Agilent Technologies 6890 Series, Service Manual, Page: 467 / 867

520 Gases
Gas requirements
2 of 14
Jun 2001
Site Preparation
Agilent 6890 Gas Chromatograph Service Manual
Gases for capillary columns
When used with capillary columns, GC detectors require a separate makeup
gas for optimum sensitivity. For each detector and carrier gas, there is a
preferred choice for makeup gas. Table 520-2 lists gas recommendations for
capillary columns.
Table 520-2 Gas Recommendations for Capillary Columns
Detector Carrier
gas
Preferred
makeup gas Second choice Detector anode
purge or reference
gas
Electron Capture Hydrogen Argon/Methane Nitrogen Anode purge must
be same as makeup
Helium Argon/Methane Nitrogen
Nitrogen Nitrogen Argon/Methane
Argon/
Methane Argon/Methane Nitrogen
Flame Ionization Hydrogen Nitrogen Helium Hydrogen and
air for detector
Helium Nitrogen Helium
Nitrogen Nitrogen Helium
Flame
Photometric Hydrogen Nitrogen Hydrogen and air for
detector
Helium Nitrogen
Nitrogen Nitrogen
Argon Nitrogen
Nitrogen-
Phosphorus Helium Nitrogen Helium** Hydrogen and
air for detector
Nitrogen Nitrogen Helium**
Thermal
Conductivity Hydrogen* Must be same
as carrier and
reference gas Must be same
as carrier and
reference gas Reference must be
same as carrier and
makeup
Helium
Nitrogen