NEMI Method Summary


Method Summary Information

Method Number:

2340C

Media:

WATER

Revision:

Standard Methods Online

Method Source:

Standard Methods

Subcategory:

INORGANIC

Analytes in this method

Official Name:

EDTA Titrimetric Method

Descriptive Name

EDTA Titrimetric Method (Hardness)

Source Info:

Standard Methods Online is jointly produced by the American Public Health Association (APHA), the American Water Works Association (AWWA), and the Water Environment Federation (WEF).
These organizations may be contacted by phone for more information on Standard Methods Online:
APHA: (301) 893-1894
AWWA: (800) 926-7337, (1-303-794-7711, outside U.S. / Canada)
WEF: (800) 666-0206 (1-703-684-2452 outside U.S. / Canada)

Citation:

Standard Methods Online

Brief Method
Summary:

A sample is titrated with EDTA at a pH of 10.0 +/- 0.1 using Eriochrome Black T or Calmagite indicator. Endpoint of red to blue.

Scope And
Application:

This method determines the harndess of a water sample.

Applicable
Conc Range:

None Provided.

Interferences:

Reduce interference from metal ions by adding MgCDTA. Interference from heavy metals or polyphosphates is reduced by other inhibitors, i.e., NaCN or Na₂S. Suspended or colloidal organic matter may also interfere with end point. Eliminate by evaporating the sample to dryness and heating in muffle furnace to oxidize organic matter.

QC Requirements:

None.

Sample Handling:

Conduct titration at or near normal room temperature.
Neutralize preserved sample to pH 7 with NaOH

Max Holding Time:

6 months after addition of nitric or sulfuric acid to pH <2

Relative Cost:

Less than $50

URL to obtain ordering information for this method:

http://www.standardmethods.org/

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Method Summary Information