C6H5K3O7·H2O 324.41

1,2,3-Propanetricarboxylic acid,2-hydroxy-,tripotassium salt,monohydrate.
Tripotassium citrate monohydrate [6100-05-6].

Anhydrous 306.40 [866-84-2].

Packaging and storage— Preserve in tight containers.

Identification— Asolution (1in 10)responds to the tests for Potassium á191ñand for Citrate á191ñ.

Alkalinity— Asolution of 1.0g in 20mLof water is alkaline to litmus,but after the addition of 0.20mLof 0.10Nsulfuric acid,no pink color is produced by the addition of 1drop of phenolphthalein TS.

Loss on drying á731ñ— Dry it at 180for 4hours:it loses between 3.0%and 6.0%of its weight.

Tartrate— To a solution of 1g in 1.5mLof water in a test tube add 1mLof 6Nacetic acid,and scratch the walls of the test tube with a glass rod:no crystalline precipitate is formed.

Heavy metals,Method Iá231ñ— Dissolve 2g in 25mLof water,and proceed as directed for Test Preparation,except to use glacial acetic acid to adjust the pH:the limit is 0.001%.

Organic volatile impurities,Method Iá467ñ: meets the requirements.

Assay— Dissolve about 200mg of Potassium Citrate,accurately weighed,in 25mLof glacial acetic acid.Add 2drops of crystal violet TS,and titrate with 0.1Nperchloric acid VSto a green endpoint.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 10.21mg of C6H5K3O7.

Expert Committee:(DSN)Dietary Supplements:Non-Botanicals

USP28–NF23Page 1589

Phone Number:1-301-816-8389