Ethylenediaminetetra acetic acid

Multidentate ligands contain more than two coordinating atoms per molecule, e.g. 1,2-diaminoethanetetra-acetic acid (ethylenediaminetetra-acetic acid, EDTA),f which has two donor nitrogen atoms and four donor oxygen atoms in the molecule, can be hexadentate. 

The formation of a single complex species rather than the stepwise production of such species will clearly simplify complexometric titrations and facilitate the detection of end points. Schwarzenbach2 realised that the acetate ion is able to form acetato complexes of low stability with nearly all polyvalent cations, and that if this property could be reinforced by the chelate effect, then much stronger complexes would be formed by most metal cations. He found that the aminopolycarboxylic acids are excellent complexing agents the most important of these is 1,2-diaminoethanetetra-aceticacid (ethylenediaminetetra-acetic acid). The formula (I) is preferred to (II), since it has been shown from measurements of the dissociation constants that two hydrogen atoms are probably held in the form of zwitterions. The values of pK are respectively pK, = 2.0, pK2 = 2.7,... 

Crucibles fitted with permanent porous plates are cleaned by shaking out as much of the solid as possible, and then dissolving out the remainder of the solid with a suitable solvent. A hot 0.1 M solution of the tetrasodium salt of the ethylenediaminetetra-acetic acid is an excellent solvent for many of the precipitates [except metallic sulphides and hexacyanoferrates(III)] encountered in analysis. These include barium sulphate, calcium oxalate, calcium phosphate, calcium oxide, lead carbonate, lead iodate, lead oxalate, and ammonium magnesium phosphate. The crucible may either be completely immersed in the hot reagent or the latter may be drawn by suction through the crucible. 

Ethylenediaminetetra-acetic acid, largely as the disodium salt of EDTA, is a very important reagent for complex formation titrations and has become one of the most important reagents used in titrimetric analysis. Equivalence point detection by the use of metal-ion indicators has greatly enhanced its value in titrimetry. 

Ethylenediaminetetra-acetic acid (disodium salt see EDTA... 

Ru(bipy)3 formed in this reaction is reduced by the sacrificial electron donor sodium ethylenediaminetetra-acetic acid, EDTA. Cat is the colloidal catalyst. With platinum, the quantum yield of hydrogenation was 9.9 x 10 . The yield for C H hydrogenation was much lower. However, it could substantially be improv l by using a Pt colloid which was covered by palladium This example demonstrates that complex colloidal metal catalysts may have specific actions. Bimetalic alloys of high specific area often can prepared by radiolytic reduction of metal ions 3.44) Reactions of oxidizing radicals with colloidal metals have been investigated less thoroughly. OH radicals react with colloidal platinum to form a thin oxide layer which increases the optical absorbance in the UV and protects the colloid from further radical attack. Complexed halide atoms, such as Cl , Br, and I, also react... 

High-performance liquid chromatography (HPLC) with a micellar mobile phase or with a selective pre-column or reaction detection system has also been used to determine alkylenebis(dithiocarbamaes). ° Zineb and mancozeb residues in feed were determined by ion-pair HPLC with ultraviolet (UV) detection at 272 nm. These compounds were converted to water-soluble sodium salts with ethylenediaminetetra-acetic acid (EDTA) and sodium hydroxide. The extracts were ion-pair methylated with tetrabuthylammonium hydrogensulfate (ion-pair reagent) in a chloroform-hexane solvent mixture at pH 6.5-8.S. The use of an electrochemical detector has also been reported. ... 

Similar experiments were performed to measure the ET rate constants for the reaction between ZnPor in benzonitrile and aqueous reductants, Ru(CN)g, Mo(CN)g and FeEDTA (where EDTA denotes ethylenediaminetetra-acetic acid). Although the... 

The standard procedure for removal of active-site vanadium(V) has been to incubate V-BrPO in 0.1 Mphosphate-citrate buffer pH 3.8, containing 10 mM ethylenediaminetetra-acetic acid (edta). These conditions remove over 95% of the vanadium, which produces the inactive apo-BrPO derivative [1,45]. The essential component of the apoprotein preparation is the phosphate, without which vanadium is not completely removed and the enzyme is not completely inactivated [46], In fact phosphate in the absence of edta is sufficient for preparation of apo-BrPO [46] inactivation by phosphate is much faster at low pH (pH 4) than at neutral or higher pH. However, phosphate inactivation does not occur in the presence of dihydrogen peroxide [46],... 

Alkylphosphonate groups are monodentate donors of intermediate hardness that may replace carboxylate groups in chelating agents such as nitrilotriacetic acid (NTA), ethylenediaminetetra-acetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA). The corresponding ligands nitrilotrimethylenephosphonic acid (NTP), 1, ethylenediaminetetramethylenephosphonic acid (EDTP),... 

TE buffer 10 mM Tris-HCl, pH 8, 1 mM ethylenediaminetetra-acetic acid disodium salt (NajEDTA) autoclave. 

Multidentate Ugand - these have several points of attachment, e.g. ethylenediaminetetra-acetic acid (EDTA), which is a hexadentate ligand (six points of attachment) (Fig. 23.2). 

In polybasic acids, the effect of chelation appears between later /C s. For example, in ethylenediaminetetra-acetic acid the first two hydrogen ions can dissociate readily, but the third and later ionizations axe greatly hindered by H bonding. 

The proteins of the cell envelope of Ps. aeruginosa have received somewhat less attention than the other components. Recently, it was found [17] that the envelope contains a wide variety of proteins. There do, however, appear to be three characteristic proteins, two of which are gylcoproteins and are found associated with the protein-lipopolysaccharide complex released on treatment of envelopes with ethylenediaminetetra-acetic acid (EDTA). This complex is part of the outer layer of the envelope [18]. 

Elm Ethylenediaminetetra-acetic acid Eetal alcohol syndrome... 

Sodium calciumedetate is the calcium chelate of the disodium salt of ethylenediaminetetra-acetic acid (calcium EDTA). It is effective in acute lead poisoning because of its capacity to exchange calcium for lead the lead chelate is excreted in the urine, leaving behind a harmless amount of calcium. Dimercaprol may usefully be combined with sodium calciumedetate when lead poisoning is severe, e.g. with encephalopathy. 

The complexing ability of ethylenediaminetetra-acetic acid (EDTA, H4Y) has been exploited in the coulometric titration of metal ions. The method depends on the reduction of the mercury(II) or cadmium chelate of EDTA and on the titration of the metal ion (for example, magnesium) to be determined by the anion of EDTA that is released. 

Cholecystitis can be induced, at least when methyl-tert-butylether is used alongside ethylenediaminetetra-acetic acid (SEDA-16, 428). Most such effects are probably attributable to over-rapid infusion. 

Soon after the introduction of propofol in 1989, clusters of infections related to its use were reported, and there have since been several reports (77,78). The complications include hypotension, tachycardia, septic shock, convulsions, and death. Ethylenediaminetetra-acetic acid (EDTA) was added to the formulation to retard microbial growth. However, there have been concerns over the effects of this additive on trace element homeostasis, particularly when it is used in intensive care units for long-term sedation. Five randomized controlled trials have been reviewed, and minimal or no effects have been found on zinc, magnesium, or calcium homeostasis. However, there is no evidence to suggest that cluster infection has been or will be reduced with this formulation and there is still a need for care with sterility when using this product. 

Improvements in modes of complexing by Marsh (1950), who separated lanthanides by fractional crystallisation of the ethylenediaminetetra-acetic acid (EDTA) complexes, have been coupled with the ion exchange technique by Vickery (1952). EDTA proved an even more satisfactory complexing agent than citric acid and gave purer specimens than any other method. 

Schwarzenbach (1945) has developed the use of such chelating agents as nitrilotriacetic acid (a), ethylenediaminetetra-acetic acid (b) and 1 2 diaminocyclohexanetetra-acetic acid (c). 

This reaction is particularly catalyzed by copper. A large excess of ammonia and the addition of complexing agents such as ethylenediaminetetra-acetic acid (EDTA) are used as countermeasures. 

Trypsin ethylenediaminetetra-acetic acid (EDTA) (Gibco-BRL Life Technologies, Gaithersburg, MD). 

Fig. 2 Chelation between a metal ion (M+) and ethylenediaminetetra-acetic acid (EDTA), a well-known laboratory ligand. Note that the six coordination bonds (white) are made between dissociated -0 groups and lone pairs of electrons (denoted by double dots) on the N atoms of the EDTA. Similar coordination bonds are made in fulvic acid chelates.

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