Installation manual

98 5975 Series MSD Operation Manual
4 Operating in Chemical Ionization (CI) Mode
General Guidelines
• Always use the highest purity methane (and other reagent gases, if
applicable.) Methane must be at least 99.9995% pure.
• Always verify the MSD is performing well in EI mode before switching to CI.
See “To verify system performance” .
• Make sure the CI ion source and GC/MSD interface tip seal are installed.
• Make sure the reagent gas plumbing has no air leaks. This is determined in
PCI mode, checking for m/z 32 after the methane pretune.