Topic History of: installing your column
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When installing your column into an FID jet,
never pass the column through the flame. This
will burn the inner (phase) and outer
(polyimide) coatings and will cause higher
background signals.
Purge column with oxygen-free carrier gas for
at least 30 minutes before heating GC oven.
When storing a capillary column, seal the
column ends with a used septum. Remember to
cut at least 3cm from each column end before
re-installation.
If you're having problems with solvent
focusing, or early eluting peaks seem broad
or lop-sided in splitless injection, then try
using a column with a thicker film.
Set the FID temperature 20°C above the
maximum method temperature, 250°C is usually
the recommended temperature.
When peak shape deteriorates, replace the
liner immediately and cut 30cm from the front
end of the column.
When changing your column, liner or septum,
SGE recommends lowering the injector
temperature to <100°C to prevent stripping
the liner deactivation. This is especially
important for the analysis of trace levels of
active compounds.
Always re-tighten Graphite / Vespel® ferrules
by ¼ to ½ turn after the first 2-3 oven
cycles.
To prevent increasing retention times in your
chromatography, replace the septum daily.
Condition column at:
a. 20°C above the method temperature or
b. the recommended maximum column temperature
(whichever temperature is lower).
If the injection port temperature is not
specified in the method, 250°C is usually the
recommended temperature.
Always use SilTite™ or Graphite/Vespel®
ferrules when connecting a column to a GC/MS
interface.
For maximum FID sensitivity, set the air flow
10 times higher than the hydrogen flow.
To extend the lifetime of your packed column,
ensure the oven temperature is 50°C, or less,
before turning off the carrier gas.
Do not use plastic tubing in GC systems.
Plastic tubing, when used for general
plumbing, can absorb up to 20% moisture
allowing external laboratory gases to
transpire through the tubing. SGE recommends
stainless steel tubing to be used throughout
the GC system. |
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