DETECTORS
Dry Electrolytic Conductivity Detector - DELCD
General Operating Procedure continued
FID/DELCD - FIDOnly
1. Remove theDELCDheaterwires from thepush terminals. Remove the threeDELCDcollector and
thermocouple wires(yellow,whiteandred)from thescew terminals.
2. Disconnect theDELCDdetectorassembly from theFIDexhaustbyusingawrench to loosen the1/4”
Swagelokfittingsecuring the twodetectorparts together.
3. Useacapnut toseal theDELCDconnectionon theFID flameport.
4. SettheFIDamplifiergainswitchtoHIGHformosthydrocarbonapplications. Ifpeaksofinterestgooffthe
scale(greater than5000mV),set thegain toMEDIUM. Whenpeaksof interestare20secondswideormore
at thebaseandextranoise immunity isdesired,set thegainswitch toHIGH(filtered). Thissettingbroadens
thepeaksslightly.
5. Set theFIDhydrogen flow to25mL/min,and theFIDairsupply flow to250mL/min. Theapproximate
pressuresrequiredareprinted in thegasflowcharton theright-handsideof theGC.
6. Ignite theFIDbyholdingup the ignitorswitch foracoupleofsecondsuntilyouhearasmallPOP. The
ignitorswitchislocatedonthefrontpanelofyourSRIGCunderthe“DETECTORPARAMETERS”heading
(itislabelledvertically:“FLAMEIGNITE”).
7. VerifythattheFIDflameislitbyholdingtheshinysideofachromedwrenchdirectlyinfrontofthecollector
outlet. Ifcondensationbecomesvisibleon thewrenchsurface, theflame is lit.
1. Set theheliumcarriergasflow to10mL/minand theairmake-upflow to25mL/min. Clean,dry tankair
helps toobtain thebestachievableDELCDsensitivityandsignalstability.
2. Set theDELCD reactor temperaturesetpoint to260 (=1000
o
C)byadjusting the trimpoton the topedge
of theGC’sfrontcontrolpanel. TheDELCDwillheat toabout254andstabilize. Theceramic tube willglow
brightredfrom theheat.
3. Byadjusting theappropriate trimpot, set the thermostattedDELCDheaterblock temperature to25
o
C
higher than the“Final” temperatureyouhaveentered in the temperatureprogram.
4. TheDELCDamplifier isnormallyoperatedonLOWorMEDIUMgain.
DELCDOnly
