46
GCDetectors
FID - Flame IonizationDetector
• HydrocarbonSelective
• Robust, Linear, Stable
• DetectsDown to 1ppm
• UniqueCeramic Ignitor can runHOT
continuously tokeepflame lit
Ignitor
Thischromatogramshows250ppmC
1
-C
6
hydrocarbons
(methane throughhexane) standardas detectedby the
FID.CO
2
, alsoat 250ppm, is converted tomethaneby
theMethanizeraccessoryinthe jetof theFIDdetector.
The Flame Ionization Detector is the most commonly
used GC detector, responding linearly from its minimum
detectable quantity of about 100 picograms to almost
100%.
The FID responds to any molecule with a carbon-
hydrogen bond, but not at all, or poorly, to
compounds such as H
2
S, CCl
4
or NH
3
. The FID
response is very stable from day to day, and is not
susceptible to contamination from dirty samples or
columnbleed.
TheSRI FIDemploysauniqueceramic ignitorwhich
can run hot continuously, immediately reigniting
the lame even when presented with large water
injectionsorpressuresurges fromcolumnbacklush.
TheFID is thermostatted inanaluminumblockup to600°C, and is equippedwithanelectrometer ampliier
withHIGH, HI-FILTERED (for extra noise immunity), andMEDIUM gain settings. Hydrogen and air low are
controlled using Electronic Pressure Controllers (EPC) for high precision. The optional built-in, “whisper-
quiet” air compressor canbe used to supply the air for the FID, eliminating thebulky air cylinder.
If CO and CO
2
are target analytes, order our Methanizer accessory (page 76) for the FID detector. The
Methanizer allows the FID to detect low levels of CO and CO
2
by converting them to methane without
changing their retention times. Thermostatted to 380°C, theMethanizer is a special catalyst jet which can
be removed for normal FIDoperation.
8690-0010
FIDdetector
8690-0082
Methanizer Jet for low level CO&CO
2
8690-0070
Optional 115VAC 60Hzbuilt-in “whisper quiet” air compressor
8690-2270
Optional 230VAC 50Hzbuilt-in “whisper quiet” air compressor
