Nitrilotriacetic acid

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Nitrilotriacetic acid
Skeletal formula of nitrilotriacetic acid
CAS number 139-13-9 YesY
PubChem 8758
ChemSpider 8428 YesY
EC number 205-355-7
UN number 2811
DrugBank DB03040
KEGG C14695 N
MeSH Nitrilotriacetic+Acid
ChEBI CHEBI:44557 YesY
RTECS number AJ0175000
Beilstein Reference 1710776
Gmelin Reference 3726
Jmol-3D images Image 1
Image 2
Molecular formula C6H9NO6
Molar mass 191.14 g mol−1
Appearance White crystals
Std enthalpy of
−1.3130–−1.3108 MJ mol−1
GHS pictograms The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word WARNING
GHS hazard statements H302, H319, H351
GHS precautionary statements P281, P305+351+338
EU classification Harmful Xn
R-phrases R22, R36, R40
S-phrases S26, S36/37
Flash point 100 °C (212 °F; 373 K)
LD50 1.1 g kg−1 (oral, rat)
Related compounds
Related alkanoic acids
Related compounds
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Nitrilotriacetic acid (NTA) is the aminopolycarboxylic acid with the formula N(CH2CO2H)3. It is a colourless solid that is used as a chelating agent, which forms coordination compounds with metal ions (chelates) such as Ca2+, Cu2+, and Fe3+.[3]

Production and use[edit]

This compound is commercially available as the free acid and as the sodium salt. It is produced from ammonia, formaldehyde, and sodium cyanide or hydrogen cyanide. Worldwide capacity is estimated at 100 thousand tonnes per year.[4]

Coordination chemistry and applications[edit]

The uses of NTA are similar to that of EDTA, both being chelating agents. In contrast to EDTA, NTA is easily biodegradable and is almost completely removed during wastewater treatment. It is used for water softening and as a replacement to sodium and potassium triphosphate in detergents, and cleansers.[4] NTA is a tripodal tetradentate trianionic ligand.[5] In the laboratory, this compound is used in complexometric titrations. A variant of NTA is used for protein isolation and purification in the His-tag method. The modified NTA is used to immobilize nickel to a solid support. This allows separation of proteins containing "tag" containing six histidine residues at either terminus.[6]


  1. ^ "Nitrilotriacetic Acid - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification. Retrieved 13 July 2012. 
  2. ^ Nitrilotriacetic acid
  3. ^ NITRILOTRIACETIC ACID AND ITS SALTS, International Agency for Research on Cancer (IARC)
  4. ^ a b Charalampos Gousetis, Hans-Joachim Opgenorth (2005), "Nitrilotriacetic Acid", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a17_377 
  5. ^ B. L. Barnett, V. A. Uchtman "Structural investigations of calcium-binding molecules. 4. Calcium binding to aminocarboxylates. Crystal structures of Ca(CaEDTA).7H2O and Na(CaNTA)" Inorg. Chem., 1979, volume 18, pp 2674–2678. doi:10.1021/ic50200a007
  6. ^ qiaexpressionist