News | April 4, 2014

Measuring The Organic Content In Geological Materials


Exeter Analytical reports that its Model 440 CHN Analyser provides a precise and accurate tool for determining the organic content of geological samples including soils, sediment and fossil fuels.

As the Model 440 provides complete control over combustion parameters it is able to reproducibly achieve 100% combustion with the widest range of geological sample types. Though incorporation of extensive automation in the Model 440 and intuitive software – the percentage Carbon (C), Hydrogen (H) and Nitrogen (N) in geological samples can be determined in as little as 5 minutes.

Determining the hydrocarbon content (Carbon and Hydrogen) of geological samples such as coal, peat and oil bearing rocks is a critical determinant of the value of the sample as a fuel material.  Analysing the percentage Carbon, Hydrogen and Nitrogen (CHN) content of soil samples is of major interest as the organic matter is known to directly influence the productive capacity of different soil types. Likewise determining the level of Carbon and Nitrogen in marine sediment is of great importance as the organic matter is known to have a direct effect on the health of the aquatic ecosystem.

In addition to organic content - geological samples typically also contain inorganic matter which is left as a residue after each CHN determination. The Exeter Analytical Model 440 is a static combustion CHN Elemental Analyser, with a unique horizontal furnace design, which enables easy removal of sample residue between each geological analysis.  Consequently one combustion tube will analyse in excess of 1000 geological samples without the need for removal and cleaning. By comparison other elemental analysers, employing vertical furnace designs, will require cleaning after as little as 20 samples. Because the Model 440 is able to effectively eliminate troublesome residue build-up, its gas flow characteristics are superior to other CHN Analysers leading to longer-term calibration stability as well as enhanced accuracy and precision for measured sample data.

SOURCE: Exeter Analytical (UK) Ltd.