EDTA

EDTA

This is a computer generated image of EDTA's 3-dimensional structure. Red molecules are hydrogen, blue molecules are oxygen, green molecules are nitrogen, and grey molecules are carbon.

EDTA is the chemical compound ethylenediaminetetraacetic acid, otherwise known as edetate, versene, or diaminoethanetetraacetic acid disodium salt. EDTA or its disodium salt is a chelating agent, forming coordination compounds with most divalent (or trivalent) metal ions, such as calcium (Ca²⁺) and magnesium (Mg²⁺) or copper (Cu²⁺). It is also a hydrophilic compound and its recommended storage is in a dry area with a desiccator. EDTA has a molecular mass of 292.28 g/mol.

Its CAS number is 60-00-4[1] and its SMILES structure is OC(CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O)=O.

Uses

• Scavenging metal ions. In biochemistry and molecular biology, this is a common method to inactivate enzymes.
• Complexometric titrations.
• Buffer solutions.
• Determination of water hardness.
• Use as a water softener.
• Used in medicine as a treatment (brand name Endrate®, marketed by Hospira, Inc.; generic product is also on the market) for acute hypercalcemia and lead poisoning.
• Used in medical and laboratory equipment as an anticoagulant.
• Added to some processed foods and especially cosmetics as a preservative and a sequestrant.
• A somewhat controversial therapy, called chelation therapy has evolved around metal scavengers such as EDTA.
• Used in dentistry as a root canal irrigant to remove compounds of organic and inorganic debris (smearlayer)
• Used in photography as a component of bleach-fix used to dissolve elemental silver produced during development.
• Used as a soil conditioner to allow calcifuge plants to grow in base rich soils.
• Used as an anti-sulfating agent in car batteries
• Used in coca-cola and other sodas to prevent accidental contamination

Use as an anticoagulant

Metal-EDTA chelate

EDTA works as an anticoagulant by chelating all the calcium contained in blood since calcium is needed for coagulation to occur. The calcium levels below which clotting ceases are low enough to be lethal, so EDTA is only used as an anticoagulant outside the body; for instance in tubes of blood, and medical machinery.

EDTA is contained in purple, lavender and pink Vacutainer (tubes that blood is taken in), and can be in the form of a powder, or a small amount of liquid, already in the tube.

The sodium or potassium salts of EDTA (K₂EDTA, K₃EDTA, Na₂EDTA) are used in Vacutainer tubes. This means levels of these ions are increased, and detectable levels of calcium and magnesium are decreased. For this reason many clinical chemistry tests are not done using plasma from EDTA tubes.

Trivia

• EDTA played a central role in O.J. Simpson trial when one of the blood samples collected from O.J. Estate was found to contain traces of the compound. This was used by the defense to indicate that the sample had been planted from one of the vials collected during the investigation. Prosecution claimed EDTA might have appeared in the sample as a result of eating McDonald's foods (either through bloodstream or, more likely, via contamination of blood flowing over the hand used in grabbing the food)
• ethylenediaminetetraacetates is the longest hypothetically legal Scrabble word (hypothetical because it exceeds 15 letters, the width of a Scrabble board) in North American play

See also

• EGTA
• BAPTA

External links

• pH-Spectrum of EDTA complexes
• EDTA: Molecule of the Month

The content of this page is retrieved from http://en.wikipedia.org/wiki/EDTA under GFDL