6 Operating in CI Mode
To Set Up the Software for CI Operation
150 5977B Series MSD Operating Manual
•Ion polarity: Always set up in PCI with methane first, then switch to your
desired ion polarity and reagent gas.
•Abundance target: Adjust higher or lower to get the desired signal
abundance. Higher signal abundance also gives higher noise abundance.
This is adjusted for data acquisition by setting the EMV in the method.
• Peakwidth target: Higher peakwidth values give better sensitivity, lower
values give better resolution.
• Maximum emission: current Optimum emission current maximum for NCI is
very compound-specific and must be selected empirically. Optimum
emission current for pesticides, for example, may be about 200 µA.
Maximum current limit is 200 µA for EI and 250 µA for CI.