Peak At M/Z 32 - Agilent Technologies 7250 Troubleshooting And Maintenance Manual

3 CI Troubleshooting
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.

Peak at m/z 32

A visible peak at m/z 32 in methane pretune often indicates air in the system.
New or dirty reagent gas supply tubing
Purge the reagent gas supply lines and flow module for at least 60 minutes. See
the Agilent 7250 Accurate-Mass Quadrupole Time-of-Flight GC/MS System
Operating Manual for more information.
Air leak
Check for leaks and correct any that you find. See
all leaks have been corrected, clean the ion source.
Contaminated reagent gas supply. Suspect this if you have recently
replaced your gas tank, and you have ruled out air leaks.
Replace the reagent gas supply.
The capillary column is broken or disconnected.
Inspect the capillary column. Make sure it is not broken and it is installed
correctly.
Saturated methane/isobutane gas purifier
Replace the gas purifier.
7250 Accurate-Mass Q-TOF Troubleshooting and Maintenance Manual
"Air Leaks" on page 52. After
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