Tuning-Related Symptoms; Reagent Gas Ion Ratio Is Difficult To Adjust Or Unstable - Agilent Technologies 7250 Troubleshooting And Maintenance Manual

3 CI Troubleshooting

Tuning-Related Symptoms

This section describes symptoms related to tuning. Most symptoms involve
difficulties with tuning or with the results of tuning. The following symptoms are
covered in this section:
•
•
Reagent gas ion ratio is difficult to adjust or
unstable
The interface tip seal is incorrectly placed, damaged, or missing.
Inspect the interface tip seal. If necessary, remove and reinstall it to ensure a
good seal with the CI ion source. Replace it if it is damaged. Install it if it is
missing.
Residual air in the MS or in the reagent gas supply lines
Run an air and water check. See the software online help for additional
information.
Air leak
Run an air and water check. See the software online help for additional
information.
The reagent gas supply is at the wrong pressure.
Check the regulator on the reagent gas supply. It should be adjusted to 20 psi
(138 kPa).
A leak in the reagent gas delivery path. This is especially likely if you have
set the methane flow much higher than normal and the ratio is still too low.
Check the reagent gas path. Tighten fittings.
The CI ion source is dirty.
Clean the ion source. See the Agilent 7250 Accurate-Mass Quadrupole
Time-of-Flight GC/MS System Operating Manual for more information.
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CI ion ratio is difficult to adjust or unstable
Cannot complete autotune
7250 Accurate-Mass Q-TOF Troubleshooting and Maintenance Manual