Agilent Technologies 7000 Triple Quadrupole GC/MS, Maintenance Manual

Page: 67 / 214

CI Troubleshooting
3
Troubleshooting and Maintenance Manual 67
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 7000 Series Triple Quad GC/MS
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 54.
Saturated methane/isobutane gas purifier
Replace the gas purifier.
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.
Reagent gas flows too high (in EI/PCI MSs)
Verify that the reagent gas setup is correct.