B-48 The MassLynx Tune window
See also: Instrument Setup Wizard Nominal Mass: on page 3-11
To set up Veff manually:
1. Introduce a known standard compound into the reference reservoir (for
example, heptacosa).
2. Reduce the amount of sample using the reference reservoir value so that
the intensity of the signal is less than 1000 counts per second in
continuum mode to avoid saturation effects.
See also: Effects of saturation on peak shape on page B-51.
3. In the Tuning Setup dialog box, Data Format list, click Centroid.
4. Observe a known peak on the Tune window.
Tip: For example, observe the peak at m/z 218.9856 when using
heptacosa.
5. In the TDC Settings dialog box, set the Veff to 5300.
Note: With Veff set to 5300, the peak should be within m/z ±10 of the
correct mass.
To alter the mass of the peak of interest:
1. Increase Veff to move the peak to higher mass.
2. Decrease the Veff to move the peak to lower mass.
3. In the TDC Settings window adjust the Veff so that the peak is at the
correct mass (to within m/z 0.1).
4. Click OK.
Note: Veff is automatically determined by the Instrument Setup wizard.
See also: Instrument Setup Wizard Nominal Mass: on page 3-11.
Setting up resolution for dead time correction manually
The resolution value on the TDC Settings window is used for digital dead time
correction (DDTC). It is set up automatically during the Instrument Setup
wizard.
See also: Instrument Setup Wizard DDTC Setup: on page 3-13.
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