Test for calcium, magnesium and phosphate in urine:

So the test for calcium, magnesium and phosphate in urine can be done with ease by the following methods.

Test for Magnesium in urine:

Chemicals Required:

• A concentrated solution of ammonia.
• Urine

Procedure:

• Take 5 ml of urine of urine in a test tube.
• Add 1 ml of a concentrated solution of ammonia.
• Heat to boil the test tube.

Observation:

A white flaky precipitate of phosphates of calcium and magnesium forms. Filter it. Discard the filtrate and dissolve the precipitate in 3 ml of 1% acetic acid.

Perform the following test on this solution for the presence of calcium and phosphate separately.

Test for calcium in urine:

Reagents:

• 2% potassium oxalate

Procedure:

• Take 1 ml of above solution in a test tube.
• Add 1 ml of 2% potassium oxalate in it.
• Mix thoroughly.

Observation:

A white precipitation of calcium oxalate is produced, indicating the presence of calcium in the urine.

Test for phosphate urine:

Reagents:

• Ammonium molybdate

Procedure:

• Take 1 ml of above solution in a test tube.
• Add 1 ml of ammonium molybdate reagent.
• Heat to boil.

Observation:

The formation of a yellow crystalline precipitate indicates the presence of phosphate in urine.

Note:

The urine on boiling evolves the CO2 which makes the reaction alkaline. This results in the formation of a precipitate of magnesium and calcium phosphates, which are re-dissolved by the addition of acetic acid. This distinguishes these salts from proteins, which on heating get coagulated and cannot be re-dissolved by the acetic acid.

Precautions:

• Wash the apparatus before and after the experiment.
• Carefully handle all the chemicals in the lab.
• Avoid urine touching with hands.
• Use forks for holding test tube.
• The test tube used should be clean neatly and free of any dirt and chemicals because we will not get the proper result then, so try to use a clean and clear test tube for correct result.