dEDTA

dEDTA, short for disodium ethylenediaminetetraacetate, is the disodium salt form of ethylenediaminetetraacetic acid (EDTA). It is a widely used chelating agent that binds metal ions such as calcium, magnesium, iron, and other divalent or trivalent metals to form stable, soluble complexes. In solution, dEDTA is typically present as Na2EDTA or related salts, with the acid form H4EDTA being deprotonated at higher pH.

Chemistry and properties: The chelating ability of dEDTA arises from its four acetic acid arms and two amine nitrogens, allowing it to form octahedral complexes with metal ions. The binding strength and speciation depend on pH, which influences the degree of deprotonation and the particular metal ion involved. Different salt forms (such as disodium or tetrasodium EDTA) affect solubility and buffering behavior in solutions used for various applications.

Applications: In molecular biology and biochemistry, dEDTA is used to inhibit metal-dependent nucleases and stabilize nucleic acids in extraction and storage buffers. Clinically, EDTA salts serve as anticoagulants in blood collection tubes by chelating calcium. In dentistry, EDTA-based solutions (often around 15–17%) are used to remove the smear layer from dentin during endodontic procedures. In cosmetics, foods, and detergents, EDTA salts act as sequestrants to prevent metal-catalyzed oxidation and preserve product quality. In industrial and water-treatment contexts, dEDTA helps control metal ions to prevent scale and corrosion.

Safety and environmental aspects: dEDTA has relatively low acute toxicity but can bind essential minerals, potentially affecting human health and ecosystems if misused. It is fairly persistent in the environment and can mobilize heavy metals under certain conditions, making proper handling and disposal important.