Calcium Citrate USP Grade Specifications:
C12H10Ca3O14-4H2O --- 570.49
1,2,3-Propanetricarboxylic acid, 2-hydroxy-, calcium salt (2:3), tetrahydrate;
Calcium citrate (3:2), tetrahydrate CAS 5785-44-4

DEFINITION
Calcium Citrate contains four molecules of water of hydration. When dried at 150C to constant weight, it contains NLT 97.5% and NMT 100.5% of Ca3(C6H5O7)2.

IDENTIFICATION
A.
Analysis: Dissolve 0.5 g in a mixture of 10 mL of water and 2.5 mL of 2 N nitric acid. Add 1 mL of mercuric sulfate TS, heat to boiling, and add 1 mL of potassium permanganate.
Acceptance criteria: A white precipitate is formed.
B.
Sample: 0.5 g of Calcium Citrate
Analysis: Ignite completely the Sample at as low a temperature as possible, cool, and dissolve the residue in dilute glacial acetic acid (1:10). Filter, and add 10 mL of ammonium oxalate to the filtrate.
Acceptance criteria: A voluminous white precipitate that is soluble in hydrochloric acid is formed.

ASSAY
Procedure
Sample solution: Dissolve 350 mg of Calcium Citrate, previously dried at 150C to constant weight, in 12 mL of 0.5 M hydrochloric acid, and dilute with water to about 100 mL.
Analysis: While stirring the Sample solution, add 30 mL of 0.05 M edetate disodium from a 50-mL burette. Add 15 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue and continue the titration to a blue endpoint. Each mL of 0.05 M edetate disodium is equivalent to 8.307 mg of calcium citrate (Ca3&(C6H5O7)2).
Acceptance criteria: 97.5% to 100.5% on the dried basis

Calcium Citrate FCC Food Grade Specifications
Tricalcium Citrate
CH2(COO)C(OH)(COO)CH2COO2Ca3
Ca3(C6H5O7)2-4H2O Formula weight 570.50
INS: 333 CAS: 5785-44-4

DESCRIPTION
Calcium Citrate occurs as a fine, white powder. It is very slightly soluble in water, but it is insoluble in alcohol.

REQUIREMENTS
Identification:
A. Dissolve 500 mg of sample in 10 mL of water and 2.5 mL of 1.7 N nitric acid, add 1 mL of mercuric sulfate, heat to boiling, and then add potassium permanganate TS. A white precipitate forms.
B. Completely ignite 500 mg of sample at as low a temperature as possible, cool, and dissolve the residue in a mixture of 10 mL of water and 1 mL of glacial acetic acid. Filter, and add 10 mL of ammonium oxalate to the filtrate. A voluminous, white precipitate forms that is soluble in hydrochloric acid.
Assay: Not less than 97.5% and not more than 100.5% of Ca3(C6H5O7)2 after drying.
Fluoride: Not more than 0.003%.
Lead: Not more than 2 mg/kg.
Loss on Drying: Between 10.0% and 14.0%.