Action: If you are working with solid or resinous
materials, ensure that the sample is placed in the
center of the sample tube, and not within 1.5 cm
of either end of the tube. The tube oven only has
contact with the central portion (~6 cm) of the
tube.
Cause: There is incomplete secondary (trap) desorption.
Action: As with the problem of carryover from the
sample tube, adjust the method parameters to
achieve more efficient desorption.
Action: Select a weaker trap adsorbent.
Action: If you have repacked the trap yourself, it is
possible that it has not been packed correctly.
Refer to Repacking the Cold Trap on page 279
for details. It is highly recommended that you
order prepacked cold traps.
Cause: The PTFE filter disks are dirty.
Action: Change the PTFE filter disks contained within
the carrier gas flow path.
Action: Make certain that adsorbent material or sample