Ethylene Glycol Tetraacetic Acid (EGTA)

EGTA is an aminopolycarboxylic acid, a chelating agent. It is a colourless solid that is related to the better known EDTA. Compared to EDTA, it has a lower affinity for magnesium, making it more selective for calcium ions. It is useful in buffer solutions that resemble the environment in living cells[1] where calcium ions are usually at least a thousandfold less concentrated than magnesium. EGTA has also been used experimentally for the treatment of animals with cerium poisoning and for the separation of thorium from the mineral monazite. EGTA is used as a compound in elution buffer in the protein purification technique known as tandem affinity purification, in which recombinant fusion proteins are bound to calmodulin beads and eluted out by adding EGTA. EGTA is often employed in dentistry and endodontics for the removal of smear layer.