Copper-EDTA chelate

The first factor can be overcome if the excess of the copper phosphate suspension is centrifuged off, and the copper is converted to a 1 1 copper EDTA chelate with excess of ethylene-diaminetetraacetic acid and determined polarographically.< > In all instances the same complex is reduced, and there is no difference in diffusing particles, and hence in diffusion coefficients. 

Chang, C. and Y. Ku (1997). Adsorption of EDTA-chelated copper ion in aqueous solution by an activated carbon adsorption column, J. Chinese Institute of Engineers, Trans, of the Chinese Institute of Engineers, Series A/Chung-kuo Rung Ch eng Hsuch K an 20, 6, 651-659. 

In contrast to the situation of a decade ago [3.1). a substantial literature has now accumulated on copper removal by activated carbons. This is not only because of metal recovery from acid mine wastes [176] and acidic corrosion of pipes [33] but also because of increasing industrial contamination of water streams [177-182]. In particular.many wastewaters contain complexing ions such as ethylenedi-aminetetraacetate (EDTA) and the removal of EDTA-chelated copper (and other) ions has been a special focus of attention [45,173,183-186]. 

HANDLING CYANIDE The polyvalent ions that might interfere, such as iron and copper, are removed by forming the cyanide complexes, which are more stable than the EDTA chelates. Cyanide is very toxic and should not be handled unless you wear gloves, if you have any cuts or scratches on your hands. Do not place KCN or NaCN in any acid solution because the gas HCN is formed (weak acid being displaced by a strong acid), which is highly toxic. Cyanides in basic solution are safe, if handled properly. Have the TA present when you handle cyanide salts. THE ANTIDOTE IS AMYL NITRITE. 

Masking can be achieved by precipitation, complex formation, oxidation-reduction, and kinetically. A combination of these techniques may be employed. For example, Cu " can be masked by reduction to Cu(I) with ascorbic acid and by complexation with I . Lead can be precipitated with sulfate when bismuth is to be titrated. Most masking is accomplished by selectively forming a stable, soluble complex. Hydroxide ion complexes aluminum ion [Al(OH)4 or AlOa"] so calcium can be titrated. Fluoride masks Sn(IV) in the titration of Sn(II). Ammonia complexes copper so it cannot be titrated with EDTA using murexide indicator. Metals can be titrated in the presence of Cr(III) because its EDTA chelate, although very stable, forms only slowly. 

EDTA (ethylenediaminetetraacetic acid) forms stable metal chelates with a number of metal ions. Using this reagent as a complexing- agent, arsenic, bismuth, and selenium can be determined without any interference in the presence of nickel and cobalt. The cobalt-EDTA chelate is stable in 5 M HCl solution, whereas the corresponding bismuth complex is not. The influence of copper on the determination of arsenic can also be eliminated with EDTA, but not in the determination of selenium. Thiourea has been used to eliminate the influence of copper in the determination of antimony and sodium oxalate to eliminate the influence of copper and nickel in the determination of tin. An addition of thiosemicarbazide and 1,10-phenanthro-line reduces the interference of copper, nickel, platinum, and palladium in the determination of arsenic. 

The activated carbon adsorption of EDTA-chelated copper complexes has also been investigated by several workers as a function of ij was... 

Mayonnaise and salad dressings contain EDTA to reduce the concentrations of certain metal ions. Some plant fertilizers contain EDTA chelates of copper and other metals, providing the metal in a soluble form that plants can utilize. 

The complexers maybe tartrate, ethylenediaminetetraacetic acid (EDTA), tetrakis(2-hydroxypropyl)ethylenediamine, nittilotriacetic acid (NTA), or some other strong chelate. Numerous proprietary stabilizers, eg, sulfur compounds, nitrogen heterocycles, and cyanides (qv) are used (2,44). These formulated baths differ ia deposition rate, ease of waste treatment, stabiHty, bath life, copper color and ductiHty, operating temperature, and component concentration. Most have been developed for specific processes all deposit nearly pure copper metal. 

A copper chelate selectively protects the q -NH2 group in lysine. The chelate is cleaved by 2 A HCl or by EDTA (H02CCH2)2NCH2CH2N(CH2C02H)2. ... 

Phosphonates exhibit all the properties of polyphosphates, such as threshold effect, crystal distortion, and sequestration, but are superior in their effectiveness. They provide good chelates for calcium, magnesium, iron, and copper and are commonly used where iron fouling is a problem. Their sequestering properties are generally superior to other common chelants, such as EDTA and NTA. 

The rate of peroxide decomposition and the resultant rate of oxidation are markedly increased by the presence of ions of metals such as iron, copper, manganese, and cobalt [13]. This catalytic decomposition is based on a redox mechanism, as in Figure 15.2. Consequently, it is important to control and limit the amounts of metal impurities in raw rubber. The influence of antioxidants against these rubber poisons depends at least partially on a complex formation (chelation) of the damaging ion. In favor of this theory is the fact that simple chelating agents that have no aging-protective activity, like ethylene diamine tetracetic acid (EDTA), act as copper protectors. 

Koehler, F.M., Rossier, M., Waelle, M., Athanassiou, E.K., Limbach, L.K., Grass, R.N., Gunther, D. and Stark, W.J. (2009) Magnetic EDTA coupling heavy metal chelators to metal nanomagnets for rapid removal of cadmium, lead and copper from contaminated water. Chemical Communications, (32), 4862—4864. 

The heavy metals copper, manganese, cobalt and zinc were omitted individually and in combination from MS and B5 media to determine the effect on antibody stability in solution [63]. When IgG, antibody was added to these modified media in experiments similar to the one represented in Figure 2.2, only the B5 medium without Mn showed a significant improvement in antibody retention relative to normal culture media. Nevertheless, protein losses were considerable as only about 30% of the added antibody could be detected in the Mn-free medium after about 5 h. The beneficial effect of removing Mn was lost when all four heavy metals, Cu, Mn, Co and Zn, were omitted simultaneously. The reason for these results is unclear. Addition of the metal chelating agent ethylenediaminetetraacetate (EDTA) had a negligible effect on antibody retention in both MS and B5 media [63]. 

When the chelators are actually known, as in the case of industrial materials injected into the environment, it is possible to derive much more information from the analyses. Thus high pressure liquid chromatography has been used to separate the copper chelates of EDTA, NTA, EGTA, and CDTA with the final measurement of copper being made by atomic absorption [422,423]. 

Treatment. Since the 1950s, the treatment of Wilson s disease has relied on chelating agents [25]. Early attempts to use BAL or EDTA for this purpose were unsuccessful, but penicillamine, triethylene tetramine dihydrochloride (trientine), and tetrathiomolybdate, all in combination with a low-copper diet, have proved to be effective, and result in the urinary excretion of large amounts of copper. The use of penicillamine is complicated by the fact that it may induce a transient worsening of neurologic function due to rapid mobilization of copper, and also has other side-effects, such as the development of nephrosis. Tetrathiomolybdate is an effective alternative with fewer side-effects [26]. In cases in which the dose was rapidly escalated, however, bone marrow suppression or liver function abnormalities have been described. 

This method should be preferred if protein concentration has to be determined in the presence of detergents. But if copper chelators, such as EDTA, or reductants, such as 2-mercaproethanol or DTE/DTT or reducing carbohydrates (e.g. > 10 mM glucose), are components of the sample, the test does not work reliably. 

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