User guide

Inlets 8
Advanced User Guide 213
• 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 5X 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 step 12.
14 Set a new vent time and initial inlet temperature time based
on the new time the needle spends in the syringe.
15 Make a 25 uL injection of your standard. Again, you should
see 5 times the response. If not, see step 13.
16 If you need more response, repeat steps 10 – 15 to increase
to larger volume. Also try performing 5 x 5 uL injections,
then 5 x 50 uL injections.
Multiple injections with the MMI
The preferred technique for concentrating analytes in the inlet
liner is to use a single, large volume injection. Using a high
capacity syringe and one septum puncture reduces the
possibility of contamination and generally improves results
when compared against a multiple septum puncture technique.
However, if needed, you can perform multiple septum punctures
during the vent time. This technique requires an Agilent data
system and automatic liquid sampler.
Data system requirements
An Agilent data system is necessary for multiple injection
because the needed parameters are not available through the
GC keyboard.
GC ChemStation Software revision B.04.01 SP1 or later.
MSD ChemStation Software revision E.02.00 SP2 or later
EZChrom Software revision 3.3.2 or later