EDTA is the acronym for the chemical compoundethylenediaminetetraacetic acid.
EDTA refers to the chelating agent that is widely used to sequester di- and trivalent metalions such as magnesium ion in molecular biology.
EDTA features four carboxylic acid and two amine groups that can all bind to metals. EDTA forms specially strong complexes with Mn(II), Cu(II), Fe(III), and Co(III).[1]
To describe EDTA and its various protonated forms, chemists use a more cumbersome but more precise acronym that distinguishes between EDTA4−, the conjugate base that is the ligand, and H4EDTA, the precursor to that ligand.
Coordination chemistry principles
In coordination chemistry, H4EDTA is a member of the aminocarboxylate family of ligands that includes imidodiacetic acid ("H2IDA") and nitrilotriacetic acid ("H3NTA"). More specialized relatives include N,N'-ethylenediaminediacetic acid ("H2EDDA") and 1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid ("H4CyDTA"). These ligands are all formally derived from the amino acidglycine.
H4EDTA forms highly stable coordination compounds that are soluble in water. In these complexes, the ligand is usually either hexa- or pentadentate, EDTA4− or HEDTA3−, respectively. Such complexes are chiral, and [Co(EDTA)]− has been resolved into enantiomers.[2]
EDTA is used often in medical and laboratory equipment as an anticoagulant.
0.5 M EDTA Buffer Recipe Preparation
To make 0.5 M EDTA pH 8.0, you must mix the following.
For 1 liter add:
186.1 g Na2EDTA.2H2O
800 ml Milli-Q H2O
Adjust the pH to 8 with NaOH pellets (you will need about about 20 g) or NaOH solution.
The reason to adjust the pH is that the EDTA will not dissolve until the pH is about 8.
Bring volume up to 1 L with double distilled water (ddH2O), put in vessel or container, and autoclave.
References
↑ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
↑ Kirchner, S. Barium (Ethylenediaminetetracetato) Cobalt(III) 4-Hydrate" Inorganic Syntheses, McGraw-Hill: New York, 1957; Vol. 5, pages 186-188.
