NEMI Method Summary

Method Summary Information

Method Number: D3113B Media: WATER
Revision: Reapproved 1998.  Current edition approved Nov. 15, 1992. Published January 1993. Originally publish
Method Source: ASTM International
Subcategory: INORGANIC Analytes in this method
Official Name: Standard Test Methods for Sodium Salts of EDTA in Water
Descriptive Name EDTA: Unchelated Sodium Salt of EDTA (Method B)
Source Info: ASTM International
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Citation: ASTM Volume 11.02
 
Brief Method
Summary:
 The unchelated EDTA is titrated with a standard magnesium solution to a purple or reddish color with chrome black T indicator.
Scope And
Application:
 This test method may be applied to waters containing unchelated EDTA in concentrations of 1 to 50 mg/L. Higher concentrations may be determined by diluting the sample.
Applicable
Conc Range:
 1 to 50 mg/L
Interferences: Iron, copper, and manganese cause decolorization or may otherwise interfere with the color change of the indicator.
Heavy metal EDTA complexes may undergo oxidation by the atmosphere, resulting in the release of EDTA which will be titrated in the procedure.
Other chelating agents may react the same as EDTA.
Aluminates in the sample may be converted to aluminum ion (Al+3) during the titration that would complex with any unchelated EDTA resulting in erroneously low values.
QC Requirements: Before this test method is applied to the analysis of samples of unknown Na2EDTA concentrations, the analyst must establish quality control by the procedures recommended in Practice D 4210 and Guide D 3856.
A duplicate sample and known standard must be analyzed each day that an analysis is performed. The duplicate and standard shall meet the limits as established by the control chart before a determination is considered satisfactory.
A blank and a spiked sample shall be analyzed each day that an analysis is performed. Spiking shall be in accordance with that outlined in 11.11 of Guide D 3856. The blank shall be low enough that it will not unduly influence the data.
One sample must be analyzed in duplicate with each group of 10 or less samples. The results must meet the criteria established in this test method before the data for that batch or set of 10 samples is acceptable.
Sample Handling: Collect the samples in accordance with Practice D 1066 or Practices D 3370 as applicable.
Max Holding Time:
 Because of possible oxidation or decomposition of some components of aqueous samples, the lapse of time between collection of samples and start of analysis should be kept to a minimum (no longer than 15 min).
 
Relative Cost: Unknown
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