Magnesium ethylenediaminetetraacetate

Disodium magnesium ethylenediaminetetraacetate [14402-88-1] M 358.5. Dissolved in a small amount of water, filtered and ppted with an excess of methanol. Dried at 80 . 

Calcium and magnesium can be titrated readily with disodium ethylenediaminetetraacetate, with Eriochrome Black T as the indicator. The solution is buffered at pH 10.0. Certain metal ions interfere with this procedure by causing fading or indistinct end points. Cyanide, sulfide, or hydroxjiamine can be used to eliminate or minimise the interferences. 

A very important ligand (or chelating agent) for titrimetric analysis is the ethylenediaminetetraacetate (EDTA) ligand. It is especially useful in reacting with calcium and magnesium ions in hard water such that water hardness can be determined. The next section is devoted to this subject. 

List of Abbreviations cDNA, complementary DNA ddH20, double-distilled H2O dNTP, deoxyribonu-cleotide triphosphate EDTA, ethylenediaminetetraacetic acid MgCl2, magnesium chloride mRNA, messenger ribonucleic acid NaOH, sodium hydroxide PCR, polymerase chain reaction qRT PCR, quantitative reverse transcriptase polymerase chain reaction RNase, ribonuclease RT PCR, reverse transcriptase polymerase chain reaction UTR, untranslated region... 

Radium in hydrochloric acid solution may be separated effectively by ion exchange methods using cation exchange-resin columns. A weak HCl solution is passed through the column. The absorbed metals on the ion-exchange column are eluted with ethylenediaminetetraacetic acid (EDTA) at pH 6.25 or with ammonium citrate at pH 7.8. With either eluant, radium is eluted last, after removing barium and then lanthanum, calcium, magnesium, and other metals. 

The luciferase activity was measured using a luminometer equipped with two dispensers. The microtiter plates were thawed and shaken for 2 min at room temperature and placed in the luminometer. One hundred mieroliters of glow mix (20 mM tryein, 1.07 mM magnesium hydroxide carbonate pentahydrate, 2.67 mM magnesium sulfate, 0.1 mM ethylenediaminetetraacetic acid, 33.3 mM dithiothreitol, 270 pM eoenzyme A, 470 pM lueiferin) were automatically injected into each well. The light output was reeorded on whieh the reaetion was stopped by automatic injection of 100 pi of 0.2-M NaOH. 

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

Magnesium ions are essential for superprecipitation. This is borne out by the fact that an excess of EDTA (ethylenediaminetetraacetic acid) leads to complete inhibition. Another powerful inhibitor of superprecipitation is the sodium salt of o-[(3-hydroxymercuri-2-methoxypropyl)car-bamoyl]phenoxyacetic acid ( Salyrgan ). 

Years ago, the indicator used for the titration of calcium and magnesium was a soap solution. As long as calcium and magnesium were present, no soap suds would form. The solution was shaken continuously as the titrant was added, and the first appearance of soap suds was the endpoint. This was a difficult endpoint to reproduce. The discovery by Swartzenback that ethylenediaminetetraacetic acid (EOTA) would chelate with calcium and magnesium ended the soap... 

Edetate disodium, a heavy metal antagonist, is indicated in hypercalcemia (500 mg/kg daily by slow IV infusion) and in digitalis-induced cardiac arrhythmias (15 mg/kg/hour by IV infusion). Ethylenediaminetetraacetic acid (EDTA) will lower serum levels of calcium, magnesium, and zinc. It should not be used in anuria, and renal excretory functions (BUN and creatinine) should be monitored carefully. EDTA should be used cautiously in hypokalemia and in patients with limited cardiac reserve. 

EDTA Ethylenediaminetetraacetic acid, (HOOCCH2)2N(CH2)2N(CH2COOH)2 A compound that acts as a chelating agent, reversibly binding with iron, magnesium, and other metal ions. It is used in certain culture media bound with iron, which it slowiy releases into the medium, and also in some forms of quantitative analysis. 

Two chelating agents, ethylenediaminetetraacetic acid (EDTA) and 8-hydroxyquinoline, also have been used for calcium and magnesium determinations. They are effective in controlling a number of interfering ions, including phosphate, sulfate, aluminum, silicon, boron, and selenium. 

Water hardness is the total calcium and magnesium ion concentration in a water sample and is expressed as the concentration of calcium carbonate. Temporary hardness is that part of the total hardness that disappears on boiling. Whilst not being accepted as a standard method, the use of ion-selective electrodes allows a rapid measurement of water hardness and can be used to determine changes in hardness. The direct potentiometric method is not recommended for the ion-selective electrode but an indirect potentiometric method involving ethylenediaminetetraacetic acid titration is recommended. The ion-selective electrode that is used is a liquid ion-exchange electrode that responds to the divalent ions magnesium and calcium. 

EDTA solution CioHi4N2Na208 2H2O, 0.025 mol/L for samples with S<20. Dissolve 18.61 g of ethylenediaminetetraacetate (disodium salt, dihydrated, analytical-reagent grade, a.g.) dried at 50 °C for 1 h) in distilled water and dilute to 2000 mL. Determine the exact titre by standardization with the magnesium standard solution. 

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