3
CI Troubleshooting
Peak at m/z 32
A visible peak at m/z 32 in methane pretune often indicates air in the system.
Residual air from recent venting — check for water indicated by a large peak at
m/z 19.
Bake out the system under vacuum to eliminate water.
New or dirty reagent gas supply tubing
Purge the reagent gas supply lines and flow module for at least 60 minutes.
See the
Air leak
Check for leaks and correct any that you find. See
After 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.
76
Operation
Manual.
5975 Series MSD Troubleshooting and Maintenance Manual
"Air Leaks"
on page 60.