INJECTORS
PTV -ProgrammedTemperatureVaporization Injector
The Programmed Temperature Vaporization injector is basically a Heated Split/Splitless injector
with the ability to rapidlyheat to300
o
C. This ballistic heating capability enables large volume liquid
sample injections. ThePTV injector canbeusedasa thermal desorber forvolatilesand semi-volatiles,
onlineoroffline. Multiple linerswithdifferent adsorbentpackingsmaybe interchanged in theSRIPTV
injector. Theadsorbentuseddependson thecompoundsof interest,aseachhas itsownselective retention
properties.
TheoryofOperation
Largevolumeinjectionsallowanalysisofsampleswithlowconcentrationoftargetanalytes. Liquidsamples
from1µL to200µLmaybe injectedusing theSRIPTV injector.
B.
The split vent is then
turned OFF, the PTV
injector is ramped to 200-
300
o
C, and thecarrier flow
transfers the analytes onto
thecolumn,whichisstillcool
at this point. The cool
column
temperature
promotescondensationand
focusingof theanalytesand
helpsprevent smearingand
excessive tailing. Each of
theseeventsisautomatically
controlled through the
PeakSimpledatasystem,so
operators can precisely
control their timing. The
operator sets the PTV
injector temperature by
adjustingwithascrewdriver
the appropriately labelled
setpoint on theGC’s front
panel.
A.
Tobegin,both theColumnOvenand thePTV injectorareheldat40-60
o
C. Prior to injection, thesplitvent
isopened. Thus, thelargevolumeliquidsampleisinjectedintothePTVinjectorat40-60
o
Cwiththesplitwide
open. Introducingthesample
ata low temperatureallows
thesolvent toventwhile the
injectorlinerpacking retains
higherboilingpoint analytes.
1) LargeVolumeLiquid Injector
A
B
