ISQ User Guide - Write Frame of Mind

4 Creating a Method
• The Filament On column is used to turn the filament on and off in the selected
segment. Turning off the filament increases the lifetime of the filament and keeps
the ion source clean longer. However, no data will be collected. Use this column
if you had analytes eluting before the solvent peak. You can create a segment to
turn off the filament during the solvent peak to preserve the filament.
• The Emission Current column is used to set the emission current used during
the acquisition. For optimal analytical performance and stability, use the
emission current at which the system was tuned. However, if you want to use a
different emission current, deselect the Use Tune File Emission Current
checkbox and enter a value in the Emission Current (μA) column. A high
emission current will lead to the production of more ions, but the interaction of
too many ions in the source can cause a degradation in the resolution and signal.
• The Use Last Tuned Detector Gain column is used to indicate that you want to
use the detector gain set in ISQ Autotune. If you do not need to use the gain set in
ISQ Autotune, then you can set the gain manually. Higher gains give larger
signals, but may shorten the lifetime of the detector when concentrated samples
are detected.
• The CI Gas Flow column is used to set the flow rate of your reagent gas.
• The Cal Gas column is used to turn on the calibration gas during a run. This
setting can be useful when confirming that the system is generating ions and
correctly storing the data to disk. Typically, the setting is off, but you can let a
low level of calibration gas into the source by selecting EI. If you have a dual-flow
calibration gas module, you can select CI for a high level of gas.
Thermo Scientific ISQ User Guide 39