Theory of Operation
DETECTORS
Flame Photometric Detector - FPD
TheFPDusesoneof twoavailablebandpass filtersoveraphotomultiplier tube (PMT) toselectively
detectcompoundscontainingsulfurorphosphorusastheycombustinthehydrogenflame. Whencompounds
areburnedintheFPD flame, theyemitphotonsofdistinctwavelengths. Onlythosephotonsthatarewithinthe
frequency rangeof the filterspecificationscanpass through the filter to thePMT. ThePMTconverts the
photons it“sees” through thebandpassfilter toananalogsignal,which isacquiredby thePeakSimpledata
system.
Exhaust tube
Ignitor
Column
effluent
SecondaryH
2
inlet
intoPMThousing
10-pinsocket
Photomultipliersignal
cable toamplifier
SplitTeflon
TM
ferrule
Rubbero-ring
Photomultiplier
tube (PMT)
Jet
PrimaryH
2
inlet to jet
Air
inlet
Bandpass filterover
PMTwindow (394nm
forsulfur,526nm for
phosphorus)
Purgeair inlet
Purgeairoutlet
Ignitorblade
Ferrule
H
2
Stainlesssteel
retainingnut
Photons
SimplifiedFPDSchematic
