NEMI Method Summary


Method Summary Information

Method Number:

350.1

Media:

WATER

Revision:

Revision 2.0. August 1993

Method Source:

U.S. EPA National Exposure Research Laboratory (NERL) [formerly EMSL]

Analytes in this method

Subcategory:

INORGANIC

Official Name:

Nitrogen, Ammonia (Colorimetric, Automated Phenate)

Descriptive Name

Ammonia by Automated 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 Determination of Inorganic Substances in Environmental Samples (EPA/600/R-93/100)

255251

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Brief Method
Summary:

Alkaline phenol and hypochlorite react with ammonia to form indophenol blue that is proportional to the ammonia concentration. The blue color is intensified with sodium nitroprusside.

Scope And
Application:

This method determines ammonia in drinking, surface, and saline waters; domestic and industrial wastes.

Applicable
Conc Range:

0.01 - 2.0 mg/L (ammonia as N)

Interferences:

(A) Calcium and Magnesium: Ions of these metals can cause errors by precipitating during analyses. Use EDTA solution (for river and industrial waters) or potassium tartrate solution (for sea water) to reduce this interference.
(B) Turbidity: Sample turbidity should be removed by filtration.
(C) Color: Color absorbing in the range of the indophenol blue complex can interfere.

QC Requirements:

None.

Sample Handling:

Cool to 4^oC, add H₂SO₄ until sample pH < 2.

Max Holding Time:

28 days (MCAWW, Table 1).

Sample Prep Met

None.

Relative Cost:

Less than $50

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Method Summary Information