9-26 FI/FD Operation
Running samples
Running MS samples in GC FI mode
You must set a use solvent delay at the beginning of an acquisition when
running in GC FI mode.
See also: Setting a solvent delay on page 4-9.
The solvent delay is set so that the solvent front has completely eluted before
the end of the solvent delay time. During the solvent delay period, the
extraction voltage is turned off. This ensures that the extraction voltage is not
at a high pressure in the ion source.
Using direct insertion probe in FI mode
Samples which are involatile can be run using the direct insertion probe. The
rotational adjustment knob on the DI probe insertion lock allows the end of
the DI probe to be set at a fixed distance away from the emitter.
The distance should be set to approximately 10 mm away from the emitter.
The closer the DI probe is to the emitter, the more the field around the
extraction rods will be distorted, resulting in a loss of sensitivity.
Note: Tune the instrument with the DI probe inserted into the ion source in
the correct position.
See also: Controlling the DI probe temperature on page 7-10.
Caution: Failure to protect the system from the solvent front can
damage the emitter.
Caution:
• The inner source lock is incompatible with the direct insertion lock.
When using the direct insertion probe in FI mode, you must fit the
FI/FD inner source direct insertion probe flange.
See also: Installing the FI/FD inner source direct insertion probe
only flange on page 9-9.
• You cannot use the DCI probe in FI mode.
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