DETECTORS
Helium Ionization Detector - HID
Overview
TheHeliumIonizationDetectorisauniversaldetector,respondingtoallmoleculesexceptneon. Itrequires
onlyheliumcarrierandmake-upgas,and issensitive to the lowppmrange. TheHID isparticularlyusefulfor
volatile inorganics towhich theFIDandotherselectivedetectorswillnot respond, likeNOx,CO,CO
2
,O
2
,
N
2
,H
2
SandH
2
. It isa robust detector that, unlike theTCD, hasno filaments toburnout. TheSRIHID
consistsofadetectorbody,acollectorelectrode,anarcelectrodeassembly,anda thermostattedheaterblock
whichcanbeheated to375
o
C. InSRIGCs, theHID ismountedon theright-handsideof theColumnOven.
HIDdetector removed fromGCandheater block
Close-upof thesameHIDdetector
HIDdetectorbetweenTCDandFIDdetectors
onanSRIGC
HID
Collector
electrode
Arc
cross
Pointed
electrode
Flat
electrode
Detectorbody
Supportbrace
Makeup
gas inlet
Sample-laden
carriergas inlet
Arc
window
