General Operating Procedures
This technique is limited tovolatileorganiccompounds thatpurgeefficiently fromwaterat ambient
temperatureandVOC’s that arepurgeable fromsoil at40
o
C. Samplepreparationdependson thesample
type,concentration,amount,etc. The thirdeditionofSW-846from theEPA isaccessibleon theInternet. Go
to
andclickon the
5000Series
link todownload
Methods5030and5035. Also,pleasesee the“
SamplePreparation
”page in theSRIPurge&Trapmanual
section(availableonlineatwww.srigc.com).
1. The purge gas flow is controlledwith anElectronicPressureController (EPC). Set the purge flow
(measurableat the trapventat therearof thepurgeand trapsystem);40mL/min isa typicalpurgeflow. The
pressurerequiredfor40mL/min throughasingleTenax trap isprintedon therightpanelof theGC.
NEVER
usehydrogenasapurgegas
. SRI recommendsheliumpurgegas.
2. TRAP1 is in the lower position in thePurge&Trap, andTRAP2 is in theupper position. The trap
temperaturesare factorysetat200
o
C fordesorption. Foradsorption temperatures, trap1 issetat30
o
Cand
trap2issetat35
o
C. TrapheatingwillbecontrolledbythetimedEventTableduringtherun. NOTE:theactual
temperaturestypicallyrun5
o
Coverthesetpoint. SeetheinstructionsinthePurge&Trapsectionofthemanual
foradjusting the trapadsorption temperaturesettings.
3. Loador createanEventTable that isappropriate to the sample tobeanalyzed, or that isdesigned for
compliancewithaparticularEPAMethod (suchas
Epap&t1c.evt
forasingle trapor
Epap&t2c.evt
fordual
traps included inversion2.66orhigherof thePeakSimplesoftware).
4. LoadorcreateanappropriateTemperatureProgramfor thecolumnoven.
Epap&t.tem
isa typicalPurge
&Trap temperatureprogramfileprovidedwith thePeakSimplesoftwareforyourconvenience. Asabasic
ruleforgoodseparationusing thepurgeand trap injection technique, thecolumnovenshouldbekeptat40
o
C
for10-12minutes:6minuteswhile thesample ispurging,plus4-6moreminuteswhile the trapsheatand the
gassamplingvalve(in theINJECTposition) transfers thesample to thecolumn.
EPAStylePurge&Trap Injection
POPULAR CONFIGURATION GCs
BTEX & Environmental
Epap&t1c.evt
is
designed forone trap,
while
Epap&t2c.evt
is for two traps.
