Thermo Scientific ISQ, User Manual

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4
Creating a Method
Creating a Method for the ISQ Mass Spectrometer
42 ISQ User Guide Thermo Scientific
e. The Filament On column turns 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 have
analytes eluting before the solvent peak. You can create a segment to turn off the
filament during the solvent peak to preserve the filament.
f. Use the Emission Current column 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.
g. The Use Last Tuned Detector Gain column indicates that you want to use the
detector gain set in ISQ Autotune or set and scanned in manual tune. 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.
h. Use the CI Gas Flow column to set the flow rate of your reagent gas. Remember to
set the CI gas flow in the Groups column as well as at the top of the method editor.
The single value at the top of the method is sent when initializing the MS with the
method.
i. Use the CI Gas Type column to set the type of gas attached to one or both CI gas
ports (A or B). Be sure that the gas you have assigned to a port is actually attached to
that port, as each CI gas has a specific calibration of flow vs. gas viscosity.
9. The Cal Gas column turns 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 may let a low level of calibration gas into the source
by selecting EI. If you have a dual-flow calibration gas module, you may select CI for a
high level of gas.
10. Choose ISQ | View Tune Report to view the latest tune report the method will use.
Choose Report Options to open the Report Options dialog box (see Figure 31 ) and add
identifying information to the tune report.