Shimadzu GC-2010 Plus - Thermal Conductivity Detector (TCD); Principle of TCD Operation

13 Detector
13.3
13.
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GC-2010 Plus
13.3Thermal conductivity detector (TCD)
13.3.1 Principle of TCD operation
The thermal conductivity detector (TCD) can detect all compounds except the carrier gas
itself.
When a filament heated by the application of current is provided in a gas atmosphere with a
high thermal conductivity such as helium, the filament temperature rises as sample compo-
nents with a lower thermal conductivity pass the filament. The filament temperature changes
affect its resistance; the resistance is measured and produces a peak.
A reference filament also exists, where only carrier gas flows, to eliminate background resis-
tance fluctions.
Fig. 13.3.1