NEMI Method Summary

Method Summary Information

Method Number: 440.0 Media: WATER
Revision: Revision 1.4, September 1997
Method Source: U.S. EPA National Exposure Research Laboratory (NERL) [formerly EMSL]
Analytes in this method
Subcategory: INORGANIC
Official Name: Determination of Carbon and Nitrogen in Sediments and Particulates of Estuarine/Coastal Waters Using Elemental Analysis
Descriptive Name Elemental C and N by Combustion and Thermal Conductivity
Source Info: U.S.EPA National Exposure Research Laboratory (NERL)
Microbiological and Chemical Exposure Assessment Research Division (MCEARD)
[formerly the Environmental Monitoring Systems Laboratory (EMSL), Cincinnati, OH]
26 West Martin Luther King Drive
Cincinnati, Ohio 45268-0001
Fax: 513-569-7757
email: DWmethods.help@epa.gov
Citation: Methods for Determination of Chemical Substances in Marine and Estuarine Matrices - 2nd Edition (EPA/600/R-97/072)
58911 Byte file
Brief Method
Summary:
 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.
Scope And
Application:
 This method determines particulate carbon and particulate nitrogen in estuarine and coastal waters and sediment.
Applicable
Conc Range:
 The method is linear up to 4800 ug-C/sample, and 700 ug-N/sample.
Interferences:

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.
QC Requirements: 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.
Sample Handling: 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.
Max Holding Time:
 100 days.
 
Relative Cost: Less than $50
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