NEMI Method Summary

Method Summary Information

Method Number: 353.3 Media: WATER
Revision: Issued 1974
Method Source: U.S. EPA National Exposure Research Laboratory (NERL) [formerly EMSL]
Analytes in this method
Subcategory: INORGANIC
Official Name: Nitrogen, Nitrate-Nitrite (Spectrophotometric, Cadmium Reduction)
Descriptive Name Nitrate-Nitrite by Cadmium Reduction and Colorimetry
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 the Chemical Analysis of Water and Wastes (MCAWW) (EPA/600/4-79/020)
57678 Byte file
Brief Method
Summary:
 Nitrate and nitrite: A filtered sample is passed through a column containing granulated copper-cadmium to reduce nitrate to nitrite. The nitrite (originally in the sample and reduced nitrate) is determined by diazotizing with sulfanilamide and coupling with N-(1-naphthyl)-ethylenediamine dihydrochloride to form a highly colored azo dye, which is measured with a spectrometer.
Nitrite alone: The procedure is the same except that the cadmium column is bypassed.
Scope And
Application:
 This method determines nitrite singly or nitrate and nitrite combined in drinking, surface, and saline waters, domestic and industrial wastes.
Applicable
Conc Range:
 0.01 to 1.0 mg/L Nitrate-nitrite nitrogen.
Interferences: (A) Suspended matter: Suspended materials will fowl the reduction column and restrict sample flow. Pretreat by filtering the sample through a 0.45 um filter or (for highly turbid samples) pretreating with zinc sulfate before filtration.
(B) Metals: Metals like iron or copper can produce low results. Treat samples with EDTA to remove this interference.
(C) Oil and grease: Oil and grease, that can coat the column and reduce efficiency should be removed by pre-extracting the sample with an organic solvent.
QC Requirements: None.
Sample Handling: If analysis can be made within 24 hours, refrigerating samples at 4oC is sufficient. If samples are kept more than 24 hours, preserve with 2 mL of sulfuric acid per liter of sample and refrigerate.
Do not preserve sample with mercuric chloride if they will be run through the reduction column.
Max Holding Time:
 28 Days (nitrate+nitrite)
48 hours (nitrate or nitrite, singly)
(MCAWW, Table 1).
Sample Prep Met None.
Relative Cost: Less than $50
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