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Thermal Desorber - SRI Instruments
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 (275
o
C)
thermal desorber fitting, which is mounted in the heated valve oven
compartment on the
Soil samples can typically contain 20-50% water.
or
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
, which is
equipped with a Thermal Desorber and
an
.
The
shows the diesel hydrocarbons
and the PCBs, but the PCB peaks are
obscured by the diesel peaks. In
contrast, the
shows the PCBs
only, revealing what was essentially
hidden in the FID chromatogram.
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
e prior to reaching the
DELCD
,
which shows a clean PCB 1254
chromatgram. Pre-combu
he
sample by the FID protects the DELCD
from hydrocarbon contamination.