Citric acid iron complex

Ferric casse is also affected by pH. Indeed, iron has a degree of oxidation of three and prodnces soluble complexes with molecules such as citric acid. These complexes are destabilized by increasing pH to prodnce insolnble salts, snch as ferric phosphates (see white casse ) or even ferric hydroxide, Fe(OH)3. 

Several additional formulations with EDTA (or citric acid) and other materials have been proposed. Martin patented a mixture of hydrogen peroxide, oxalic acid, and an EDTA or citric acid-type complexer for removing copper deposits (iron oxides are removed by using an additional stage). An unusual aspect of this process is that it is performed at a pH of 3.0-6.0. To allow passivation of the steel to be effective, oxidative copper-removal processes usually are conducted at pH values of >9.0. 

Chelants at concentrations of 0.1 to 0.2% improve the oxidative stabiUty through the complexation of the trace metal ions, eg, iron, which cataly2e the oxidative processes. Examples of the chelants commonly used are pentasodium diethylenetriarninepentaacetic acid (DTPA), tetrasodium ethylenediarninetetraacetic acid (EDTA), sodium etidronate (EHDP), and citric acid. Magnesium siUcate, formed in wet soap through the reaction of magnesium and siUcate ions, is another chelant commonly used in simple soap bars. 

Manufacture of vitamin C starts with the conversion of sorbitol to L-sorbose. Sorbitol and xyHtol have been used for parenteral nutrition following severe injury, bums, or surgery (246). An iron—sorbitol—citric acid complex is an intramuscular bematinic (247). Mannitol administered intravenously (248) and isosorbide administered orally (249) are osmotic diuretics. Mannitol hexanitrate and isosorbide dinitrate are antianginal dmgs (see Cardiovascular agents). 

Ascorbic acid also forms soluble chelate complexes with iron (142—145). It seems ascorbic acid has no effect on high iron levels found in people with iron overload (146). It is well known, in fact, that ascorbic acid in the presence of iron can exhibit either prooxidant or antioxidant effects, depending on the concentration used (147). The combination of citric acid and ascorbic acid may enhance the iron load in aging populations. Iron overload may be the most important common etiologic factor in the development of heart disease, cancer, diabetes, osteoporosis, arthritis, and possibly other disorders. The synergistic combination of citric acid and ascorbic acid needs further study, particularly because the iron overload produced may be correctable (147). 

When induced in macrophages, iNOS produces large amounts of NO which represents a major cytotoxic principle of those cells. Due to its affinity to protein-bound iron, NO can inhibit a number of key enzymes that contain iron in their catalytic centers. These include ribonucleotide reductase (rate-limiting in DNA replication), iron-sulfur cluster-dependent enzymes (complex I and II) involved in mitochondrial electron transport and cis-aconitase in the citric acid cycle. In addition, higher concentrations of NO,... 

Iron can be controlled with certain complexing agents, in particular glucono-5-lactone, citric acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, hydroxyethylethylene diaminetriacetic acid, hydroxyethyliminodiacetic acid, and the salts from the aforementioned compounds. These compounds must be added together with nitrogen-containing compounds such as hydroxylamine salts or hydrazine salts [486,643,1815]. 

In [20], the composition of the citrate precursor of CoFe204 is proposed as Co3Fe604(C6H607)8-6H20, i.e., two protons are detached from each molecule of citric acid, and the complex compound could be classified as an acidic salt. Distinct signatures of complex formation are obtained by means of infrared (IR) spectroscopy and nuclear magnetic resonance (NMR) for citrate complexes of iron and yttrium, potential precursors of YFe04 and... 

Todorovsky, D. S., Dumanova, D. G., Todorovska, R. V., Getsova, M. M., Preparation and characterization of yttrium-iron citric acid complexes, Croat. Chem. Acta 75, 155-164(2002). 

In the EPR of mammalian cells, we do not see much in addition to the signals from the respiratory complexes. The enzyme aconitase from the citric-acid cycle can be detected, and also the protein cytoplasmic aconitase, later identified as the mRNA translation regulatory factor iron regulatory protein IRP-1, which actually started its career in biochemistry as an EPR signal that could not be assigned to the respiratory chain (Kennedy et al. 1992). 

The percentage collection of chromium (III) with hydrated iron (III) oxide may decrease considerably in the neutral pH range when organic materials capable of combining with chromium (III), such as citric acid and certain amino acids, are added to the seawater [41]. Moreover, synthesised organic chromium (III) complexes are scarcely collected with hydrated iron (III) oxide over a wide pH range [41]. 

The iron absorption is enhanced when soluble monomeric complexes are formed (in the presence of e.g. proteins, aminoacids, ascorbic acid, EDTA, citric acid etc.) [13]. 

Similar photo-induced reductive dissolution to that reported for lepidocrocite in the presence of citric acid has been observed for hematite (a-Fe203) in the presence of S(IV) oxyanions (42) (see Figure 3). As shown in the conceptual model of Faust and Hoffmann (42) in Figure 4, two major pathways may lead to the production of Fe(II)ag i) surface redox reactions, both photochemical and thermal (dark), involving Fe(III)-S(IV) surface complexes (reactions 3 and 4 in Figure 4), and ii) aqueous phase photochemical and thermal redox reactions (reactions 11 and 12 in Figure 4). However, the rate of hematite dissolution (reaction 5) limits the rate at which Fe(II)aq may be produced by aqueous phase pathways (reactions 11 and 12) by limiting the availability of Fe(III)aq for such reactions. The rate of total aqueous iron production (d[Fe(aq)]T/dt = d [Fe(III)aq] +... 

Hydroxamates have been observed in the water in the Bay of Quinte, a eutrophic bay of Lake Ontario, and are believed to be produced by blue-green algae (76). Simpson and Neilands (77) have identified schizokinen, a hydroxamic acid derivative of citric acid as an extracellular product of the blue-green algae, Anabaena sp. However, not all Anabaena produce hydroxamates, Walsby (78) has shown that Anabaena cylindrica releases a large pigmented, peptide-containing material which complexes iron. As yet these peptides have not been examined for ability to complex the actinides. 

In irradiated potatoes, especially in some varieties and as a function of cultivating conditions of the raw material, after-cooking darkening may occur. This discoloration is attributed to formation of ferric-phenolic complexes. This phenomenon depends on the iron content, and is related to increased polyphenol formation and reduced citric acid levels, which are influenced by agronomic and climatic factors. Various technological measures have been developed to prevent this after-cooking darkening [23]. 

Lindvall and Anderson (90) prepared an ill-defined complex by adding an aqueous solution of ferric chloride in small increments to a solution containing sorbitol, citric acid, and the dextran held at 60°. The pH of the solution was adjusted to approximately 7.5 after the addition of each aliquot of the iron. The resulting iron complex can be precipitated with... 

Iron trivalent, parenteral preparations iron-sorbitol-citric acid complex... 

Parenteral preparations Iron dextran (IMFERON) Iron-sorbitol citric acid complex (JECTOFER). 

Iron sorbitol-citric acid complex Isatidine... 

Iron and copper in wines may form complexes with other components to produce deposits or clouds in white wines. Iron clouds generally occur at a pH range from 2.9 to 3.6 and are often controlled by adding citric acid to the wines (2). Copper clouds appear in wines when high levels of copper and sulfur dioxide exist and are a combination of sediments, protein-tannin, copper-protein, and copper-sulfur complexes (169). Further, the browning rate of white wines increases in the presence of copper and iron (143). The results of this study indicate that iron increased the browning rate more than copper. 

Citric acid forms a mixed-metal complex with iron and uranium, similar to the U-citrate complex the Fe-U citrate complex is inert to biodegradation [333a]. A series of publications are dedicated to uranium peroxo complexes with various coligands tri- and quadridentate Schiff bases [334,335], amines, or amino-... 

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