7
Diagnostics and Troubleshooting
Troubleshooting
Thermo Scientific
TSQ Quantum XLS and TSQ Quantum GC User Guide
141
Issue:
The
chromatogram has a
low total ion current
signal.
Possible causes/solutions
• The GC temperature ramp does not continue to a high enough temperature to elute high
boiling point compounds. Multiple injections cause these compounds to accumulate in a
column, reducing sensitivity. Extend upper temperature or the time at upper temperature
in the GC oven ramp.
• The instrument is out of tune, or the tune file is incorrect. Select correct tune file for the
method or run automatic tune as described in
.
• The ion volume is contaminated. Clean the ion volume.
• The ion volume is incorrectly positioned. Position the ion volume properly.
• The magnets above and below the ion source are installed incorrectly. Position both
magnets so the south pole is on top. Electrons will not focus into the ion volume if one
magnet is upside down.
• Dust has collected in the electron multiplier or on the conversion dynode. Contact
Thermo Fisher Scientific Technical Support.
• The emission current is set too low. Check the setting listed for the emission current.
Choose
Tune > Manual
and select the
Controls
tab.
• The ground connection between the electrometer PCB and anode feedthrough is faulty.
Contact Thermo Fisher Scientific Technical Support.
• There is a problem with the filament or lens control. See
for more information.
• The EI/CI Source PCB is faulty, allowing emission current to leak to ground. Contact
Thermo Fisher Scientific Technical Support.
• Reagent gas is leaking into the analyzer, suppressing EI signal. Check for presence of CI
reagent ions in spectrum. Replace CI Gas Flow Module if necessary.
Issue:
Poor
compound sensitivity.
Possible causes/solutions
• The syringe, injection port liner, and column depth in injector are incorrectly matched.
See
TRACE GC Ultra Operators Manual
for the correct combination.
• Sample delivery is insufficient due to a plugged syringe needle. Clean or replace the
syringe.
• The injection port liner is contaminated. Clean or replace the injection port liner.
• Graphite or septa particles contaminate the injection port. Clean the injection port.
• The injector or septum is leaking. Replace septum and perform leak check on the GC.
• The capillary column is at the end of its life span. Replace the capillary column.