Nitrilotriacetic acid

• Tris (carboxymethyl ) amine
• N, N- bis (carboxymethyl ) glycine
• I complexone
• I Titriplex
• I Chelaplex

Colorless crystals

Fixed

241.5 ° C ( decomposition)

• PKS1: 1.9
• PKS2: 2.5
• PKS3: 9.7

Very poor in water ( 1.28 g · l-1 at 20 ° C)

Attention

1100 mg · kg -1 ( LD50, rat, oral)

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Nitrilotriacetic acid or short- NTA is a complexing agent. In aqueous solution, NTA forms stable complexes with metal ions.

Properties

NTA forms with metal ions such as Ca2 , Cu2 , Ni2 or Fe3 stable complexes.

Use

NTA is partially used for water softening. The use as an additive in detergents enthärtender has declined despite the biodegradability of NTA in sewage treatment plants in recent years, as you look at the dissolving power of heavy metals as problematic. In analytical chemistry, it is known as the chelate is used in the I and complexometry for determining metal ions. Furthermore, it is in the affinity chelating ligands (usually with Ni2 as central ion ) used for the purification of poly -histidine -tagged proteins. In the year 1999 20.000 tons NTA were consumed in Europe.

Biological Significance

It has long been suspected that NTA can mobilize heavy metals from the sediment in the aquatic environment. In practice this is not the case, as NTA is present as solid calcium complex in natural waters. As can be seen in the safety instructions is (R40 ), it is suspected that this substance has carcinogenic.

Proof

NTA can be detected with copper sulfate solution and complex indicator.