General Operating Procedures
Thefollowingaregeneralizedoperatingguidelinesfor theSRIPurge&Trapsystem.
1. Thepurgegas flow iscontrolledwithanElectronicPressure
Controller(EPC). Set thepurgeflow(measurableat the trapvent
at the rearof thepurgeand trapsystem). 40mL/min isa typical
purgeflow. Thepressurerequiredfor40mL/min throughasingle
Tenax trap isprintedon therightpanelof theGC. Ifyou install the
optionalCarbosieve traporanotheradsorbent trap in theTRAP2
position,youwillneed toraise thepressure tomaintain theflow.
NEVERusehydrogenasapurgegas
. SRIrecommendshelium
purgegas.
2. TRAP1 is in the lowerposition in thePurge&Trap,andTRAP
2 is in theupperposition. The trap temperaturesarefactorysetat
200
o
C for desorption andmay be adjusted using the trimpot
setpoints on the top edge of theGC’s front control panel. For
adsorption temperatures, trap1 isset at30
o
Cand trap2 isset at
35
o
C. Trapheatingwillbecontrolledby the timedEventTable
during the run.
Note:
theactual trap temperatures typically run
5
o
Cover thesetpoint. See the informationand instructionson the
following2pages foradjusting the trapadsorption temperature
settings.
3. Set thevalveoven temperature to100
o
Corhigher toavoidwatercondensation. Ifyou’reusingMethod
5035, set thepurgeheadheaterbody temperature to40
o
C. It is factoryset to40
o
Cbut isuseradjustable.
4. Loador createanevent table that is appropriate to the sample tobeanalyzed, or that isdesigned for
compliancewithaparticularEPAMethod. Thevalveoven inyourPurge&Trapsystem is labeledwitha
typicalPurge&Trapevent tableforasingleTenax trap. Theevent tableshownabove isanexampleforboth
methods; theonlydifference is thatMethod5030doesnotuseRelayD(thesamplevialshaker).
5. Loadorcreateanappropriate temperatureprogramfor thecolumnoven.
Epap&t.tem
isa typicalPurge&
Trap temperatureprogramfileprovidedwith thePeakSimplesoftware. Asabasicruleforgoodseparation,
thecolumnovenshouldbekeptat40
o
Cfor10-12minutes:thefirst8minutesoftherunplus2-4moreminutes
after thevalveactuates to theINJECTposition.
6. Activateandenergize thedetectorsasnecessary. For instance, ifyouhadanEnvironmentalGCsystem,
youwouldturnonthePIDlampcurrent, lighttheFIDflame,andsettheDELCDreactortemperature. Choose
thedetectorgainsettingsaccording to theanalysis. Consult themanualsectionsforyourparticulardetector(s)
operatingprocedures.
7. When thesystem isat temperatureanddisplayingastablesignal, insert thesample test tubeorVOAvial
into thepurgeheadandbegin theanalysis.
INJECTORS
Purge & Trap
