Ethylenediaminetetraacetic acid

Ethylenediaminetetraacetic acid (EDTA) is an organic compound with the chemical formula C10H16N2O8, appearing as a white powder under normal temperature and pressure. It is a chelating agent capable of binding with divalent metal ions such as Mg²⁺, Ca²⁺, Mn²⁺, and Fe²⁺. Since many nucleases and some proteases require Mg²⁺ for their activity, EDTA is commonly used as an inhibitor of nucleases and proteases. It can also be employed to eliminate the inhibitory effects of heavy metal ions on enzymes.

EDTA is an important complexing agent with a wide range of applications. It is used as a bleaching and fixing agent in the processing of color photographic materials, a dyeing auxiliary, a fiber treatment agent, a cosmetic additive, a blood anticoagulant, a detergent, a stabilizer, and a polymerization initiator for synthetic rubber. As a representative chelating agent, EDTA can form stable water-soluble complexes with alkaline earth metals, rare earth elements, and transition metals. In addition to its sodium salt, EDTA also exists in various forms such as ammonium salts and salts of iron, magnesium, calcium, copper, manganese, zinc, cobalt, and aluminum, each serving different purposes. Furthermore, EDTA can be used to rapidly eliminate harmful radioactive metals from the human body, acting as a detoxifying agent. It is also employed as a water treatment chemical. Additionally, EDTA serves as an important indicator for titrating metals such as nickel and copper. To function as an indicator, it must be used together with ammonia water.