Tuning in FI mode 9-21
Introducing the reference sample
The FI/FD outer source reference reservoir is essentially the same as the
EI/CI outer source except that the reservoir has a slightly larger internal
volume, and it is not heated.
The fused silica leak within the reference inlet re-entrant is 100 µm inner
diameter × 320 µm outer diameter. This allows the reference sample to bleed
into the source.
To introduce the reference sample:
1. Ensure that the reference reservoir valve is closed.
2. Use a septum-piercing syringe to inject approximately 3 µL of
chloropentafluorobenzene reference sample into the reference reservoir
septum.
Obtaining a beam and tuning in FI operation
To obtain a beam in FI operation:
1. In the MassLynx Tune window, click Ion Mode > FI.
Note: Use the same parameters initially in the TDC dialog box and the
Engineers tab as are used for the EI and CI operation.
2. In the FI Source tab set the following to 0: Flash Off Current, Emitter
Current, Extraction Voltage, and Heater Current.
See also: Table titled “FI Tune tab parameters:” on page B-29.
3. Clear Enable Flash Off.
4. Click to switch the instrument into Operate.
Caution: Do not close the Tune window in FI mode with the
instrument in operate. If you do, the emitter is damaged the next time
you open the Tune window. To avoid damaging the emitter if you do
close the Tune window while the instrument is in operate, pull the
emitter back into the lock, to protect it when you open the Tune
window.
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