Single filament TCD detector operation
TheSRI single filament TCD is
mounted on the right side of the
GC’s column oven. More than one
single filament TCD detectormay
bemounted in this location ( up to
6 ). In the photo, a single filament
TCD ismounted alongside a four
filament TCD detector.
The single filament TCD detector
is always energized. The 50milli-
amp filament current is low enough
that no filament damage can occur
evenwith room air in the detector.
The top chromatogram at right
shows 1ml 10ppm hydrogen in
room air using argon as carrier gas
using the single filament TCD.
The lower chromatogram shows
the same sample on the 4 filament
TCD detector on low ( 80milli-
amps ) filament current.
Compared to the four filament
TCD the single filament is about
the same raw sensitivity, but exhib-
itsmore baseline noise and drift. It
is however less expensive on ini-
tial purchase andmuch less ex-
pensive tomaintain since the sin-
gle filament can be replaced in
minutes for under $100.
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Four filament
Single filament
Hydrogen
