NEMI Method Summary


Method Summary Information

Method Number:

425.1

Media:

WATER

Revision:

Issued 1971

Method Source:

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

Analytes in this method

Subcategory:

ORGANIC

Official Name:

Methylene Blue Active Substances (MBAS) (Colorimetric)

Descriptive Name

Surfactants by 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)

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Brief Method
Summary:

Methylene blue reacts with anionic-type surface active materials to form a blue colored sample. The salt is extracted with chloroform and intensity of the color in the extract is proportional to the concentration of methylene blue active substances (surfactants).

Scope And
Application:

This method determines methylene blue active substances (surfactants) in drinking water, surface water; domestic and industrial wastes. The method is not applicable to saline waters.

Applicable
Conc Range:

0.025 to 100 mg/L linear alkyl sulfonate.

Interferences:

Compounds: Many compounds other than surfactants can react with methylene blue, including organically bound sulfates, sulfonates, carboxylates, phosphates, phenols, cyanates, thiocyanates, and some inorganic ion such as nitrates and chlorides. However, the occurrence of these compounds is usually rare (with the exception of chlorides).

QC Requirements:

None.

Sample Handling:

None.

Max Holding Time:

48 Hours (MCAWW, Table 1).

Sample Prep Met

None.

Relative Cost:

Less than $50

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Method Summary Information