Determination of Organic Carbon and Nitrogen in Marine Sediment

An optimised technique for direct determination of organic carbon and nitrogen in marine sediment is now available from Exeter Analytical (UK).

The filter based technique, using an Exeter Analytical Model 440 CHN Elemental Analyser, provides rapid and routine analysis of marine sediment. Results are expressed in micrograms of Carbon and Nitrogen detected simplifying the calculation process. Analytical sensitivity is less than 1 microgram.

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

The 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, will require cleaning after as little as 20 samples. Further, larger filters have to be sub sampled several times and corrective calculations made to enable analysis. The gas flow characteristics of the Model 440 analyser are superior to other elemental analysers due to the effective elimination of troublesome residue build-up. This thereby provides longer-term calibration stability as well as enhanced accuracy and precision for measured sample data.