Inlets 3
Advanced Operation Manual 119
• Set a Vent flow of 100 mL/min as a starting point.
• Keep the inlet isothermal for now.
• Enter a Vent pressure of 0 psi (0 kPa) and Vent end
time of 0.1 minutes.
d Make an injection using the empty vial. Use a
stopwatch or your GC's timer feature to time how long
the needle is in the inlet.
8 Enter revised Solvent vent mode parameters.
• Set the method's Vent end time to be about 0.05 min
longer than the time the needle spends in the inlet.
• Set the inlet temperature Initial time to be about 0.05
min longer than the Vent pressure time.
• Program the inlet to ramp quickly to the injection
temperature. Make sure the ramp starts after the Vent
end time.
• Set the Purge Flow to 30 mL/min. Set the purge time to
be the vent pressure Vent end time + 1 minute.
9 Make a 5 uL injection of your standard. You should see 5
times the response.
If the response of all analytes is too low:
• The dispense speed is too fast. Liquid was injected into
the inlet and pushed out the vent.
• The vent time is too long. The inlet started to heat
while the vent was open.
If the response of early eluters is too low:
• The inlet temperature is too high.
• The Vent flow is too high.
If the response of late eluters is too low:
• The purge time is too short.
• The final inlet temperature is too low.
10 If you need more injection volume and the 5 uL worked
to give 5 times the response, change the syringe to a
larger one, for example, 50 uL.
11 Set up the data system to perform a 25 uL injection.
12 Configure the syringe. Make sure the plunger speeds on
the injector are still set properly.
13 Recheck the injector timings. See the step above.
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