EDTA
Overview
 
Ethylenediaminetetraacetic acid, widely abbreviated as EDTA (for other names, see Table), is a polyamino carboxylic acid
Polyamino carboxylic acid
thumb|left|120px|a metal complex with the [[EDTA]] anionthumb|120px|the [[glycine|glycinate]] ion can form a chelate complex with a metal ionthumb|120px| β [[alanine]]...

 and a colourless, water-soluble solid. Its conjugate base is named ethylenediaminetetraacetate. It is widely used to dissolve limescale
Limescale
Limescale is the hard, off-white, chalky deposit found in kettles, hot-water boilers and the inside of inadequately maintained hot-water central heating systems...

. Its usefulness arises because of its role as a hexadentate ("six-toothed") ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

 and chelating agent, i.e. its ability to "sequester" metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s such as Ca2+ and Fe3+.
Discussions
Encyclopedia
Ethylenediaminetetraacetic acid, widely abbreviated as EDTA (for other names, see Table), is a polyamino carboxylic acid
Polyamino carboxylic acid
thumb|left|120px|a metal complex with the [[EDTA]] anionthumb|120px|the [[glycine|glycinate]] ion can form a chelate complex with a metal ionthumb|120px| β [[alanine]]...

 and a colourless, water-soluble solid. Its conjugate base is named ethylenediaminetetraacetate. It is widely used to dissolve limescale
Limescale
Limescale is the hard, off-white, chalky deposit found in kettles, hot-water boilers and the inside of inadequately maintained hot-water central heating systems...

. Its usefulness arises because of its role as a hexadentate ("six-toothed") ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

 and chelating agent, i.e. its ability to "sequester" metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

 ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...

s such as Ca2+ and Fe3+. After being bound by EDTA, metal ions remain in solution but exhibit diminished reactivity. EDTA is produced as several salts, notably disodium EDTA and calcium disodium EDTA.

Synthesis

The compound was first described in 1935 by Ferdinand Munz, who prepared the compound from ethylenediamine and chloroacetic acid
Chloroacetic acid
Chloroacetic acid, industrially known as monochloroacetic acid is the organochlorine compound with the formula ClCH2CO2H. This carboxylic acid is a useful building-block in organic synthesis.-Production:...

. Today, EDTA is mainly synthesised from ethylenediamine (1,2-diaminoethane), formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

, and sodium cyanide
Sodium cyanide
Sodium cyanide is an inorganic compound with the formula NaCN. This highly toxic colorless salt is used mainly in gold mining but has other niche applications...

. This route yields the sodium salt, which can be converted in a subsequent step into the acid forms:
H2NCH2CH2NH2 + 4 CH2O + 4 NaCN + 4 H2O → (NaO2CCH2)2NCH2CH2N(CH2CO2Na)2 + 4 NH32NCH2CH2N(CH2CO2Na)2 + 4 HCl → (HO2CCH2)2NCH2CH2N(CH2CO2H)2 + 4 NaCl

In this way, about 80M kilograms are produced each year. Impurities cogenerated by this route include glycine
Glycine
Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...

 and nitrilotriacetic acid
Nitrilotriacetic acid
Nitrilotriacetic acid , C6H9NO6, is a polyamino carboxylic acid and is used as a chelating agent which forms coordination compounds with metal ions such as Ca2+, Cu2+ or Fe3+.The uses of NTA are similar to that of EDTA...

; they arise from reactions of the ammonia coproduct.

Nomenclature

To describe EDTA and its various protonated forms
Protonation
In chemistry, protonation is the addition of a proton to an atom, molecule, or ion. Some classic examples include*the protonation of water by sulfuric acid:*the protonation of isobutene in the formation of a carbocation:2C=CH2 + HBF4 → 3C+ + BF4−*the protonation of ammonia in the...

, chemists distinguish between EDTA4−, the conjugate base that is the ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

, and H4EDTA, the precursor
Precursor (chemistry)
In chemistry, a precursor is a compound that participates in the chemical reaction that produces another compound. In biochemistry, the term "precursor" is used more specifically to refer to a chemical compound preceding another in a metabolic pathway....

 to that ligand. At very low pH (very acidic conditions) the fully protonated H6EDTA2+ form predominates, whereas at very high pH or very basic condition, the fully deprotonated Y4− form is prevalent. In this article, the term EDTA is used to mean H4-xEDTAx-, whereas in its complexes EDTA4- stands for the tetra-deprotonated ligand.

Coordination chemistry principles

In coordination chemistry, EDTA4- is a member of the polyamino carboxylic acid
Polyamino carboxylic acid
thumb|left|120px|a metal complex with the [[EDTA]] anionthumb|120px|the [[glycine|glycinate]] ion can form a chelate complex with a metal ionthumb|120px| β [[alanine]]...

 family of ligands. EDTA4- usually binds to a metal cation through its two amines and four carboxylates. Many of the resulting coordination compound
Complex (chemistry)
In chemistry, a coordination complex or metal complex, is an atom or ion , bonded to a surrounding array of molecules or anions, that are in turn known as ligands or complexing agents...

s adopt octahedral geometry. Although of little consequence for its applications, these octahedral complexes are chiral
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....

. The anion [Co(EDTA)] has been resolved into enantiomer
Enantiomer
In chemistry, an enantiomer is one of two stereoisomers that are mirror images of each other that are non-superposable , much as one's left and right hands are the same except for opposite orientation. It can be clearly understood if you try to place your hands one over the other without...

s. Many complexes of EDTA4- adopt more complex structures due to (i) the formation of an additional bond to water, i.e. seven-coordinate complexes, or (ii) the displacement of one carboxylate arm by water. Early work on the development of EDTA was undertaken by Gerold Schwarzenbach
Gerold Schwarzenbach
Gerold Karl Schwarzenbach was a Swiss chemist.Schwarzenbach was born and grew up in Horgen, Switzerland. He studied chemistry at the ETH Zurich and graduated in 1928 with his dissertation Studien über die Salzbildung von Beizenfarbstoffen...

 in the 1940s. EDTA forms especially strong complexes with Mn(II), Cu(II), Fe(III), Pb (II) and Co(III).

Several features of EDTA's complexes are relevant to its applications. First, because of its high denticity
Denticity
Denticity refers to the number of atoms in a single ligand that bind to a central atom in a coordination complex. In many cases, only one atom in the ligand binds to the metal, so the denticity equals one, and the ligand is said to be monodentate...

, this ligand has a high affinity for metal cations:
[Fe(H2O)6]3+ + H4EDTA [Fe(EDTA)] + 6 H2O + 4 H+ (Keq = 1025.1)

Written in this way, the equilibrium quotient
Stability constants of complexes
A stability constant is an equilibrium constant for the formation of a complex in solution. It is a measure of the strength of the interaction between the reagents that come together to form the complex...

 shows that metal ions compete with protons for binding to EDTA. Because metal ions are extensively enveloped by EDTA, their catalytic properties
Catalysis
Catalysis is the change in rate of a chemical reaction due to the participation of a substance called a catalyst. Unlike other reagents that participate in the chemical reaction, a catalyst is not consumed by the reaction itself. A catalyst may participate in multiple chemical transformations....

 are often suppressed. Finally, since complexes of EDTA4- are anionic, they tend to be highly soluble in water. For this reason, EDTA is able to dissolve deposits of metal oxides and carbonates.

Industry

In industry, EDTA is mainly used to sequester metal ions in aqueous solution. In the textile industry
Textile
A textile or cloth is a flexible woven material consisting of a network of natural or artificial fibres often referred to as thread or yarn. Yarn is produced by spinning raw fibres of wool, flax, cotton, or other material to produce long strands...

, it prevents metal ion impurities from modifying colours of dyed products. In the pulp and paper industry
Pulp and paper industry
The global pulp and paper industry is dominated by North American , northern European and East Asian countries...

, EDTA inhibits the ability of metal ions, especially Mn2+, from catalyzing the disproportionation
Disproportionation
Disproportionation, also known as dismutation is used to describe a specific type of redox reaction in which a species is simultaneously reduced and oxidized so as to form two different products....

 of hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...

, which is used in "chlorine-free bleaching
Totally chlorine free
Totally chlorine free is a technique that uses no chlorine compounds for the bleaching of wood pulp for paper production. This prevents the formation of dioxins, highly carcinogenic pollutants....

." In a similar manner, EDTA is added to some food as a preservative
Preservative
A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes....

 or stabilizer to prevent catalytic oxidative decoloration, which is catalyzed by metal ions. In personal care products, it is added to cosmetics
Cosmetics
Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...

 to improve their stability toward air. In soft drink
Soft drink
A soft drink is a non-alcoholic beverage that typically contains water , a sweetener, and a flavoring agent...

s containing ascorbic acid
Ascorbic acid
Ascorbic acid is a naturally occurring organic compound with antioxidant properties. It is a white solid, but impure samples can appear yellowish. It dissolves well in water to give mildly acidic solutions. Ascorbic acid is one form of vitamin C. The name is derived from a- and scorbutus , the...

 and sodium benzoate
Sodium benzoate
Sodium benzoate has the chemical formula NaC6H5CO2; it is a widely used food preservative, with E number E211. It is the sodium salt of benzoic acid and exists in this form when dissolved in water. It can be produced by reacting sodium hydroxide with benzoic acid.-Uses:Sodium benzoate is a...

, EDTA mitigates formation of benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

 (a carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...

).

The reduction of water hardness in laundry applications and the dissolution of scale in boilers both rely on EDTA and related complexants
Complex (chemistry)
In chemistry, a coordination complex or metal complex, is an atom or ion , bonded to a surrounding array of molecules or anions, that are in turn known as ligands or complexing agents...

 to bind Ca2+, Mg2+, as well as other metal ions. Once bound to EDTA, these metal centers tend not to form precipitates or to interfere with the action of the soap
Soap
In chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...

s and detergent
Detergent
A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...

s. For similar reasons, cleaning solutions often contain EDTA.

The solubilization of ferric ions near neutral pH is accomplished using EDTA. This property is useful in agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...

 including hydroponics
Hydroponics
Hydroponics is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, or coconut husk.Researchers discovered in the 18th...

, especially in calcareous soils. Otherwise, at near-neutral pH, iron(III) forms insoluble salts, which are less bioavailable. Aqueous [Fe(edta)]- is used for removing ("scrubbing") hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...

 from gas streams. This conversion is achieved by oxidizing the hydrogen sulfur to elemental sulfur, which is non-volatile:
2 [Fe(edta)]- + H2S → 2 [Fe(edta)]2− + S
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

  + 2 H+

In this application, the ferric center is reduced to its ferrous derivative, which can then be reoxidized by air. In similar manner, nitrogen oxide
Nitrogen oxide
Nitrogen oxide can refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:* Nitric oxide, also known as nitrogen monoxide, , nitrogen oxide* Nitrogen dioxide , nitrogen oxide...

s are removed from gas streams using [Fe(edta)]2-. The oxidizing properties of [Fe(edta)]- are also exploited in photography, where it is used to solubilize silver particles.

EDTA was used in the separation of the lanthanide metals by ion-exchange chromatography. Perfected by F.H. Spedding et al. in 1954, the method relies on the steady increase in stability constant of the lanthanide EDTA complexes with atomic number. Using sulfonated polystyrene beads and copper(II) as a retaining ion, EDTA causes the lanthanides to migrate down the column of resin while separating into bands of pure lanthanide. The lanthanides elute in order of decreasing atomic number. Due to the expense of this method, relative to counter-current solvent extraction, ion-exchange is now used only to obtain the highest purities of lanthanide (typically greater than 4N, 99.99%).

Medicine

EDTA is used to bind metal ions in the practice of chelation therapy
Chelation therapy
Chelation therapy is the administration of chelating agents to remove heavy metals from the body. For the most common forms of heavy metal intoxication—those involving lead, arsenic or mercury—the standard of care in the United States dictates the use of dimercaptosuccinic acid...

, e.g., for treating mercury
Mercury poisoning
Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...

 and lead poisoning
Lead poisoning
Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...

. It is used in a similar manner to remove excess iron from the body. This therapy is used to treat the complication of repeated blood transfusions, as would be applied to treat thalassaemia. Alternative medical practitioners believe EDTA acts as a powerful antioxidant
Antioxidant
An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Oxidation is a chemical reaction that transfers electrons or hydrogen from a substance to an oxidizing agent. Oxidation reactions can produce free radicals. In turn, these radicals can start chain reactions. When...

 to prevent free radicals from injuring blood vessel walls, therefore reducing atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...

. The U.S. FDA
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...

 approved the use of EDTA for lead poisoning on July 16, 1953, under the brand name of Versenate, which was licensed to the pharmaceutical company Riker. It has not approved it for the treatment of atherosclerosis.

Dentist
Dentist
A dentist, also known as a 'dental surgeon', is a doctor that specializes in the diagnosis, prevention, and treatment of diseases and conditions of the oral cavity. The dentist's supporting team aides in providing oral health services...

s and endodontists use EDTA solutions to remove inorganic debris (smear layer) and lubricate the canals in endodontics. This procedure helps prepare root canals for obturation. Furthermore, EDTA solutions with the addition of a surfactant loosen up calcifications inside a root canal and allow instrumentation (canals shaping) and facilitate apical advancement of a file in a tight/calcified root canal towards the apex. It serves as a preservative (usually to enhance the action of another preservative such as benzalkonium chloride
Benzalkonium chloride
Benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, is a mixture of alkylbenzyldimethylammonium chlorides of various even-numbered alkyl chain lengths. This product is a nitrogenous cationic surface-acting agent belonging to the quaternary ammonium group...

 or thiomersal
Thiomersal
Thiomersal , and commonly known in the US as thimerosal, is an organomercury compound. This compound is a well established antiseptic and antifungal agent....

) in ocular preparations and eyedrops. In evaluating kidney function, the complex [Cr(edta)]- is administered intravenously and its filtration into the urine is monitored. This method is useful for evaluating glomerular filtration rate.

EDTA is used extensively in the analysis of blood. It is an anticoagulant
Anticoagulant
An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...

 for blood samples for CBC/FBE
Complete blood count
A complete blood count , also known as full blood count or full blood exam or blood panel, is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood...

s.

Laboratory studies also suggest that EDTA chelation may prevent collection of platelets on the lining of the vessel [such as arteries] (which can otherwise lead to formation of blood clots, which itself is associated with atheromatous plaque formation or rupture, and thereby ultimately disrupts blood flow). These ideas have so far been proven ineffective; however, a major clinical study of the effects of EDTA on coronary arteries is currently (2008) proceeding. EDTA played a role in the O.J. Simpson trial when the defense alleged that one of the blood samples collected from Simpson's estate was found to contain traces of the compound.

EDTA is a slime dispersant, and has been found to be highly effective in reducing bacterial growth during implantation of intraocular lenses (IOLs).

Laboratory applications

In the laboratory, EDTA is widely used for scavenging metal ions: In biochemistry
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

 and molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

, ion depletion is commonly used to deactivate metal-dependent enzymes, either as an assay for their reactivity or to suppress damage to DNA or proteins. In analytical chemistry, EDTA is used in complexometric titration
Complexometric titration
Complexometric titration is a form of volumetric analysis in which the formation of a colored complex is used to indicate the end point of a titration. Complexometric titrations are particularly useful for the determination of a mixture of different metal ions in solution...

s and analysis of water hardness or as a masking agent
Masking agent
A masking agent is a reagent used in chemical analysis which reacts with chemical species that may interfere in the analysis.In sports a masking agent is used to hide or prevent detection of a banned substance or illegal drug like anabolic steroids or stimulants...

 to sequester metal ions that would interfere with the analyses.
EDTA finds many specialized uses in the biomedical laboratories, such as in veterinary ophthalmology
Ophthalmology
Ophthalmology is the branch of medicine that deals with the anatomy, physiology and diseases of the eye. An ophthalmologist is a specialist in medical and surgical eye problems...

 as an anticollagenase to prevent the worsening of corneal ulcers in animals. In tissue culture
Tissue culture
Tissue culture is the growth of tissues or cells separate from the organism. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar...

 EDTA is used as a chelating agent that binds to calcium and prevents joining of cadherins between cells, preventing clumping of cells grown in liquid suspension, or detaching adherent cells for passaging. In histopathology, EDTA can be used as a decalcifying agent making it possible to cut sections using a microtome once the tissue sample is demineralised.
EDTA is also known to inhibit a range of metallopeptidases
Metalloproteinase
Metalloproteinases constitute a family of enzymes from the group of proteases, classified by the nature of the most prominent functional group in their active site. These are proteolytic enzymes whose catalytic mechanism involves a metal. Most metalloproteases are zinc-dependent, but some use...

, the method of inhibition occurs via the chelation
Chelation
Chelation is the formation or presence of two or more separate coordinate bonds between apolydentate ligand and a single central atom....

 of the metal ion required for catalytic activity.

Toxicity and environmental considerations

EDTA is in such widespread use that it has emerged as a persistent organic pollutant
Persistent organic pollutant
thumb|right|275px|State parties to the Stockholm Convention on Persistent Organic PollutantsPersistent organic pollutants are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes...

. It degrades to ethylenediaminetriacetic acid, which then cyclizes to the diketopiperizide
Diketopiperazine
Diketopiperazines are a class of cyclic organic compounds that result from peptide bonds between two amino acids to form a lactam. They are the smallest possible cyclic peptides....

, a cumulative, persistent, organic environmental pollutant. An alternative chelating agent with fewer environmental pollution implications is EDDS.

EDTA exhibits low acute toxicity with (rat) of 2.0 – 2.2 g/kg. It has been found to be both cytotoxic
Cytotoxicity
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are a chemical substance, an immune cell or some types of venom .-Cell physiology:...

 and weakly genotoxic in laboratory animals. Oral exposures have been noted to cause reproductive and developmental effects. The same study by Lanigan also found that both dermal exposure to EDTA in most cosmetic formulations and inhalation exposure to EDTA in aerosolized cosmetic formulations would produce exposure levels below those seen to be toxic in oral dosing studies.

Methods of detection and analysis

The most sensitive method of detecting and measuring EDTA in biological samples is selected-reaction-monitoring capillary-electrophoresis
Capillary electrophoresis
Capillary electrophoresis , also known as capillary zone electrophoresis , can be used to separate ionic species by their charge and frictional forces and hydrodynamic radius. In traditional electrophoresis, electrically charged analytes move in a conductive liquid medium under the influence of an...

 mass-spectrometry
Liquid chromatography-mass spectrometry
Liquid chromatography–mass spectrometry is an analytical chemistry technique that combines the physical separation capabilities of liquid chromatography with the mass analysis capabilities of mass spectrometry. LC-MS is a powerful technique used for many applications which has very high...

 (abbreviation SRM-CE/MS) which has a detection limit
Detection limit
In analytical chemistry, the detection limit, lower limit of detection, or LOD , is the lowest quantity of a substance that can be distinguished from the absence of that substance within a stated confidence limit...

 of 7.3 ng/mL in human plasma and a quantitation limit
Detection limit
In analytical chemistry, the detection limit, lower limit of detection, or LOD , is the lowest quantity of a substance that can be distinguished from the absence of that substance within a stated confidence limit...

 of 15 ng/mL. This method works with sample volumes as small as ~7-8 nL.

EDTA has also been measured in non-alcoholic beverages using high performance liquid chromatography
High-performance liquid chromatography
High-performance liquid chromatography , HPLC, is a chromatographic technique that can separate a mixture of compounds and is used in biochemistry and analytical chemistry to identify, quantify and purify the individual components of the mixture.HPLC typically utilizes different types of stationary...

 (HPLC) of 2.0 μg/mL.

External links

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