GC Injectors
70
Purge&Trap
For theSRI TO-14AirMonitoringGC
• Built into theGC for lower dead volumeandbetter
peak shape—no transfer line!
• Two Independently heatedAdsorbent Traps
• EPAMethodsCompliant
• PeakSimpleControl
Traps
Test tube
TheMethod5030CompliantPurge&Trapuses
disposable test tubes at ambient temperature.
TheMethod5030/5035
Compliant Purge&Traphas
interchangeablepurgeheads,
and a syringe port for adding
internal standardorwater.The
5035purge head is heated and
mechanicallyagitatedunder
PeakSimpledata systemcontrol.
5035purge head
Built-in to the Model 8610C GC, the SRI Method 5030/5035
Compliant Purge & Trap concentrates the volatile organic
compounds (VOCs) in a gas, water, or soil sample onto two
adsorbent traps, fromwhich they are automatically desorbed
onto theGCcolumn. TheMethod5030/5035Compliant Purge
& Trap is equipped with interchangeable purge heads. The
5035 purge head is a thermostatted (typically 40°C) sleeve
which accepts standard 40mL VOA vials. The entire sleeve
is mechanically agitated while purging to comply with the
requirements of EPA Method 5035. The 5030 purge head
uses low-cost, disposable 16mm test tubeswhich are purged
at ambient temperature. For higher level soil samples or soil/
methanol extractions, the test tube is more convenient and
less expensive thanVOA vials.
Operationof thePurge&Trap iscompletely
automatedby thePeakSimpledatasystem
that is built into the GC. Run parameters
suchaspurge time, desorbpreheat, bake-
out, vial temperature, and mechanical
agitation are adjusted in a PeakSimple
Event table.
The SRI Purge & Trap is unique because it is equippedwith two traps rather than one, and each trap can
be heated independently at the adsorption temperature (typically 35-70°C), the desorption temperature
(200°C), and thebake- out temperature (250°C). Formost VOCapplications, the irst trap isTenax-GR, and
the second trap isCarbonMolecular Sieve. By setting theadsorption temperatureof theCarbonMoleSieve
to 50-60°C and the Tenax-GR to 35°C, water retention is dramatically reduced. By staggering desorption
times, earlyelutingpeaks from thehotCarbonMoleSieve trapare refocusedon the temporarilycoldTenax-
GR trap, resulting inmuch sharper peaks thanotherwisepossible (see thechromatogramson the following
page).
