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Determination of Calcium Oxalate by Titration

In this determination of calcium oxalate by titration post we briefly summarise about: principle, reagents requirements, calcium content in cow milk procedure, result, application and limitations of determination of calcium oxalate by titration.

Determination of Calcium Oxalate by Titration

KMnO₄ titration Method is a simple and quick way to determine the amount of calcium content in cow milk. Allow the milk and ammonium oxalate to stand at room temperature overnight. Centrifuge the calcium content in cow milk and carefully drain the supernatant, use the liquid part of the sample for the KMnO₄ titration.

Principle

Calcium content in cow milk is precipitated as calcium oxalate with ammonium oxalate (Magnesium is not precipitated as the conditions are selected to increase the solubility of magnesium oxalate).

The precipitate was washed with dilute ammonia to remove the excess ammonium oxalate and then dissolved in normal sulphuric acid. The oxalic acid formed was titrated with permanganate solution. The end point of KMnO₄ titration was indicated by the formation of pink colour stable for at least 30 seconds.

Requirements

Materials

1. Centrifuge

2. Centrifuge Tube

3. Burette

4. Burette stand

5. Water bath

Chemicals

1. Ammonia

2. Ammonium Oxalate

3. Oxalic Acid

4. Potassium Permanganate

Reagents

1. Ammonium oxalate solution (4 %): 4g of ammonium oxalate dissolved in 100ml of distilled water.

2. Ammonia solution (2%): 2ml of ammonia of specific gravity 0.88 is diluted to 100ml with distilled water.

3. Potassium permanganate (0.1N): This is prepared by dissolving 3.16 g of potassium permanganate in 1 litre of distilled water.

4. Standard oxalic acid solution (0.1N): It is prepared by dissolving 630mg of oxalic acid in 100ml of distilled water.

Procedure

1. Into each of the two centrifuge tubes pipetted out 2.0 ml of distilled water. 20 ml of milk and 1.0 ml of ammonium oxalate, mixed the tubes and allowed to stand overnight at room temperature.

2. Centrifuge for 10 minute of 2000 rpm and carefully drained the supernatant. Inverted the tubes and allowed to drain on a pad of filter paper for 3 minutes. Added 3.0 ml 2% ammonia drain the sides of the solution. This process was repeated until the precipitate was washed completely and supernatant gave no precipitate with calcium chloride.

3. Pipetted out 2.0 ml of normal sulphuric acid rotating the tubes to wash down, and then placed the tubes in water bath for 5 mins at 70-80°C to dissolve the precipitate.

4. Removed centrifuged and titrated the contents with 0.01N potassium permanganate solution in a burette till a pale pink was got. Which persist for about a minute. Repeat the titration with duplicate tubes.

5. Performed a blank titration with 2.0 ml of normal sulphuric acid. Kept in water bath for 5 mins and titrated with potassium permanganate to pink colours the difference between the two titre values gives the volume of 0.1N kmno4 required to titrate calcium oxalate.

Calculation

KMnO₄ Titration

0.1ml of 0.01N KmnO4 of calcium

 Volume of 0.01N KMno4 required by 2ml of blank = —————-

Volume of 0.01N KMno4 required by = ———————

2ml of milk contains =

100ml of milk contains = (_____x_____)/20

Result

The calcium content in cow milk 100 ml milk was found to be ___________.

We hope calcium content in cow milk protocol helps you in knowing principle, reagents requirements, calcium content in cow milk procedure, result, application and limitations of calcium content in cow milk.

Further Readings

Reference