In addition to being a familiar blood anticoagulant, EDTA is also a chelating agent and an important complexing agent. Although its function is far more than that, but today's focus is on some problems about its chelation with metal ions.
What are the characteristics of EDTA as a metal ion chelator?
1. EDTA forms complexes with metal ions and is quite stable.
2. The molar ratio of EDTA and most metal ions to form a complex is 1:1, and it is complexed with positive tetravalent zirconium and positive pentavalent molybdenum 1:2.
3. Most of the complexes formed by EDTA and metal ions are soluble in water.
4. The color of the formed complex is mainly determined by the color of the metal ion.
5. Most of the metal ions in the periodic table can form multiple pentacyclic chelates with EDTA.
Which tetrasodium EDTA and disodium are better used as chelating agents for metal ions?
In fact, it depends on the state of the metal ion to be chelated. Tetrasodium EDTA is suitable for chelating metal ions in acidic aqueous solutions; disodium EDTA is suitable for chelating metal ions in alkaline aqueous solutions and solid precipitation.
When EDTA forms a chelate with metal ions, what is the general chelation ratio?
EDTA and metal ions are complexed at 1:1
Why are most nucleases inhibited by the metal chelator EDTA?
Because most nucleases need the participation of Mg2+ to function. When the metal chelating agent EDTA is added, Mg2+ will be chelated, thereby inhibiting the activity of nuclease.
What is the mechanism of action of metal chelate EDTA?
EDTA and other synergists chelate with metal ions to prevent metal ions from catalyzing the auto-oxidation of substances. Antioxidants such as EMQ, BHA and BHT provide hydrogen atoms or directly combine with free radicals or peroxides to produce stable compounds to prevent substances The extension of the auto-oxidation chain.
Chelates are generally more stable than general complexes, and the five- or six-membered ring structure often in their structure enhances the stability. Because of this, the stability constants of chelates are very high, and many chelation reactions are carried out quantitatively and can be used for titration. The use of chelates can also mask metal ions.
The EDTA produced by Desheng Company is mainly in the form of sodium salt and potassium salt, and is mainly used as an anticoagulant for blood collection tube additives. But this does not prevent its use as a chelating agent. If we want to make it play a greater value, only we continue to understand more uses, grasp more information we don't understand, and continue to learn and explore.