ethylenediaminetetraacetic

Ethylenediaminetetraacetic acid, commonly abbreviated EDTA, is a polyamino carboxylic acid and a hexadentate chelating agent. It consists of an ethylenediamine backbone with four acetic acid groups, and in its fully deprotonated form it acts as Y4−, capable of binding multiple metal ions.

In solution, EDTA binds metal ions through its two amine nitrogens and four carboxylate oxygens, forming stable octahedral complexes with many divalent and some trivalent metals. Because EDTA has multiple protonation states, its chelating ability varies with pH, but at neutral or mildly basic conditions it effectively sequesters metal ions and prevents them from participating in catalytic or oxidative reactions.

Common forms and uses include salts such as disodium EDTA and tetrasodium EDTA, which are widely employed as chelating agents in medicine, laboratory settings, and consumer products. In healthcare, EDTA is used in chelation therapy to treat certain metal poisonings under medical supervision, and as an anticoagulant in blood collection tubes by binding calcium ions to prevent clotting. In laboratories, it is used to inhibit metal-dependent enzymes and to preserve DNA integrity by limiting divalent cations. In industry and foods, EDTA acts as a sequestrant to stabilize colors, flavors, and textures by binding trace metals, and it is also found in cosmetics and cleaning products.

Safety considerations include that EDTA is of low acute toxicity but can disrupt essential mineral balance if misused or consumed in excess. Proper handling and adherence to regulatory guidelines are important for its intended applications.