The potential of temperature-dependent carbon differentiation for soil analysis

Dr. Fabian Alt1, Almut Loos1, Dr. Christine Hallgren2, Dr. Lutz Lange1

1Elementar Analysensysteme GmbH, Langenselbold, Germany, 2Elementar Australia Pty Ltd, Sydney, Australia

Detailed information about carbon contents, fractions, and pools in soils are essential for understanding biogeochemical processes and the consequences for land use, waste management, and climate change. The methodological challenge in the determination of carbon fractions is the accurate differentiation of organic, inorganic and in particular elemental carbon. Additionally, it is important to understand the soil organic carbon (SOC) storage and degradation processes. Therefore, knowledge about the SOC stability and association is highly beneficial.

We tested the advantages and drawbacks of a temperature gradient program with different hold times compared to classic direct and indirect methods for the determination of carbon fractions and species (e.g., EN 15936).

The soli TOC® cube of Elementar Analysensysteme GmbH has been used for comparison measurements of different soils, waste as well as pure substances. It offers the opportunity to run a free configurable temperature program due to its dynamic heater and catalytic post combustion. Accordingly, carbon compounds are combusted and transformed to CO2 due to their thermal stability at different temperatures and the CO2 is detected. Also, different carrier gases have been tested for separating elemental and inorganic carbon under oxidative and pyrolytic conditions.

For most soils, the organic carbon fractions determined by the direct procedure, match the sum of elemental and organic carbon according to the temperature ramping program. The differentiation of organic and elemental carbon is  determined by using a temperature of 400°C for splitting these fractions. Furthermore, the flexibility of the temperature gradient offers more opportunities for a reliable and accurate separation of carbon fractions and possibly even species. Consequently, there are more options for special samples and research questions compared to acidification and combustion methods, which use only one temperature above 900°C.


Biography:

  • Studied Chemistry in Frankfurt and Heidelberg University
    • Diploma Thesis in Environmental Geosciences
  • Dissertation (PhD) at Max-Planck-Institute for Chemistry in Mainz (Germany) and Utrecht University (the Netherlands)
    • Atmospheric Sciences: Exchange processes between the lowermost stratosphere and the upper troposphere.
  • Post Doc at Max Planck Institute for Chemistry in Mainz
  • 2005: Produktmanager at Elementar (Elemental Analysis and IRMS)
  • 2011 Director for R&D and innovation management
  • 2017: Director Global Sales and Marketing
  • August 2019: move to Elementar Australia

SOIL ORGANIC MATTER

7th International Symposium
Soil Organic Matter

6 – 11 October 2019

Hilton Adelaide

Adelaide, South Australia

Australia

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