Flame Ignition - Thermo Scientific TRACE GC Ultra Maintenance And Troubleshooting Manual

FID Troubleshooting
The FID sensitivity will be reduced as hydrogen flow rate is above or below the
optimal value. The flow rate of the air is less critical than the hydrogen one. An
excessive amount of air will destabilize the flame, causing noise and eventual
flameout.
NOTE Generally the air flow rate must be set to about 10 times the hydrogen flow rate to keep the
flame lit.
A low flow rate of air would reduce the detector sensitivity.
The guidelines in Table 11-4 show typical FID operating conditions.
For high sensitivity applications, it is essential that you exclude all traces of
organic contamination from the chromatographic system and/or from the gas lines
of the detector. Such contamination would cause ghost peaks in the chromatogram
or, more commonly, an unstable baseline.
WARNING! It is the customer's responsibility to ensure compliance with all local safety
regulations concerning gas supplies.
Hydrogen is a potentially dangerous gas. Mixed with air it may give rise to an
explosive mixture. The use of hydrogen requires the operator's extreme caution due
to the risks involved. For further details concerning hydrogen, please refer to
Hydrogen

Flame Ignition

You can ignite the flame as soon as the detector temperature has reached 150°C.
Maintenance and Troubleshooting Manual
Table 11-4. Typical FID Operating Conditions
Gas
Carrier
Hydrogen
Air
Make-up gas (Nitrogen)
on page xvii.
Capillary Columns
2 mL/min
35 mL/min
350 mL/min
30 mL/min
Chapter 11
Maintaining a FID
Packed Columns
40 mL/min
40 mL/min
500 mL/min
Not used
Using
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