The acronym
EDTA refers to the compound
ethylene diamine tetraacetic acid. This compound, or its disodium salt, is a well known
chelating agent, forming
coordination compounds with many divalent
metal ions, but especially
calcium(Ca
2+) and
magnesium(Mg
2+). As a result, this compound is used extensively in the
laboratory, to scavenge metal ions, in metal ion
titrations, and as a component of
buffer solutions. It is used in water quality work, to determine water hardness and as a water softener. It has use in medicine, as an
anticoagulant, and in industry, as a food
preservative. There is a therapy, perhaps controversial, that has evolved around metal scavengers of this kind, called
chelation therapy[?].