Estimation of calcium gluconate by Complexometric titration
Calcium gluconate is a calcium salt of gluconic acid and is commonly used as a calcium supplement. Complexometric titration can be used to determine the amount of calcium present in a calcium gluconate sample.
In complexometric titration, a chelating agent, such as ethylenediaminetetraacetic acid (EDTA), is used to form a complex with the calcium ions in the sample solution. The addition of a metal ion indicator, such as Eriochrome Black T, helps to indicate the endpoint of the titration.
To carry out the titration, a known quantity of the calcium gluconate sample is dissolved in water, and the pH is adjusted to around 10 with the addition of ammonium hydroxide. Then, a small amount of Eriochrome Black T indicator solution is added to the solution, and the titration is initiated by adding the EDTA solution.
As the EDTA solution is slowly added, it forms a complex with the calcium ions, and the color of the solution changes from red to blue. The endpoint of the titration is reached when all the calcium ions have reacted with the EDTA, and the solution turns from blue to pink.
The amount of EDTA solution added to the sample can be used to calculate the amount of calcium present in the sample, using stoichiometry of the reaction.
It is important to ensure that the calcium gluconate sample is completely dissolved in water and free from any other impurities that may affect the accuracy of the titration. Additionally, the EDTA solution should be standardized against a known quantity of calcium before use to ensure accurate results.
Overall, complexometric titration can be a reliable and accurate method for the estimation of calcium gluconate, and can be used in the pharmaceutical industry and research laboratories.
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