Nitrilotriacetic acid

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Nitrilotriacetic acid
Skeletal formula of nitrilotriacetic acid
Preferred IUPAC name
2,2′,2″-Nitrilotriacetic acid[citation needed]
Systematic IUPAC name
2-[Bis(carboxymethyl)amino]acetic acid[2]
Other names
139-13-9 YesY
ChEBI CHEBI:44557 YesY
ChemSpider 8428 YesY
DrugBank DB03040 YesY
EC Number 205-355-7
Jmol 3D model Interactive image
Interactive image
KEGG C14695 N
MeSH Nitrilotriacetic+Acid
PubChem 8758
RTECS number AJ0175000
UN number 2811
Molar mass 191.14 [3]
Appearance White crystals
Melting point 246[3] °C (475 °F; 519 K)
Insoluble. <0.01 g/100 mL at 23℃ [3]
−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
H302, H319, H351
P281, P305+351+338
Harmful Xn
R-phrases R22, R36, R40[3]
S-phrases S26, S36/37/39, S45[3]
Flash point 100 °C (212 °F; 373 K)
Lethal dose or concentration (LD, LC):
1.1 g kg−1 (oral, rat)
Related compounds
Related alkanoic acids
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
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+.[4]

Production and use[edit]

Nitrilotriacetic acid 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.[5]

The acid is also cogenerated as an impurity in the synthesis of EDTA, arising from reactions of the ammonia coproduct.[6]

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.[5] NTA is a tripodal tetradentate trianionic ligand.[7] 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 purification of proteins containing a tag consisting of six histidine residues at either terminus.[8]


  1. ^ Nitrilotriacetic acid
  2. ^ "Nitrilotriacetic Acid - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification. Retrieved 13 July 2012. 
  3. ^ a b c d e ChemBK Chemical Database
  4. ^ NITRILOTRIACETIC ACID AND ITS SALTS, International Agency for Research on Cancer (IARC)
  5. ^ 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 
  6. ^ Hart, J. Roger (2005) "Ethylenediaminetetraacetic Acid and Related Chelating Agents" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim. doi:10.1002/14356007.a10_095
  7. ^ 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
  8. ^ qiaexpressionist