AAT Bioquest

What is the difference between EDTA and EGTA ?

Posted April 1, 2019


Both EDTA and EGTA are chelating agents. They are aminopolycarboxylic acids that have more or less the same properties.


Ethylenediaminetetraacetic acid (EDTA) is a chelating agent consisting of six binding sites. It has the capacity to bind and sequester a variety of metal ions (except for alkali metals) such as Ca2+, Mg2+ and Fe2+. EDTA combines with all cations in a 1:1 ratio regardless of the charge on the cation. In laboratory applications, EDTA can be used as a preservative for biological samples. It scavenges for trace amounts of metal ions and prevents them from catalyzing air oxidation in the samples. EDTA has a higher affinity for Mg2+ ions compared to EGTA.


Ethylene glycol tetraacetic acid (EGTA) is also a chelating agent. Compared to EDTA, it has a higher affinity for calcium ions but a lower affinity for magnesium ions.  Similar to EDTA, EGTA can be used as a buffer to resemble the pH of a living cell. This property of EGTA permits its usage in Tandem Affinity Purification, which is a protein purification technique. EGTA has a higher boiling point than EDTA.

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