DETECTORS
Photo Ionization Detector - PID
Overview
ThePhotoIonizationDetector(PID)respondstoallmoleculeswhoseionization
potential isbelow10.6eV, includingaromaticsandmoleculeswithcarbondouble
bonds. ThePID isnondestructive, so thesamplecanbe routed through thePID
andon tootherdetectors. It isoftenused inserieswith theFIDand /orDELCD.
PIDdetectionlimitsforaromaticsareintheppbrange;purgeandtrapconcentration
of thesamplecan lowerdetection limits to theppt range. Becauseof itsselective
sensitivity,useof thePID ismandated inseveralEPAmethods. ThePIDdetectorconsistsofa10.6electron
volt(eV)UV lampmountedona thermostatted, low-volume(100µL),flow-throughcell. The temperature is
adjustablefromambient to250
o
C. Threedetectorgain levels(LOW,MEDIUMandHIGH)areprovidedfor
awide rangeofsampleconcentrations. ThePID lamp isheld inplacebyaspring-loadedplate, so that the
lampmaybequickly removed forcleaningand replacedwithoutanyspecial tools. ThePIDcan runonair
carrierforgaslessoperation,orforstreammonitoringapplicationswheretheentirestreamofsampleisdirected
through thedetector(nocolumn isused).
110PID
stand-alonedetector
BNCconnector toamplifier
Amplifiergainswitch
Highvoltageband inblackplastic
hoodover lampanode ring
Spring-loaded
retainingplate
100µLdetectorcell
(thearea in the
centerof the
Teflon
TM
seal ring)
Heaterblock
Collectorelectrode
Collectorelectrode
supportunion
Benzene
PID inseries
withaDELCD
andanFIDon
anSRI8610C
chassis
