Chapter:. FlODETECTOR
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Operation of
FlO
detecto.r
without
hydrogen (
FLiomode )
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In the FLiDmode, the ignitor itself provides the heat
necessary to ionize the samplemolecules. Accord–
ingly, the ignitor needs to be positioned directly in
front of the jet. The slight angle of the ignitor allows
the ignitor tip to
be
located 1-2mm in front and
slightly above the jet. The ignitor is held in place by a
soft graphite ferru le and a swagelok nut. Be careful
when manipulating or twisting the ignitor because the
ignitor blade is very brittle ceramic. and will snap
if
stressed. Replacement ignitors are available using
part#
8670-0150.
The ignitor temperaturemust
be
raised so that
it
glows red hot. Set the FlO ignitor volts to at least
900-1000 using the front panel FlO Ignitor control.
A chromatogram of gasoline is shown below which
was run using the FLiDmode.Only the larger gaso–
line components (
>
1000 ppm ) were detected.
Sensitivity is exponential due to the temperature rise
that occurswhen the peak combusts on the ignitor
surface. Large peakswhich elute quicklymay cool
the ignitor resulting in split peaks.
Manl44.pub
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