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Purge and Trap - SRI Instruments
Method 5030 & 5030/5035 Compliant Purge & Trap
76-77
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Built into the GC for lower dead volume and better peak
shape
no transfer line!
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Two independently heated Adsorbent Traps
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EPA Methods Compliant
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PeakSimple Control
Method 5030 Compliant
Purge & Trap
Built into the Model 8610C GC, the SRI Purge & Trap concentrates the volatile organic compounds (VOCs) in a gas,
water, or soil sample onto two adsorbent traps, from which they are automatically desorbed onto the GC column. The
Method 5030/5035 Compliant Purge & Trap is equipped with interchangeable purge heads. The 5035 purge head is
a thermostatted (typically 40
o
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 tubes which are purged at ambient temperature. For higher level soil samples or soil/
methanol extractions, the test tube is more convenient and less expensive than VOA vials.
Operation of the Purge & Trap is completely automated by the
that is built into the GC.
Run parameters such as purge time, desorb heat, bake-out, vial temperature, and mechanical agitation are adjusted in
a
The SRI Purge & Trap is unique because it is equipped with two traps rather than one, and each trap can be
heated independently at the adsorption temperature (typically 35-70
o
C), the desorption temperature (200
o
C), and the
bake-out temperature (250
o
C). For most VOC applications, the first trap is Tenax-GR, and the second trap is
Carbon Molecular Sieve. By setting the adsorption temperature of the Carbon MoleSieve to 50-60
o
C and the Tenax-GR
to 35
o
C, water retention is dramatically reduced. By staggering desorption times, early eluting peaks from the hot
Carbon MoleSieve trap are refocused on the temporarily cold Tenax-GR trap, resulting in much sharper peaks than
otherwise possible (see the chromatograms on the following page).
By comparing the relative response, the three detectors make
peak identification and confirmation easy. The
responds to all
hydrocarbons, the
responds to some hydrocarbons and all
aromatics, and the
responds to halogens only.