User`s guide

Routine Maintenance
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Once the packed tubes have been thoroughly conditioned in this
way, subsequent conditioning runs (for example, after storage)
would only require one 10-15 minute desorption at the maximum
temperature of the packing.
Storage and Lifetime of Packed Tubes
Keep tubes capped and stored in a clean environment at all times. If
packed sample tubes have not been used recently, recondition them
before use. When the sample has been collected, analyze the tube as
soon as possible. If the tubes cannot be analyzed immediately, they
should be capped with Swagelok® brass ¼” caps (P/N 0990-8851)
and one-piece PTFE ferrule (P/N 0496-4467). These have been
evaluated by the European Community Bureau of Reference (BCR)
during their evaluation of certified standards on PerkinElmer tubes,
and have been shown to have a shelf life of at least two years.
NOTE: Never use tools to tighten the brass caps. Overtightening
the fitting will result in damage to the ferrules and possibly
damage to the tubes.
Avoid storing tubes that contain a sample in areas where high levels
of organic vapors may be present, such as refrigerators, car trunks
and airplane cargo holds. Tubes located in such areas must be capped
with the Swagelok caps.
Tubes transported by aircraft should be stored in pressurized areas of
aircraft, in a container, that is preferably hermetically sealed against
pressure changes.
Studies
1
carried out on Porapak N, (one of the least stable porous
polymers used as an adsorbent for thermal desorption) demonstrated
that the tubes could be used for approximately 100 sampling/
desorption cycles before the adsorbent started to deteriorate,
requiring the tube to be repacked. This represents a lifetime of about
2 years, assuming that tubes are sampled and desorbed on a
CAUTION
When conditioning tubes that are packed with more than one
adsorbent, do not exceed the maximum temperature of the
least thermally stable material present.
1. BASF performed these studies.