Agilent Technologies 7000 Triple Quadrupole GC/MS, Maintenance Manual

Page: 63 / 214

CI Troubleshooting
3
Troubleshooting and Maintenance Manual 63
If MS 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
isobutane or ammonia. Switch to methane.
• Analyzer not sealed (big air leak)
• No calibrant in vial
• Defective calibration valve(s)
• Air leak in carrier or reagent gas path
No reagent gas peaks in NCI
• Reagent gases do not ionize in NCI; look for background ions instead
•
Verify tune parameters
• If no background ions are visible, go back to methane PCI
No PFDTD calibrant peaks in NCI
• Look for background ions: 17 (OH
–
), 35 (Cl
–
), and 235 (ReO3
–
)
• Verify tune parameters
• Go back to methane PCI
No sample peaks in NCI
• Look for background ions: 17 (OH
–
), 35 (Cl
–
), and 235 (ReO3
–
)
• Go back to methane PCI
• Poor quality reagent gas (purity less than 99.99%)
Large peak at m/z 238 in NCI OFN spectrum
•
Look for background ions: 17 (OH
–
), 35 (Cl
–
), and 235 (ReO3
–
)
• Find and fix your small air leak