5
7890 Series GC Site Preparation Checklist
Issued: 09-Dec-2015, Revision: 1.8
Copyright
2013
Agilent Technologies
Page 5 of 15
Venting the uECD, TCD or Split-Splitless Inlet Vent gas flows to a Fume Hood or venting
manifold
If using a micro Electron Capture Detector, or if using hydrogen carrier gas that will be uncombusted,
you must either safely vent the exhaust gas, or operate the GC inside a fume hood.
For example, if using hydrogen carrier gas with a thermal conductivity detector (TCD) the GC would
vent uncombusted hydrogen from the detector and from the inlet split and septum purge vents.
The uECD exhaust vents through a stainless steel tube, connected to a length of large I.D. tubing that
exits the back panel. This should be routed to a fume hood or appropriate venting system. Agilent
Technologies recommends a vent line internal diameter of 6 mm (1/4-inch) or greater. With a line of this
diameter, the length is not critical. Make sure that the venting system does not put a direct negative
pressure on the vent tube from the GC.
Below is a picture that shows the back view of a 7890 GC with the micro Electron Capture Detector vent
tube exiting the back of the instrument.
Vent Line
from the
GC
Back
Panel
