Ethylenediaminetetraacetic acid disodium salt dihydrate

Product No. E5134

Store at Room Temperature

Product Description

Molecular Formula: C10H14N2Na2O8 • 2H2O
Molecular Weight: 372.2
CAS Number: 6381-92-6
Melting Point: 248 °C
pKa: 2.0, 2.7, 6.2, 10.31

Synonyms: EDTA, (Ethylenedinitrilo)tetraacetic acid

This product is designated as Molecular Biology grade and is suitable for molecular biology applications. It has been analyzed for the presence of nucleases and proteases.

EDTA is an inhibitor of metalloproteases, at effective concentrations of 1-10 μM. EDTA acts as a chelator of the zinc ion in the active site of metalloproteases, and can also inhibit other metal ion-dependent proteases such as calcium-dependent cysteine proteases. EDTA may interfere with biological processes which are metal-dependent.2

For use as an anticoagulant, disodium or tripotassium salts of EDTA are most commonly used. The optimal concentration is 1.5 mg per ml of blood. EDTA prevents platelet aggregation and is, therefore, the preferred anticoagulant for platelet counts.3 Using a 2% EDTA solution, 1-2 drops per ml of whole blood can be used as an anticoagulant.

A procedure for a chromogenic assay of EDTA has been published.4

Precautions and Disclaimer

This product is for R&D use only, not for drug, household, or other uses. Please consult the Safety Data Sheet for information regarding hazards and safe handling practices.

Preparation Instructions

This product is slowly soluble in water at room temperature up to 0.26 M, which is approximately 96 mg in a final volume of 1 ml. The pH of this solution will be in the range of 4 to 6. EDTA salts are more soluble in water as the pH increases: the more EDTA there is in the salt form, the higher the pH of a water solution, and therefore, the higher the room temperature solubility. This can be achieved by a gradual addition of concentrated sodium hydroxide solution to the EDTA solution.


A stock solution of 0.5 M at pH 8.5 is stable for months at 4 °C.2

Solutions of EDTA may be autoclaved.




  1. Data for Biochemical Research, 3rd ed., Dawson, R. M. C., et al., Oxford University Press (New York, NY: 1986), p. 404.
  2. Proteolytic Enzymes: A Practical Approach, 2nd ed., Beynon, R. and Bond, J. S., eds., Oxford University Press (Oxford, UK: 2001), p. 322.
  3. Clinical Hematology: Principles, Procedures, Correlations. ed. Lotspeich-Steininger, C. A., et al., Lippincott (Philadelphia, PA: 1992), p. 18.
  4. Sorensen, K., An Easy Microtiter Plate-based Chromogenic Assay for Ethylenediaminetetraacetic Acid and Similar Chelating Agents in Biochemical Samples. Anal. Biochem., 206(1), 210-211 (1992).


GCY/RXR 11/02

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