Highly sensitive colour change system within slight differences in metal ion concentrations based on homo–binuclear complex formation equilibrium for visual threshold detection of trace metal ions

2004 ◽  
Vol 527 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Hitoshi Mizuguchi ◽  
Hiroshi Atsumi ◽  
Keigo Hashimoto ◽  
Yasuhiro Shimada ◽  
Yuki Kudo ◽  
...  
Keyword(s):  
Complex Formation ◽  
Binuclear Complex ◽  
Metal Ion ◽  
Colour Change ◽  
Threshold Detection ◽  
Trace Metal Ions ◽  
Ion Concentrations ◽  
Visual Threshold ◽  
Highly Sensitive ◽  
Change System

Visual Threshold Detection of Iron(III) at ppb Level Based on Homo-binuclear Complex Formation System Equipped with Ion-exchanger Colorimetry

2014 ◽  
Vol 63 (6) ◽  
pp. 515-523 ◽  
Author(s):  
Hitoshi MIZUGUCHI ◽  
Yasuko SHINODA ◽  
Takayoshi WAGATSUMA ◽  
Masayuki TAKADA ◽  
Toshio KAMIJO ◽  
...  
Keyword(s):  
Complex Formation ◽  
Binuclear Complex ◽  
Ion Exchanger ◽  
Threshold Detection ◽  
Visual Threshold ◽  
Formation System

Prediction of Soluble Nickel Removal by Activated Sludge Using Free Metal Ion Concentrations

1987 ◽  
Vol 19 (3-4) ◽  
pp. 439-448 ◽  
Author(s):  
Jeppe S. Nielsen ◽  
Steve E. Hrudey ◽  
Frederick F. Cantwell
Keyword(s):  
Activated Sludge ◽  
Metal Ion ◽  
Municipal Sewage ◽  
Nickel Ion ◽  
Ion Concentrations ◽  
Untreated Sewage ◽  
Nickel Uptake ◽  
Nickel Removal ◽  
Free Metal ◽  
Free Metal Ion

Batch isotherm studies using spiked sewage samples containing a range of total soluble nickel concentrations typical of municipal sewage strongly suggested that it is the free (i.e. uncomplexed) nickel ion that is sorbed by activated sludge. Equations relating nickel uptake by activated sludge to free nickel ion concentrations and the extent of complexation in untreated sewage were developed and applied. Predicted and measured nickel removals generally agreed to within ± 30%.

Ternary complexes of N-carboxymethylaminoacetohydroxamic acid

1981 ◽  
Vol 46 (5) ◽  
pp. 1107-1115 ◽  
Author(s):  
Rolf Karlíček ◽  
Miroslav Polášek ◽  
Vladimír Jokl
Keyword(s):  
Complex Formation ◽  
Ternary System ◽  
Binuclear Complex ◽  
Functional Group ◽  
Hydroxamic Acids ◽  
Ternary Complexes ◽  
Hydrogen Ions ◽  
Ligand Structure ◽  
Excess Copper

The formation of N-carboxymethylaminoacetohydroxamic acid complexes in solutions with excess copper(II) or iron(III) ions or both of them was studied. In the presence of Cu(II), the binuclear complex Cu2H-1L+ was identified; in the ternary system, the complex CuFeH-1L+ was found. This complex formation is necessarily associated with the ligand structure >N-CH2.CO-NHOH and with a new property of hydroxamic acids of this type - detachment of two hydrogen ions from one carbohydroxamic functional group.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

scholarly journals Uncommon biphasic behaviour induced by very high metal ion concentrations in HCl/H2O/[P44414]Cl and HCl/H2O/PEG-600 systems

2020 ◽  
Vol 22 (40) ◽  
pp. 23226-23236
Author(s):  
Eris Sinoimeri ◽  
Victor Maia Fernandes ◽  
Jérôme Cognard ◽  
Jorge Fernando Brandão Pereira ◽  
Lenka Svecova ◽  
...  
Keyword(s):  
Metal Ion ◽  
Ion Concentrations ◽  
System P ◽  
High Metal ◽  
Very High ◽  
Peg 600

Large amounts of Fe(iii) or Fe(ii) strongly modify the biphasic behavior of the system P44414Cl/HCl/H2O while large amounts of Fe(iii) induce a biphasic regime for the mixture PEG-600/HCl/H2O.

scholarly journals Hypochlorite and superoxide radicals can act synergistically to induce fragmentation of hyaluronan and chondroitin sulphates

2004 ◽  
Vol 381 (1) ◽  
pp. 175-184 ◽  
Author(s):  
Martin D. REES ◽  
Clare L. HAWKINS ◽  
Michael J. DAVIES
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Chloride Ions ◽  
Superoxide Radicals ◽  
Thermal Source ◽  
Site Specific ◽  
Trace Metal Ions ◽  
Electron Reduction ◽  
Polymer Fragmentation

Activated phagocytes release the haem enzyme MPO (myeloperoxidase) and also generate superoxide radicals (O2•−), and hence H2O2, via an oxidative burst. Reaction of MPO with H2O2 in the presence of chloride ions generates HOCl (the physiological mixture of hypochlorous acid and its anion present at pH 7.4). Exposure of glycosaminoglycans to a MPO–H2O2–Cl− system or reagent HOCl generates long-lived chloramides [R-NCl-C(O)-R′] derived from the glycosamine N-acetyl functions. Decomposition of these species by transition metal ions gives polymer-derived amidyl (nitrogen-centred) radicals [R-N•-C(O)-R′], polymer-derived carbon-centred radicals and site-specific strand scission. In the present study, we have shown that exposure of glycosaminoglycan chloramides to O2•− also promotes chloramide decomposition and glycosaminoglycan fragmentation. These processes are inhibited by superoxide dismutase, metal ion chelators and the metal ion-binding protein BSA, consistent with chloramide decomposition and polymer fragmentation occurring via O2•−-dependent one-electron reduction, possibly catalysed by trace metal ions. Polymer fragmentation induced by O2•− [generated by the superoxide thermal source 1, di-(4-carboxybenzyl)hyponitrite] was demonstrated to be entirely chloramide dependent as no fragmentation occurred with the native polymers or when the chloramides were quenched by prior treatment with methionine. EPR spin-trapping experiments using 5,5-dimethyl1-pyrroline-N-oxide and 2-methyl-2-nitrosopropane have provided evidence for both O2•− and polymer-derived carbon-centred radicals as intermediates. The results obtained are consistent with a mechanism involving one-electron reduction of the chloramides to yield polymer-derived amidyl radicals, which subsequently undergo intramolecular hydrogen atom abstraction reactions to give carbon-centred radicals. The latter undergo fragmentation reactions in a site-specific manner. This synergistic damage to glycosaminoglycans induced by HOCl and O2•− may be of significance at sites of inflammation where both oxidants are generated concurrently.

Lab in a tube: a fast-assembled colorimetric sensor for highly sensitive detection of oligonucleotides based on a hybridization chain reaction

RSC Advances ◽  
2015 ◽  
Vol 5 (55) ◽  
pp. 44714-44721 ◽  
Author(s):  
Siqi Zhang ◽  
Kun Wang ◽  
Zhenyu Li ◽  
Zhongmin Feng ◽  
Ting Sun
Keyword(s):  
Complex Formation ◽  
Dna Sequence ◽  
Self Assembly ◽  
The Self ◽  
Hybridization Chain Reaction ◽  
Chain Reaction ◽  
Highly Sensitive ◽  
G Quadruplex ◽  
Colored Product ◽  
Highly Sensitive Detection

Upon adding THBV, the self-assembly of THBV with H1 allows the rest of the DNA sequence of H1 to accelerate H1–H2 complex formation. The G-quadruplex at the end of the H1–H2 complex could catalyze TMB into a colored product.

scholarly journals Pre-treatment of desalination feed seawater by Jordanian Tripoli, Pozzolana, and Feldspar: Batch experiments

2011 ◽  
Vol 17 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Aiman Al-Rawajfeh ◽  
Khaldoon Al-Whoosh ◽  
Dwairi Al ◽  
Ahmad Al-Maaberah ◽  
Amer Tarawneh
Keyword(s):  
Layered Double Hydroxide ◽  
Metal Ion ◽  
Raw Materials ◽  
Batch Experiments ◽  
Initial Concentration ◽  
Considerable Potential ◽  
Ion Concentrations ◽  
Pre Treatment ◽  
Co Precipitation ◽  
Double Hydroxide

In this research, composites of layered double hydroxide (LDH) with three Jordanian natural raw materials; Tripoli (T), Pozzolana (P) and Feldspar (F) were prepared by co-precipitation and have been used for feed seawater pre-treatment. The data reveals that percent adsorption decreased with increase in initial concentration, but the actual amount of adsorbed ions per unit mass of LDH/T-P-F increased with increase in metal ion concentrations. The values of ?Go were negative and within 21 to 26 KJ/mol, while the values of ?Ho and ?So were positive and within the range of 0.1 to 25 KJ/mol. The values of ?H?, ?S?, and ?G? indicate the favorability of physisorption and show that the LDH/T-P-F composites have a considerable potential as adsorbents for the removal of ions from seawater.

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