Assay of Calcium Citrate

Reagent required

3N Hydrochloric acid
0.05M Disodium Edetate
Sodium hydroxide solution
Hydroxy naphthol blue

Procedure

Dissolve about 350 mg of Calcium Citrate, previously dried at 150°C to constant weight and accurately weighed, in a mixture of 10 ml of water and 2 ml of 3N hydrochloric acid, and dilute with water to about 100 ml. While stirring, add about 30 ml of 0.05 M Edetate Disodium from a 50 ml burette. Add 15 ml of 1N sodium hydroxide and 300 mg of hydroxy naphthol blue as an indicator, and continue the titration to a blue endpoint. Each ml of 0.05 M Edetate Disodium is equivalent to 8.307 mg of Ca3(C6H5O7)2.
Calculation

                      V x M x F                 100
% Assay = -------------------- x----------------
                      0.05 x W               (100-LOD)
Where,
V = Blank reading – Sample reading
M = Molarity of 0.05M Disodium Edetate
F = Factor
W = Weight of sample