POPULAR CONFIGURATION GCs
Educational TCD
SuggestedClassExperiment:“Waiting toExhale”
CO
2
isanaturalby-productofhuman respiration. Our lungsgetoxygenwhenwe inhaleand release
CO
2
whenweexhale. Whenweholdourbreath, theconcentrationofCO
2
increases. In thisexperimentalgas
chromatographyanalysisofhumanbreath, thestudentswillsupplythesamples. Theywillexhaleintoandtrap
theirbreath in thesyringe, then itwillbe injected into theEducationalTCDsystemandanalyzed forCO
2
concentration. Haveacontest for thehighestCO
2
concentration: thestudentwith themostCO
2
inhisorher
breathwillwin. Whomeverpassesout isdisqualified!
1. Followsteps1-4of the
GeneralOperatingProcedure
.
2. InPeakSimple,setan isothermalColumnOven temperaturerampprogramasfollows:
InitialTemp.
Hold
Ramp
FinalTemp.
80.00
4.00
0.00
80.00
3. Locate the3mL(3cc)syringesuppliedwithyourGC, remove itsneedle,andgivebothparts toastudent.
Instruct thestudent toexhale into the tipof thesyringewhilepullingbackon theplunger. Studentsneednot
touchthesyringewiththeirmouthsforittowork. Fillthesyringecompletely, thenreplacetheneedle. Depress
theplungeruntil thesyringecontains0.5mLofbreath.
NOTE
: Forsanitationconcerns, itmaybeprudent tohaveonenew,sterilesyringeforeachparticipating
student. Sterile3mLsyringescompletewithneedlesmaybeacquiredforabout$0.18eachfrom:
VWR (800-932-5000):
BD-309587 Syringe-Needle,3mLSub-Q26
G
5/8Luer-lok
TM
4. Click theAutoZerobutton inPeakSimple, thenpress theRUNbuttononyourGCor thespacebaron
yourPCkeyboard tobegin the run.
5. Injectsample into theOn-Column injector.
6. Saveandprint theresultingPeakSimplechromatogramwiththestudent’snameforthesampleidentification.
Typical resultsareabout12-14areacountsper1%ofCO
2
.
7. Repeat steps2-5 foreachstudent. Comparechromatograms to find thewinner.
ExampleTCDBreathAnalysis
Column: 3’ SilicaGel
Carrier:Heliumat10mL/min
Sample:0.5cchumanbreath,
direct injection
TCDcurrent:LOW
TCD temperature:100
o
C
Results:
Component
Retention
Area
O
2
N
2
0.700
1379.4740
CO
2
2.700
61.9540
Total
1441.4280
TemperatureProgram:
Initial
Hold Ramp Final
80
o
C 24.00 0.00 80
o
C
