EPAMethod 25 ( true carbon counting )
GC configuration part# 8610-1025
EPAMethod 25 specifies aGC
which is equippedwith an oxidizer
catalyst, a reduction catalyst
(methanizer ) andFID detector
which together convert all hydro-
carbons ( andCO, CO2 ) tometh-
ane for the purpose of measuring
the true carbon content of the
samplewithout the errors due to
differingFID response to different
molecules ( all molecules are con-
verted tomethaneprior to the
FID ).
TheMethod 25GC configuration
includes ahigh capacity reduction
catalyst (methanizer ) which is
mounted near theFID detector.
The high capacitymethanizer is
designed for long life and for easy
catalyst replacement in theevent
of poisoning. Aconvenient on/off
switch allows the catalyst tempera-
ture to be reduced for efficiency
testing. Themethanizer is nor-
mally operated at 380C.
An oxidizer catalyst and oxygen/air
supplyEPC ( electronic pressure
controller ) ismounted on theGC.
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External sample
loop for quick
loop size
changes
