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5
Micro GC Channels
Column conditioning
Column conditioning
Follow this procedure to make sure that any water inside the analytical column is removed before
the TCD is switched on.
Column conditioning is specifically recommended if the 990 Micro GC has been inactive for a long
period of time.
The detector filaments may be damaged by improper conditioning. To avoid damaging the
C AU T I O N
detector filaments, follow this procedure.
Column conditioning procedure
1 Switch off the TCD filaments in the method.
2 Set the column temperature of the module to the maximum temperature
(110 °C, 160 °C, or 180 °C depending on the column limit). Leave the filaments off.
3 Set injector temperature to 80 °C.
4 Download this method to the Micro GC.
5 Keep the downloaded method to condition the column, preferably overnight.
This will ensure that all the water has been removed from the column, and no damage will occur
to the TCD filaments.
Nitrogen and oxygen merging in Molsieve columns
On a properly activated Molsieve column, nitrogen and oxygen will be well separated. However,
over time these two peaks begin to merge. This is caused by water and carbon dioxide present in
the sample or carrier gas, adsorbing to the stationary phase.
To restore the column efficiency, condition the column, for approximately one hour as described
above. After reconditioning, you can test the column performance by injecting plain air. If you have
a proper separation between nitrogen and oxygen, the column separation power has been
restored. The longer the reconditioning period, the better the column performance.
Agilent 990 Micro GC User Manual
73
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