chelating agents


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Related to chelating agents: EDTA, chelate compound

chelating agents

(kē`lātĭng). Certain organic compounds are capable of forming coordinate bonds (see chemical bondchemical bond,
mechanism whereby atoms combine to form molecules. There is a chemical bond between two atoms or groups of atoms when the forces acting between them are strong enough to lead to the formation of an aggregate with sufficient stability to be regarded as an
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) with metals through two or more atoms of the organic compound; such organic compounds are called chelating agents. The compound formed by a chelating agent and a metal is called a chelate. A chelating agent that has two coordinating atoms is called bidentate; one that has three, tridentate; and so on. EDTA, or ethylenediaminetetraacetate, (O2CH2)2NCH2CH2N(CH2CO2)2, is a common hexadentate chelating agent. Chlorophyll is a chelate that consists of a magnesium ion joined with a complex chelating agent; heme, part of the hemoglobin in blood, is an iron chelate. Chelating agents are important in textile dyeing, water softening, and enzyme deactivation and as bacteriocides.
References in periodicals archive ?
The contrast agent's molecular structure determines its stability and if it can be re-chelated by a given chelating agent. The molecular formula of GdDTPA and ZnDTPA are similar, as is the Log K (thermodynamic stability constant).
The work reported in this article has demonstrated the feasibility of the adapted chemical transformation to graft silica surface with PAR chelating agent and similar moieties.
* Sun Care--solubilizers, dispersing agents, emollients and chelating agents
Two-Way ANOVA test showed that while the different chelating agents significantly affected the push-out bonding strength of the root canal filling (p<0.05), the different SAF working times did not (p>0.05) (Table 1).
Temperature Ramp time Hold time Steps ([degrees]) (s) (s) Drying 120 10 15 Pyrolysis 600 5 20 Atomization 2000 0 5 Cleaning 2400 1 3 Argon flow rate Steps (mL x [min.sup.-1]) Drying 250 Pyrolysis 250 Atomization 0 Cleaning 250 Table 2: The atomic absorbance of three chelating agents in three different extraction solvents.
Sample treatments to achieve this could include adjusting the pH to influence hydrogen bonding or adding Mg2+/Ca2+ ions to the solution to saturate the chelating agent and prevent destabilization of the LPS aggregates.
Oral chelating agents are best given on an empty stomach.
Dimercaprol and DMPS are chelating agents principally involved in the treatment of poisoning by arsenic and polonium-210, respectively.
"The expanded capacities for chelating agents at our Ludwigshafen site enable us to respond to the increasing demand in Europe."
Chelate forms of adsorbents were synthesized in three stages: first stage synthesis of [[Zn.sub.4][Al.sub.2][(OH).sub.12]]*C[O.sub.3]*n[H.sub.2]O (Zn,Al-C[O.sub.3]), second obtaining [Zn.sub.4][Al.sub.2][O.sub.7] of synthesized Zn,Al-C[O.sub.3] via its heat treatment at 450[degrees]C for 1 to 2h, and the third stage synthesis of chelate forms of Zn,Al-L via interaction of mixed oxide [Zn.sub.4][Al.sub.2][O.sub.7] with aqueous solutions of certain chelating agents containing ammonium hydroxide.
Horticultural Research Laboratory in Fort Pierce, Florida, has found a promising alternative to these chelating agents. In several greenhouse studies, Albano used EDDS--a readily biodegradable chelating agent--and observed that there was no significant difference in the health, growth patterns, or micronutrient levels in marigolds grown with EDDS and marigolds grown with other popular iron chelating agents.
The company said that the proprietary next generation formula does not contain Ethylene diamine tetracetic acid (EDTA) or any other stabilisation and chelating agents and is free of preservatives.