EPA-NERL: 440.0: Elemental C and N by Combustion and Thermal Conductivity
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Official Method Name
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Determination of Carbon and Nitrogen in Sediments and Particulates of Estuarine/Coastal Waters Using Elemental Analysis |
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Current Revision
| Revision 1.4, September 1997 |
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Media
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WATER |
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Instrumentation
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Elemental Analyzer |
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Method Subcategory
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Inorganic |
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Method Source
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Citation
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Brief Method Summary
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A weighed amount of dried particulate (from water) or sediment is combusted at a high temperature using an elemental analyzer. The combustion products are passed over a copper reduction tube to covert nitrogen oxides to molecular nitrogen. Carbon dioxide, nitrogen, and water vapor are mixed at a known volume, temperature, and pressure. The concentrations of nitrogen and carbon are determined using a series of thermal conductivity detectors/traps, measuring in turn by difference hydrogen (as water vapor), carbon (as carbon dioxide), and nitrogen (as molecular nitrogen). Procedures also are provided to differentiate between organic and inorganic carbon, if desired. |
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Scope and Application
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This method determines particulate carbon and particulate nitrogen in estuarine and coastal waters and sediment. |
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Applicable Concentration Range
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The method is linear up to 4800 ug-C/sample, and 700 ug-N/sample. |
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Interferences
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Contamination: Contamination from carbon and nitrogen compounds on laboratory surfaces, fingers, in detergents and dusts are minimized by using gloves and forceps when handling samples. |
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Quality Control Requirements
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Initial demonstration of laboratory capability and the continued analysis of laboratory reagent blanks, laboratory duplicates, field duplicates, and calibration standards analyzed as samples as a continuing check on performance. |
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Sample Handling
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Samples are collected using hydrocast or submersible pump systems and filtered immediately as described in Section 11.1.1 of the method. Store the filtered sample pads by freezing at -20oC or storing in a desiccator after drying at 103-105oC for 24 hours. If storage of water sample is necessary, place the sample into a clean amber bottle at store at 4oC until filtration is done. |
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Maximum Holding Time
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100 days. |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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