instrumentation
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Instrumentation
Most of the components we supply to the instrumentation industry are from
our valve and fitting lines. The rest, from our R&D 100 Award-winning pulsed
discharge detectors to our application-dedicated trace gas analyzers, are
primarily for gas detection and purification.
Pulsed Discharge Detectors
Non-Radioactive, Multiple Mode
Electron Capture / Helium Photoionization
R&D 100 award
winner
VICI PDDs (pulsed discharge detectors)
utilize a stable, low powered, pulsed
DC discharge in helium as an
ionization source. Eluants from the
column, flowing counter to the flow of
helium from the discharge zone, are
ionized by photons from the helium
discharge. The bias electrode(s) focus
the resulting electrons toward the
collector electrode, where they cause
changes in the standing current which
are quantified as the detector output.
Performance is equal to or better
than detectors with conventional
radioactive sources.
In the electron capture mode, the PDD
is a selective detector for monitoring
high electron affinity compounds
such as freons, chlorinated pesticides,
and other halogen compounds. For
this type of compound, the minimum
detectable quantity (MDQ) is at the
femtogram (10
-15
) or picogram (10
-12
)
level.
In the helium photoionization mode,
the PDD is a universal, non-destructive,
high sensitivity detector. The response
to both inorganic and organic com-
pounds is linear over a wide range.
Response to fixed gases is positive
(increase in standing current), with an
MDQ in the low ppb range.
The PDD in helium photoionization
mode is an ideal replacement for
FIDs in petrochemical or refinery
environments, where the hydrogen
and flame can be problematic. In
addition, when the discharge gas is
doped with argon, krypton, or xenon
(depending on the desired cutoff
point), the PDD functions as a specific
photoionization detector for selective
determination of aliphatics, aromatics,
amines, and other species.
more information
Pulsed discharge
detectors
Model D-2 . . page 221
Model D-3 . . . . .222
Model D-4 . . . . .223
Model D-5 . . . . .222
Plug-and-play detectors
for Agilent 6890 . . 222
for Agilent 7890 . . 222
for other GCs . . . .223
CHROMalytic TECHnology Pty Ltd AUSTRALIAN Distributors e-mail:
Tel: 03 9762 2034
