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Gas considerations
Gas considerations
Gases for packed columns
The choice of carrier gas depends on the detector selected and what
performance is required from it. These relationships are shown below. In
general, makeup gases are not needed with packed columns.
Gas Recommendations for Packed Columns
Detector
Thermal
conductivity
(TCD)
Flame
ionization
(FID)
Nitrogen/
Phosphorus
(NPD)
Electron
capture
(ECD)
Note A: Slightly greater sensitivity than helium, but may remove passivation from fila-
ments causing high drift rates until passivation is completely reduced. Incompatible
with some compounds.
Note B: For analysis of hydrogen or helium; greatly reduces sensitivity for other com-
pounds (some peaks may invert).
10
Carrier Gas
Helium
Hydrogen
Nitrogen
Argon
Nitrogen
Helium
Helium
Nitrogen
Nitrogen
Argon/Methane
Comments
General use.
Maximum sensitivity (see Note A).
Hydrogen detection (see Note B).
Maximum hydrogen sensitivity (see Note B).
Maximum sensitivity.
Acceptable alternate.
Optimum performance.
Acceptable alternate.
Maximum sensitivity.
Maximum dynamic range.
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