62 Troubleshooting and Maintenance Manual
3 CI Troubleshooting
The CI ion source is dirty.
Clean the ion source. See the Agilent 7200 Accurate-Mass Q-TOF GC/MS
System Operation Manual.
The calibration valve was not purged after the vial was refilled.
Purge the calibration valve as described in “To Refill the CI Calibration Vial”
on page 93. Then clean the ion source.
The calibrant vial was overfilled. Excess PFDTD can quench the chemical
ionization reactions.
Check the level of the PFDTD in the calibration vial. It should be below the end
of the inside tube in the vial.
Poor quality methane (purity below 99.99%)
Replace the methane with high-purity methane. If necessary, clean and purge
the reagent gas lines and clean the ion source.
Excessive noise or low signal-to-noise ratio
The GC inlet needs maintenance.
Refer to the GC manual.
The CI ion source is dirty.
Clean the ion source. See the Agilent 7200 Accurate-Mass Q-TOF GC/MS
System Operation Manual. for more information.
Poor vacuum
Check the pressure on the high vacuum gauge controller.
Air leak
Run Methane Pretune (in PCI). Large peak at m/z 32 indicates air in the
system. Check for and correct any leaks. See “Air Leaks” on page 52.
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