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Volatile &
Semivolatile compounds in Solid Matrices
- Mounts in the Valve Oven on the 8610C GC
- High Temperature & High Sensitivity
- Manually Actuated 10-port Valve
- No solvent extraction required
- Simple to Use
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The
SRI Thermal Desorber permits volatile and semi-volatile compounds in soil,
or other solid matrices, to be injected and analyzed with little or no
sample preparation, and with very high sensitivity. With the Thermal Desorber,
no solvent extraction is required. This is a major convenience for field
operations, and helps save on costs. Little operator skill is needed,
and 4-10 analyses can be run per hour, depending on specific requirements.
Because of the large
sample sizeup to one gram, an analyte present in the soil at 1ppm
desorbs 1000 nanograms onto the GC column. This results in detection limits
in the ppb range for most compounds. Sandy soil can typically be desorbed
with no sample preparation at all. Clay soil is first mixed with sodium
sulfate granules to break the clay into a fine powder coating the granules,
then the clay and sodium sulfate mix is desorbed.
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This
chromatogram is from a GC with a Thermal Desorber and an FID
detector. Synthetic diesel range samples like this are used to
verify complete desorption. Sample: 2000ng synthetic diesel range
organics desorbed from soil. |
Up to one
gram of soil is loaded into a re-usable glass tube, and secured
in place with plugs of glass wool. The tube is then inserted into
the hot (275oC) thermal desorber
fitting, which is mounted in the heated valve oven compartment
on the 8610C.
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Soil samples
can typically contain 20-50% water. FID or FID/DELCD
detectors are commonly used with the Thermal Desorber, because the SRI FID
automatically re-lights the flame after a large water peak. The Thermal
Desorber + FID/DELCD configuration is perfect for detecting PCBs, pesticides,
PAHs, JP-4, kerosene, and diesel in soil. Due to the extreme selectivity
of the DELCD detector, PCBs can be discriminated even in the presence of
massive hydrocarbon contamination. |
These two chromatograms
show the analysis of PCB 1254 standard in diesel oil with our PCB
GC system, which is equipped with a Thermal Desorber and an FID/DELCD
combination detector. The FID shows the
diesel hydrocarbons and the PCBs, but the PCB peaks are obscured by
the diesel peaks. In contrast, the DELCD shows
the PCBs only, revealing what was essentially hidden in the FID chromatogram. |
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This set of chromatograms
show the analysis of a real world standard: 0.3 grams of soil from
a contaminated site. This real world standard is certified by NIST
to contain 1.34ppm PCBs. The FID shows a large
hydrocarbon matrix which is pre-combusted in the FID flame prior to
reaching the DELCD, which shows a clean PCB
1254 chromatgram. Pre-combustion of the sample by the FID protects
the DELCD from hydrocarbon contamination. |
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8690-1088
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Thermal
Desorber on 8610C GC including 10 re-usable glass desorber tubes |
£3,176.00
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8690-1087
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10-pack
re-usable ground glass desorber tubes |
£96.00
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