Uses of EDTA
- In industry, EDTA is used to sequester metal ions, prevent color modification in dyed products, and inhibit the catalysis of hydrogen peroxide.
- In the food industry, EDTA is added as a preservative or stabilizer to prevent catalytic oxidative decoloration and formation of benzene.
- EDTA is used in water softeners to reduce water hardness and dissolve scale in boilers.
- It is used in cleaning solutions and in the cement industry for the determination of free lime and free magnesia.
- EDTA is used in agriculture for solubilizing iron ions in hydroponics and preventing the formation of insoluble iron salts in above neutral soils.
- Aqueous [Fe(EDTA)] is used for removing hydrogen sulfide and nitrogen oxides from gas streams.
- It is also used in photography to solubilize silver particles.
- EDTA was used in the separation of lanthanide metals by ion-exchange chromatography.
Medical and Laboratory Applications of EDTA
- Sodium calcium edetate is used in chelation therapy to bind metal ions and treat mercury and lead poisoning.
- It is used to remove excess iron from the body, especially in treating thalassemia.
- EDTA solutions are used in dentistry to remove inorganic debris and lubricate root canals.
- It is used as a preservative in ocular preparations and eyedrops.
- In medical diagnosis, EDTA is used to evaluate glomerular filtration rate and as an anticoagulant for blood samples.
- In biochemistry and molecular biology, EDTA is used to deactivate metal-dependent enzymes and suppress damage to DNA, proteins, and polysaccharides.
- It acts as a selective inhibitor against certain enzymes independently of metal ion chelation.
- In analytical chemistry, EDTA is used in complexometric titrations and analysis of water hardness.
- EDTA has specialised uses in biomedical labs, such as preventing the worsening of corneal ulcers in animals.
- It is used as an anticollagenase in veterinary ophthalmology.
Side effects and Environmental concerns of EDTA
- EDTA exhibits low acute toxicity with LD (rat) of 2.0g/kg to 2.2g/kg.
- It has been found to be both cytotoxic and weakly genotoxic in laboratory animals.
- Oral exposures have been noted to cause reproductive and developmental effects.
- Dermal exposure to EDTA in most cosmetic formulations would produce exposure levels below those seen to be toxic in oral dosing studies.
- Inhalation exposure to EDTA in aerosolised cosmetic formulations would also produce exposure levels below those seen to be toxic in oral dosing studies.
- EDTA is a persistent organic pollutant in the environment.
- Abiotic degradation of EDTA occurs slowly and mainly in the presence of sunlight.
- Direct photolysis is the most important process for the elimination of EDTA from surface waters.
- Biodegradation of EDTA can be achieved at about 80% using microorganisms in wastewater treatment plants.
- Alternative aminopolycarboxylates such as NTA, IDS, polyaspartic acid, EDDS, and MGDA are being investigated due to concerns about the biodegradability of EDTA.
Synthesis and Coordination Chemistry Principles of EDTA
- EDTA was first described in 1935 by Ferdinand Münz.
- It is mainly synthesised from ethylenediamine, formaldehyde, and sodium cyanide.
- This process is used to produce about 80,000 tonnes of EDTA each year.
- Impurities cogenerated by this route include glycine and nitrilotriacetic acid.
- EDTA is synthesised from ethylenediamine and chloroacetic acid.
- EDTA is a member of the aminopolycarboxylic acid family of ligands.
- It usually binds to a metal cation through its two amines and four carboxylates, making it a hexadentate chelating agent.
- Many resulting coordination compounds adopt octahedral geometry.
- EDTA complexes with Mn(II), Cu(II), Fe(III), Pb(II), and Co(III) form especially strong complexes.
- EDTA complexes have high affinity for metal cations and tend to be highly soluble in water.
Methods of Detection and Analysis of EDTA
- SRM-CE/MS is the most sensitive method for detecting and measuring EDTA in biological samples.
- SRM-CE/MS has a detection limit of 7.3ng/mL in human plasma and a quantitation limit of 15ng/mL.
- SRM-CE/MS can work with sample volumes as small as 7-8nL.
- HPLC can be used to measure EDTA in non-alcoholic beverages at a level of 2.0μg/mL.
Ethylenediaminetetraacetic acid (EDTA), also called edetic acid after its own abbreviation, is an aminopolycarboxylic acid with the formula [CH2N(CH2CO2H)2]2. This white, water-insoluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-soluble complexes even at neutral pH. It is thus used to dissolve Fe- and Ca-containing scale as well as to deliver iron ions under conditions where its oxides are insoluble. EDTA is available as several salts, notably disodium EDTA, sodium calcium edetate, and tetrasodium EDTA, but these all function similarly.
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| Names | |
|---|---|
| IUPAC name N,N′-(Ethane-1,2-diyl)bis[N-(carboxymethyl)glycine] | |
| Systematic IUPAC name 2,2′,2′′,2′′′-(Ethane-1,2-diyldinitrilo)tetraacetic acid | |
Other names
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| Identifiers | |
3D model (JSmol) | |
| Abbreviations | EDTA, H4EDTA |
| 1716295 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| DrugBank | |
| ECHA InfoCard | 100.000.409 |
| EC Number |
|
| 144943 | |
| KEGG | |
| MeSH | Edetic+Acid |
PubChem CID | |
| RTECS number |
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| UNII |
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| UN number | 3077 |
CompTox Dashboard (EPA) | |
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| Properties | |
| C10H16N2O8 | |
| Molar mass | 292.244 g·mol−1 |
| Appearance | Colourless crystals |
| Density | 0.860 g cm−3 (at 20 °C) |
| log P | −0.836 |
| Acidity (pKa) | 2.0, 2.7, 6.16, 10.26 |
| Thermochemistry | |
Std enthalpy of formation (ΔfH⦵298) | −1765.4 to −1758.0 kJ mol−1 |
Std enthalpy of combustion (ΔcH⦵298) | −4461.7 to −4454.5 kJ mol−1 |
| Pharmacology | |
| S01XA05 (WHO) V03AB03 (WHO) (salt) | |
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| Hazards | |
| GHS labelling: | |
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| Warning | |
| H319 | |
| P305+P351+P338 | |
| NFPA 704 (fire diamond) | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 1000 mg/kg (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). | |
ethylenediaminetetraacetic acid (uncountable)
