Configuring The Ion Source Parameters - Thermo Scientific TSQ 8000 Evo User Manual

5
Optimizing Your Method
Modifying an Automatic Tune
98 TSQ 8000 Evo User Guide
Figure 97. Configuring the Ion Source Parameters
a. Ionization Mode & Ion Polarity—Use this pull-down menu to select a mode:
• Select EI + to run a tune in Electron Ionization (EI) mode.
• Select CI+ to run a tune in Chemical Ionization (CI) mode and positive ions.
• Select CI- to run a tune in CI mode and negative ions.
b. CI Gas Type (only enabled if you select CI+ or CI-)—Use this pull-down menu to
select a gas type, but make sure your selection is the reagent gas attached to your
system and that the correct gas port is selected. Methane is commonly used for CI+.
Other gases will change the efficiency and energy of the ionization process.
Note When changing CI gas types or gas port, there is a two minute delay while
the reagent gas is purging. During this time, the Busy light will be lit and you
have to wait until the light goes off before using the software.
c. Emission Current—Defines the emission current that you use to run subsequent
tunes, but not the emission current that is used for data acquisition.
• Tune File—Select this option to use the value in the tune file that you selected
on the General tab.
• Default—Select this option to use the default emission current, which is 50 μA.
• Custom—Select this option if you want to use a value other than 50 μA when
increasing or decreasing the sensitivity of the instrument. For the emission
current, the default is 50 μA. Tune with the same value you are planning to use
for your analysis. The use of emission currents above 100 μA may lead to the
generation of too many ions in the source and a degradation in resolution.
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