Disodium EDTA has the chemical formula of
[CH2N(CH2CO2H)2]2, the molecular formula of C10H16N2O8, and is a major chelating agent from which all of its applications extend from. It has high affinity to free metal ions, a common pollutant and impurity in many chemical environments. As an example, when we clean something with soap or wash our laundry, there is a chemical reaction between the detergent, the organic dirt, and the water that provides an aqueous solution environment for the chemical reaction of “cleaning” to occur. However, many impurities and free metal ions and minerals in tap water makes the performance of detergents less effective and inconsistent across geographies with varying water quality. Disodium EDTA as a chelating agent helps bind the free radicals and impurities, allowing the major ingredients in detergents to work effectively and consistently without excessive “chemical disturbance.”
Disodium EDTA has limited solubility in water, but at a typical usage rate of 0.2% to improve preservative efficacy, even if not fully solubilized, it is still efficacious. In creams or lotions, there will be no grittiness and it will not be seen. In clear or transparent gel, serum, or clear surfactant systems, use Tetrasodium EDTA, which is highly soluble in water. At low usage rates, it will not raise the pH unduly, but if it does, you can simply lower the pH of your formulation with a citric acid solution.