80 Maintaining Your GC
5 Maintaining the Purged Packed Inlet
To Bakeout Contaminants from the Purged Packed Inlet
1 Set the column flow to the normal operating value, or set the 
capillary column gas velocity to 30 cm/s.
2 Purge the column with carrier flow for at least 10 minutes 
before heating the oven.
3 If the column is attached to the detector, set the detector 
25  °C above normal operating temperature.
If the column is not attached to the detector, cap the detector 
fitting.
4 Set the inlet temperature to 300  °C or 25  °C above the 
normal operating temperature.
5 Set the column oven 25  °C above the GC method final oven 
temperature to bake contaminants out of the inlet. Do not 
exceed the column manufacturer’s maximum temperature 
limit.
6 Bakeout for 30  minutes or until the detector baseline is free 
of contamination peaks.