5. Turn theTCDcurrentON toLOW. Ignite theFID, ifpresent,byholdingup the ignitorswitch (lableled
“FLAMEIGNITE”)foracoupleofsecondsuntilyouhearasmallPOP. The ignitorswitch is locatedonyour
GC’sfrontcontrolpanelunder theheading“DETECTOR
PARAMETERS.”VerifythattheFIDflameislitbyholding
theshinysideofachromedwrenchdirectly infrontof the
FIDexhaustvent. The flame is litwhencondensation is
visibleon thewrenchsurface.
If present, switch on theHID current and set it to 100
using the trimpotandLOCALSETPOINTbutton. You
shouldbeable toseeapurplearcbetween the twoHID
electrodes.
Pleasesee theDETECTORSsection inyourSRImanualformore information.
6. Ethane is the firstpeak toelute from theSilicaGelcolumnafter theH
2
,O
2
,N
2
,CH
4
,andCO,whichare
separatedby theMolecularSievecolumn. TheethaneandCO
2
willgetstuck in theMolecularSievecolumn
if thegassamplingvalve isnot rotatedback into theLOADposition (by turningRelayGOFF)prior to the
ethaneelution. Therefore,youmustdeterminetheelutiontimeofethane,sothatyoucansetaneventprogram
thatwillrotate thevalveat theright timeduring therun. Type inaneventprogramasfollows:
Time Event
0.00 Zero
0.1 GON
0.3 GOFF
ThiseventprogramwillinjectthesampleloopcontentsintotheSilicaGelcolumn,thenimmediatelyreversethe
columnssothesamplewillnotentertheMolecularSievecolumn. Sinceethaneisthefirstpeakoffthecolumn,
it iseasy todetermine itselution time.
7. Set thecolumnoven temperatureprogramasfollows:
Initial Hold Ramp Final
40
o
C 6.00 10.00 200
o
C
8. Zero thedata system signal by clickingon theAuto
Zero iconon the left sideof thechromatogramwindow.
Injectasamplecontainingethaneintothegassamplingvalve
throughthesampleinletonthefrontofthevalveoven. Start
the runbypressing thecomputerkeyboardspacebar, or
bypressing theSTARTbuttonon the front ofyourGC.
Note theelution timeofethane.
General Operating Procedures continued
10. Revise the temperature program if necessary. The temperature
programusedfor the testchromatogramon theExpectedPerformance
pageworkswellwith theaboveeventprogram.
Injectionbysyringeof
gassample intovalve
AutoZero icon
Initial Hold Ramp Final
40
o
C 4.00 20.00 220
o
C
9. Revise theeventprogramso thatRelayG
turnsOFF justbefore theethanepeakbegins
torisefromthebaseline. Atypicaleventtable
for theMG#1GCsystem isshownat right.
Time Event
0.00 Zero
0.1 GON
6.0 GOFF
POPULAR CONFIGURATION GCs
Multiple Gas Analyzer #1
