Direct Determination of Organic Carbon and Nitrogen in Marine Sediments

The filter based technique, using a Model 440 CHN Elemental Analyser from Exeter Analytical (UK), provides rapid and routine analysis of marine sediments, results are expressed in micrograms of Carbon and Nitrogen detected simplifying the calculation process. Analytical sensitivity is less than 1 microgram.

The Analytical Model 440 is a static combustion system, with a unique horizontal furnace design, which enables easy removal of filter and sample ash between each sediment analysis.  Consequently one combustion tube will analyse in excess of 1000 sediment samples without the need for removal and cleaning.  In addition the Model 440 provides the capacity to process filters up to 47 mm in diameter in one analytical cycle.  By comparison other elemental analysers, employing vertical furnace designs, need cleaning after as little as 20 samples and larger filters have to be sub sampled several times and then corrective calculations made to enable analysis.  Effectively eliminating troublesome residue build-up the gas flow characteristics of the Model 440 analyser are superior to other elemental analysers thereby providing longer-term calibration stability as well as enhanced accuracy and precision for measured sample data.

As the Exeter Analytical Model 440 provides complete control over combustion parameters it is able to reproducibly achieve 100% combustion with the widest range of sediment samples. For sediment samples with low levels of Nitrogen in the 0.1-0.2% range, proprietary Nitrogen analysis software uniquely enables accurate measurement at these levels with a high degree of accuracy.