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Sum parameter – Total Organic Carbon
TOC determination in soils, sludges and
sediments using the solid sample module
SCA-130-108
To characterize soils, sludges or sediments, ■ TOC determination
the total organic carbon parameter (TOC) is To investigate the TOC in soils or other solids
regularly used. In addition to naturally such as sediments or sludges, a solid sample
occurring organic components in these solids, module is used which enables TOC
undesirable organic contaminations caused determination using the difference method
by man and industry are also often present. and the NPOC method.
These organic compounds frequently are
risks. Solids to be disposed or utilized must
be tested on their TOC content. The organic
contaminations can contaminate ground
water, for instance when leached out. In
addition, hazardous gases such as methane
can be formed through biological activities in
the soil and compromise the safety of
landfills. The formation of such gases or the
biological decomposition of organic materials
in soils, inevitably lead to the formation of Here, a subsample of the dried solids is
cavities that reduce the stability of the weighed into a ceramic boat and combusted
materials and renders them unsuitable for at 900 °C in a stream of oxygen. To ensure
specific application areas, such as road complete conversion to CO 2, the generated
construction. gases are passed over a mixed catalyst
(cobalt/platinum) for catalytic post-
combustion.
The determination of the inorganic carbon is
carried out in a separate furnace of the
module. Phosphoric acid is added to the
sample and the resulting CO 2 is purged at
200 °C and measured.
The SSM-5000A solid sample module does
not have its own detector, but is coupled to
the NDIR detector of the main instrument
(TOC-V or TOC-L). The detector is equipped
This is why different TOC limit values are with two coupled measuring cells that way to
specified for soil replacement and for complete the measurement of solids and
deposits in landfills. liquids consecutively without any additional
conversion.
