Ethylenediaminetetraacetic acid titrations methods

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. 

Metal Content. Two common analytical methods for determining metal content are by titration and by atomic absorption spectrophotometry (aas). The titration method is a complexiometric procedure utilizing the disodium salts of ethylenediaminetetraacetic acid (EDTA). The solvent, indicator. 

Although the most sensitive line for cadmium in the arc or spark spectmm is at 228.8 nm, the line at 326.1 nm is more convenient to use for spectroscopic detection. The limit of detection at this wavelength amounts to 0.001% cadmium with ordinary techniques and 0.00001% using specialized methods. Determination in concentrations up to 10% is accomplished by solubilization of the sample followed by atomic absorption measurement. The range can be extended to still higher cadmium levels provided that a relative error of 0.5% is acceptable. Another quantitative analysis method is by titration at pH 10 with a standard solution of ethylenediaminetetraacetic acid (EDTA) and Eriochrome Black T indicator. Zinc interferes and therefore must first be removed. 

Ethylenediaminetetraacetic acid can be used as a reagent for the titration of Ti(lV). However, the reaction proceeds slowly, and the Ti(IV) species tend to hydrolyze during the titration, so that a back-titration method is necessary to make the complexometric method work properly [26]. 

The determination of calcium in meat products, especially in mechanically recovered (or separated) meat (MRM/MSM), is an important estimation of the amount of bone material included in the meat. The AOAC method describes an acid digestion of the sample and reaction of an aliquot of the filtered digest with excess ethylenediaminetetraacetic acid (EDTA) under alkaline conditions to form a chelated complex with calcium ion. The excess EDTA is then titrated with calcium carbonate using hydroxynaph-thol blue as indicator. 

Titrimetric methods based on the reaction of metal ions with a coordinating species (ligand) are more than 100 years old. If the ligand is attached to the metal by more than one functional group, it is said to be polyden-tate and the compound produced is called a chelate. The complexometric reagent that is easily the most widely used for the titration of unknown concentrations of metal ion is the hexadentate ligand ethylenediaminetetraacetic acid (EDTA), first recognized by Schwarzenbach in 1945. The structure of the molecule is... 

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