Tuning in FD mode 9-29
5. Increase the Extraction Voltage to 12,000 V in increments of 2000 V,
while monitoring the leakage current.
6. Introduce acetone into the reference reservoir until the source pressure
reaches 1e-5 mbar.
Note: This is approximately 20 µL.
7. In the Engineer tab Solvent Trip pane, adjust the Source Solvent Trip to
allow the source pressure to rise.
8. Adjust the Beam Steering to maximize the acetone peak at 58 Da.
Rationale: The emitter position will have changed slightly when it is
taken out. Adjust the beam steering to compensate for any movement.
Any resulting voltage change should be less than 4 V.
Calibration and setup in FD
The calibration and set up for FD operation is the same as FI operation. If the
signal is weak it is better to acquire in continuum and calibrate from the
spectrum.
See also:
• Calibrating and accurate mass in FI mode on page 9-24.
• Manual calibration on page 5-19.
Alternatively, you can load a calibration solution such as polyethylene glycol
(PEG) on the emitter together with your sample. Calibrate the data using the
spectrum window.
Running an FD experiment manually
When the instrument has been tuned, using acetone, an acquisition can be
started over the mass range of interest.
To run an FD experiment manually:
1. In the Tune window, click .
Caution: Do not enable the Flash Off or raise the Emitter
Current above 0 at this stage.
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