Common Ci-Specific Problems - HP 5973 MSD Hardware Manual

Troubleshooting
This chapter outlines the troubleshooting of HP 5973 MSDs equipped with
PCI/NCI. Most of the troubleshooting information in the HP 5973 MSD
Hardware Manual (G1099-90001) also applies to MSDs equipped with the
CI accessory.

Common CI-specific problems

Because of the added complexity of the parts required for CI, there are many
potential problems added. By far the greatest number and most serious
problems with CI are associated with leaks or contamination in the reagent
gas introduction system. NCI is especially sensitive to the presence of air,
and air leaks that cause no problems in PCI can destroy NCI sensitivity.
As with EI, if the MSD tunes well, and no air leak is present, sample
sensitivity problems should be addressed by GC injection port maintenance
first.
• Wrong reagent gas
• Reagent gas not hooked up or hooked up to wrong reagent gas inlet port
• Wrong ions entered in tune file
• Wrong tune file selected
• Not enough bake-out time has elapsed since vent (background is too
high)
• Wrong column positioning (extending > 1mm past tip of interface.)
• Interface tip seal not installed
• EI source installed in CI mode
• EI filament or other EI source parts in CI ion source
• Air leaks in reagent gas flow path
• CI filament has stretched and sagged:
High EMV
Linear (no inflection point) electron energy (EleEnergy) ramp.
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