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Prepared at the 27th JECFA (1983), published in FNP 28 (1983) and in FNP 52 (1992) |
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SYNONYMS |
Citric acid triammonium salt; ammonium citrate tribasic; INS No. 380 |
DEFINITION | |
Chemical names |
Triammonium citrate, triammonium salt of 2-hydroxypropan-1,2,3-tricarboxylicacid |
C.A.S. number |
3458-72-8 |
Chemical formula |
C6H17N3O7 |
Structural formula |  |
Formula weight |
243.22 |
Assay |
Not less than 97.0% |
DESCRIPTION |
White crystals or crystalline powder |
FUNCTIONAL USES |
Buffering agent |
CHARACTERISTICS | |
IDENTIFICATION | |
Solubility |
Freely soluble in water |
Test for citrate |
Passes test |
Test for ammonium |
Passes test |
PURITY | |
Oxalate |
Not more than 0.04% |
Arsenic |
Not more than 3 mg/kg (Method II) |
Lead |
Not more than 5 mg/kg |
Heavy metals |
Not more than 10 mg/kg Test 2 g of the sample as directed in the Limit Test (Method II) |
METHOD OF ASSAY |
Dissolve about 3.5 g of the sample, accurately weighed, in 50 ml of water, add 50 ml of 1 N sodium hydroxide, boil for 15 min or until ammonia ceases to be evolved, add sufficient 1 N sulfuric acid to make the solution acid to phenolphthalein TS, boil for 5 min, cool, and titrate with 1 N sodium hydroxide, using phenolphthalein TS as an indicator. Each ml of 1 N sodium hydroxide is equivalent to 81.07 mg of C6H17N3O7. |