Assay Test Procedure for Calcium Carbonate by Titration Method | How to Test Calcium Carbonate Assay by Titration Method |
Definition of calcium
carbonate or what is calcium carbonate
Calcium is a mineral that is
found in foods, specifically dairy, and stored in bones and teeth in our body.
It is essential for growth and development of children and adolescents as it
maintains strong bones and teeth while also assisting in muscle contractions,
nerve stimulations and regulating blood pressure.
Instrument or equipment required
for analysis of assay content of calcium carbonate (CaCO3)
Analytical Balance
Pipette
Burette
Volumetric flask 250 ml
Digestion flask 250 ml
Watt man filter paper
Ultra sonicator
Chemical or regents required
for analysis of calcium carbonate (CaCO3)
Hydrochloric Acid
Patton reader indicator
10 % Sodium hydroxide
0.02 M EDTA Volumetric Solution
Chemical or Reagents
Preparation
10 % Sodium Hydroxide Solution
Weigh about 10 g of Sodium hydroxide
in a baker and slowly dissolved in cold water and make up to 100 ml.
Patton reader Indicator
Weigh about 1 g of Patton reader
indicator powder and mix with 99 g of sodium sulphate power and make a fin mixture.
0.02 M EDTA Solution
Dissolve 7.44 g of EDTA disodium salt
in water and make up to 1000 ml
Standardization: Accurately
weigh above 200mg of standard calcium carbonate (previously dried at 105ºC for
2 hours) and transfer to a 400 ml of water and swirl to form slurry. Cover the
beaker with watch glass and introduce 2ml of dilute Hydrochloric acid from the
pipette inserted between the lip of the beaker and the edge of watch
glass. Swirl the contents of beaker to dissolve calcium carbonate. Wash down
the sides of beaker, outer surface of pipette and watch glass with water to about
100ml while stirring the solution, preferably with the magnetic stirrer, add
about 3mL of EDTA disodium solution from a 50ml burette. Add 15ml of sodium
hydroxide TS and 300mg of hydroxyl naphthol blue, and continue the titration
with the EDTA disodium solution to a blue end point.
Normality of EDTA = Weight of
calcium carbonate (g) × 1000/100.09 ×
ml of EDTA consumed
Procedure
Weigh 500 mg of sample calcium
carbonate and transfer the sample into a 250 ml volumetric flask. Add 2 ml of
hydrochloric acid and dissolve the sample. Then make up to 250 ml with water.
Mix well and sonicate for 5 minutes.
Then filter through 0.45-micron
Watt man filter paper if required. Collect 50 ml of filtrate solution in a 250 ml
conical flask and add 2 mL of 10% sodium hydroxide and about 10 mg of Patton
reader indicator. Then titrate with 0.02M EDTA to the end point is blue colour.
Each ml of 0.02M EDTA is equivalent to 0.04008 mcg of calcium. Blank titration
shall be perform in the same manner, omitting the sample.
Calculation:
(T1-T2) × M ×
0.04008 × 250
Calcium (%) = -------------------------------------
W × 50
Calcium (%) × 100.0869
Calcium Carbonate (%) = ------------------------------------
40.08
Where,
T1 = Titre value of sample
T2 = Titre value of blank
M = Molarity of 0.02M EDTA
0.04008 = atomic weight of
calcium ×
10-3
100.0869 = Molecular weight of
Calcium Carbonate
40.08 = Molecular weight of
Calcium
W = Weight of sample in gram
Limit: Not less than 99.00 %
(W/W)
Where the Reference ?
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