Agilent Technologies 5975C TAD VL MSD Troubleshooting And Maintenance Manual page 69

No peaks
When troubleshooting "no peaks" it is important to specify what mode of
operation is being used and what expected peaks are not being seen. Always
start with methane PCI and verify presence of reagent ions.
No reagent gas peaks in PCI
If MSD has been working well and nothing seems to have been changed
• Wrong tune file loaded, or tune file corrupted
• Wrong ion polarity (there are no reagent ions visible in NCI)
• No reagent gas flow; look for background ions and check pressure
• Wrong reagent gas selected for the tune file (looking for wrong ions)
• Large air leak
• Dirty ion source
• Poor vacuum (pump problem). See
If MSD was recently switched from EI to CI
• Interface tip seal not installed
• No reagent gas flow
• Analyzer not sealed (big air leak)
• Wrong tune file loaded or tune file corrupted
• Ion source not assembled or connected correctly
• Wrong reagent gas selected for the tune file (looking for wrong ions)
No PFDTD peaks in PCI
• Incorrect reagent gas. There are no PCI PFDTD peaks created with
• Analyzer not sealed (big air leak)
• No calibrant in vial
• Defective calibration valve(s)
• Air leak in carrier or reagent gas path
5975 Series MSD Troubleshooting and Maintenance Manual
isobutane or ammonia. Switch to methane.
CI Troubleshooting
page 64.
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