Operating in Chemical Ionization (CI) Mode 4
Operating the CI MS
Operation Manual 75
Operating the CI MS
Operating your GC/MS in the CI mode is slightly more
complicated than operating in the EI mode. After tuning, gas
flow, temperatures (Table 5), and electron energy may need to
be optimized for your specific analyte.
Start the system in CI mode
When starting up the system you may begin in either PCI or NCI
mode. Depending upon the application, use the following
reagent gas flowrates during system startup:
• PCI mode set reagent gas flow to 20 (1 mL/min)
• NCI mode set reagent gas flow to 40 (2 mL/min)
Table 5 Temperatures for CI operation
Ion source Analyzer GC/MS interface
PCI 300 °C 150 °C 280 °C
NCI 150 °C 150 °C 280 °C