3
Tuning
Tuning the Mass Spectrometer
Thermo Scientific
TSQ 8000 Evo User Guide
35
voltage is set to a low value to improve resolution, which is also tuned. The detector
gain is calibrated to generate 300,000 electrons for every ion that strikes the detector.
Additionally, this tune generates spectra that are the closest in appearance to the
factory tune.
i.
Fast Scan Tune
—This tune retunes the system with fixed Q1 voltages necessary for
fast scanning. By increasing the ion energies and shortening ion flight times through
the mass analyzer, this tune provides increased ion signal required to tune resolution
and perform mass calibration at a high scan rate. This tune may cause high mass ions
to exhibit more fronting than the other built-in tune types. This tune performs a leak
check and sets the detector gain to 300,000. It does not tune the detector gain. Run a
fast scan tune when scanning above 10,000 amu/s to improve the mass calibration for
high mass ions.
j.
CI- Tune
—Used to analyze samples with negative CI. The standard NCI tune
performs a mass calibration, then tunes the lenses and sets the resolution. This type of
tune assumes you are using methane as the CI reagent gas and tunes the system with
a 1.0 mL/min flow. This tune does not set the detector gain. The built-in CI- tune
will start with the most recent AutoTune_NCI tune file, so have an appropriate tune
file saved on the instrument's PC.
k.
CI+ Tune
—Used to analyze samples with positive CI. The standard PCI tune
performs a mass calibration, then tunes the lenses and sets the resolution. This type of
tune assumes you are using methane as the CI reagent gas and tunes the system with
a 1.5 mL/min flow. This tune does not set the detector gain. The built-in CI+ tune
will start with the most recent AutoTune_PCI tune file, so have an appropriate tune
file saved on the instrument's PC.
4. Select the
Display Report When Complete
check box so that you can view the tune
report after running the tune.
Note
If you are starting with a clean source, first run the EI Initial Tune as a reset
tune. After this tune is complete, follow it with your preferred tune.
Note
Chemical ionization tunes are very different from the electron ionization
tunes. Do not use a CI tune unless your instrument has a CI ion volume and CI
reagent gas installed.
Note
If the instrument was last used in EI mode and tuned with a high repeller
voltage before switching to a clean CI ion Source, a tune file with a low repeller
voltage should be loaded in manual tune and saved to the instrument before
tuning in CI mode.
Note
To add a tune type to the list, see
Содержание TSQ 8000
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