Ethylenediaminetetraacetic acid titrations Indicator

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. 

Although mercury seldom is used as an indicator electrode in redox titrations (because it is so readily oxidized), it is used extensively for potentiometric titrations with complexing agents such as ethylenediaminetetraacetic acid... 

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... 

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. 

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