86 Maintaining Your GC
5 Maintaining the Purged Packed Inlet
5
Tighten the inlet column nut 1/4 turn with a wrench.
6 After conditioning, remove the column from the inlet.
7 Simultaneously insert the column into the inlet and detector
fittings but do not force it. It may be necessary to start the long
end of the column in the inlet at an angle to clear the oven floor.
8 Withdraw the column 1 to 2 mm from both the inlet and
detector. Finger-tighten both column nuts.
9 Tighten both column nuts 1/4 turn with a wrench.
10 Configure the new packed column (make sure either column
length or diameter is zero).
11 Establish a flow of carrier gas and purge as recommended by
the packing manufacturer. Generally:
• 20 to 30 mL/min for 2-mm id glass or 1/8-inch od metal
columns
• 50 to 60 mL/min for 4-mm id glass or 1/4-inch od metal
columns
12 Restore the analytical method.
• For NPD, immediately set the bead voltage to 0.0.
13 After the GC becomes ready, wait 10 minutes then ignite the
detector flame or adjust offset on the NPD bead.
WARNING
Do not use hydrogen as the carrier for conditioning! It could vent
into the oven and present an explosion hazard.
CAUTION
Overtightening the column nut or forcing it to bottom in either the
inlet or detector may shatter the column.
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