NEMI Method Summary

Method Summary Information

Method Number: 350.2 (Nesslerization) Media: WATER
Revision: Editorial Revision 1974
Method Source: U.S. EPA National Exposure Research Laboratory (NERL) [formerly EMSL]
Analytes in this method
Subcategory: INORGANIC
Official Name: Nitrogen, Ammonia (Colorimetric; Titrimetric; Potentiometric - Distillation Procedure)
Descriptive Name Ammonia by Colorimetry (Nesslerization)
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)
44855 Byte file
Brief Method
Summary:
 A sample is buffered at alkaline pH with borate buffer to decrease hydrolysis of cyanates and organic nitrogen compounds, and is distilled into a solution of boric acid. The ammonia distillate is determined colorimetrically by Nesslerization, or by other options given in the method.
Scope And
Application:
 This method determines ammonia, exclusive of Kjeldahl nitrogen, in drinking, surface, and saline waters; domestic and industrial wastes.
Applicable
Conc Range:
 0.05 - 1.0 mg/L ammonia as nitrogen (colorimetric)
Interferences: (A) Compounds 1: Many aromatics, aliphatic amines, and other compounds can cause turbidity upon reaction with Nessler reagent. Distillation is used prior to analysis to reduce/eliminate interferences.
(B) Compounds 2: Volatile alkaline compounds (some ketones, aldehydes, and alcohols) can effect Nesslerization. Some compounds (e.g., formaldehyde) can be removed prior to to distillation by boiling off at low pH.
(C) Cyanate: Cyanate can hydrolyze during distillation.
(B) Residual Chlorine: Remove residual chlorine using sodium thiosulfate.
QC Requirements: None.
Sample Handling: Cool to 4oC, add H2SO4 until sample pH < 2.
Max Holding Time:
 28 days (MCAWW, Table 1).
 
Relative Cost: Less than $50
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