62 Advanced User Guide
4 Columns and Oven
Setting temperatures for the nickel catalyst tube
The nickel catalyst tube is usually mounted in the back inlet
position and controlled by the back inlet temperature setpoint.
For most analyses, set these temperatures:
• Nickel catalyst tube—375 °C
• FID—400 °C
Table 10 Gas flows for a TCD/FID series installation
Gas Flow rate, mL/min
Carrier (helium) 30
TCD switching flow 25
FID hydrogen 45 (see Caution)
FID air 500
CAUTION
Hydrogen flow is pressure-controlled, where an FID provides a
known resistance. The nickel catalyst tube increases flow
resistance, so that the calibration is no longer valid. You must
measure hydrogen flow with a bubble or similar meter.
The nickel catalyst can be damaged by exposure to air.
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