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Finnigan GasBench
Hardware Components
II ___________________________________________________________ Open Splits
Principle of Active Open Split
•
left side:
no dilution
•
right side:
dilution active
The transfer of the sample stream into the IRMS is achieved via the open split.
The capillary that leaves the second water trap enters the open split interface
as well as the retractable sampling capillary of the IRMS. A third capillary
(protection capillary) delivers a constant stream of dry helium, which purges
the exit volume of the open split at any time.
"OUT" position
•
The gas from the protection capillary mixes with the sample flow.
•
The IRMS capillary "sniffs" the diluted sample stream.
"IN" position
•
The IRMS capillary is moved to the bottom of the open split.
•
The IRMS capillary "sniffs" the sample stream eluted by the capillary
that comes from the second water trap.
Note. Notice a difference between GC applications and GasBench
applications:
In case of GC applications, the mass spectrometer capillary is completely
decoupled from GC.
In case of GasBench applications however, only partial decoupling occurs.
Thermo ____________________ Finnigan GasBench II Operating Manual __________________ 2-37
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