GC DETECTORS
Reduction Gas Detector - RGD
General Operating Procedure
1. WhenyourRGDGCarrives, thephotodiodeamplifier leads
willhavebeendisconnectedfor transport. Locate the insulated
electricalleadwithtwoprotrudingwires:1black,1yellow. These
wiresplug into thebackendof theRGDassembly,where the
photodiode is located. Theblack is thegroundwire; plug it
ontotheupperprong. Plugtheyellowwireontothelowerprong.
2. TurnON themainGCpower (theswitch is locatedon the
left-handsideof theGC).
4. TurnON thedetector lampby flipping the switchon the
GC’sfrontcontrolpanel. Detectorheat isfactorysetat170
o
C,
whichishotenoughtokeepthemercuryvaporfromcondensing.
The reactor is factorysetat290
o
C(ahigher temperaturegives
greatersensitivity).
5. Themercuricoxideneeds time toequilibratewhen it isfirst installed,orwhen thereactor tube ischanged;
24hoursworkswell. Leave thereactoranddetector temperatureson theabovesettingscontinuouslywith the
carriergasflowingforday todayoperation.
6. Thefirstanalyticalrunof thedayshouldbediscarded,because thepurgedreactorwillgenerateunusually
highareacountswhichwill not be reproducibleonce thedetector equilibrates. The reactor canalsobe
poisonedbyveryhighsampleconcentrations. Purge timewithcleancarriergas isusually thebestcure.
3. Connectheliumornitrogencarriergas to thefittingson the
left-handsideof theGC. Thepressurefor therequiredflow is
printedon theright-handsideof theGC. Therequiredflowfor
theRGD is5mLs/minute. Thisflowgives thebestresponse.
photodiodeamplifier leads
yellow
black
