Ethylenediaminetetracetic Acid EDTA

In a complexation reaction, the reaction unit is an electron pair. For the metal, the number of reaction units is the number of coordination sites available for binding ligands. For the ligand, the number of reaction units is equivalent to the number of electron pairs that can be donated to the metal. One of the most important analytical complexation reactions is that between the ligand ethylenediaminetetracetic acid (EDTA), which can donate 6 electron pairs and 6 coordinate metal ions, such as Cu thus... 

Ligno sulfonate—metal complexes are weaker complexes than those formed from amine-based complexing agents such as ethylenediaminetetracetic acid (EDTA). They are compatible with most pesticides /herbicides, but thek use in phosphate fertilisers is not recommended. 

Why is it advisable to add ethylenediaminetetracetic acid (EDTA) to measure calcium when it is in the form of a phosphate ... 

Among the numerous commercial derivatives of ethylenediaminetetracetic acid (EDTA), a mixed salt of Zn, Na containing one atom of zinc and two atoms of sodium per molecule of EDTA is found. This mixed salt presents itself in the form of a crystallised hydrate. An attempt is described to deduce the number of water molecules of this hydrate by measuring the presence of zinc by atomic absorption. The experimental approach was as follows ... 

Ethylenediaminetetracetic acid (EDTA), usually as the di-sodium salt, is added to a concentration of 1 mM to chelate heavy metal ions, which can inhibit enzymes at very low concentrations, and also to remove Ca2+ and Mg2+, which can otherwise act... 

The transformation between linear and circular tpy-DNA structures was dependent on the M /tpy stoichiometry and the relative stability of [M(tpy)] +, [M(tpy)2] ", and the metal complexes with other chelating agents. For example, the linear-to-circular transformation of tpy-modified DNA induced by 1 equiv of Zn " " could be reversed by a second equivalent of Zn +, which transformed the [Zn(tpy)2l complex into two terminal [Zn(tpy)] complexes [Fig. 16(b)] (148). Also, addition of ethylenediaminetetracetic acid (EDTA), which has a... 

The low molecular weight sodium salts of ethylenediaminetetracetic acid (EDTA) and nitrilotriacetic acid (NTA) soluble in water, are effective in the control of scaling in steam raising equipment. The action of these additives is to form complex ions with calcium and magnesium hardness. The action of EDTA is similar to ion exchange, and may be described by the simplified equation ... 

Chelate ligands can also be polydentate, as in tridentate 1.4 and hexadentate 1.5. As a tridentate ligand, 1.4 is termed a pincer ligand, a type attracting much recent attention. Ethylenediaminetetracetic acid, (EDTA, 1.5) can take up all six sites of an octahedron and thus completely wrap up many different metal ions. As a common food preservative, EDTA binds free metal ions so that they can no longer catalyze aerial oxidation of the foodstuff. Reactivity in metal complexes usually requires the availability of open sites or at least labile sites at the metal. 

Iron-deficiency in fruit trees (citrus and pomes) causes poor crops. A soil may be rich in iron, and yet so basic that the iron is not available to the rootlets. Ethylenediaminetetracetic acid (EDTA), sprayed on such soil, extracts iron by forming the EDTA-ferric complex, which is absorbed by the rootlets. Experiments with tomato plants, grown in an iron-EDTA medium labelled with Fe, and with in the 2-position of the acetate-group, showed that the plant absorbs the intact complex, which is translocated. Later, the organic part is broken down by metabolism which leaves the inorganic iron (Hill-Cottingham and Lloyd-Jones, 1961). When soil is poor in iron, ferric EDTA is sprayed on the ground with the same result. 

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