5
Operating in CI Mode
General Guidelines
• Always use the highest purity methane (and other reagent gases, if
• Always verify the MSD is performing well in EI mode before switching to CI.
• Ensure the CI source and GC/MSD interface tip seal are installed.
• Ensure the reagent gas plumbing has no air leaks. This is determined in PCI
• Ensure the reagent gas inlet line is equipped with gas purifiers (not
120
applicable). Methane must be at least 99.9995% pure.
(See
"To Verify EI System Performance"
mode, checking for m/z 32 after the methane pretune.
applicable for ammonia).
on page 108.)
5977B Series MSD Operating Manual