Potassium Carbonate
K2CO3(anhydrous)
138.21
Carbonic acid,dipotassium salt.
Dipotassium carbonate [584-08-7].
Sesquihydrate 165.23
»Potassium Carbonate contains not less than 99.5percent and not more than 100.5percent of K2CO3,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification—
It responds to the tests for Potassium á191ñand for Carbonate á191ñ.
Loss on drying á731ñ—
Dry it at 180
for 4hours:it loses not more than 0.5%of its weight.
for 4hours:it loses not more than 0.5%of its weight.
Insoluble substances—
Dissolve 1g in 20mLof water:the solution is complete,clear,and colorless.
Heavy metals á231ñ—
Dissolve 4.0g in 10mLof water,add 15mLof 3Nhydrochloric acid,and heat to boiling.Add 1drop of phenolphthalein TS,and neutralize with 1Nsodium hydroxide until the solution is faintly pink in color.Cool,and dilute with water to 25mL:the limit is 0.0005%.
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Assay—
Transfer the dried potassium carbonate obtained in the test for Loss on dryingto a flask with the aid of 150mLof water,add 4drops of methyl orange TS,and titrate with 1Nhydrochloric acid VS.Each mLof 1Nhydrochloric acid is equivalent to 69.11mg of K2CO3.
Auxiliary Information—
Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(PA5)Pharmaceutical Analysis 5
USP28–NF23Page 1583
Phone Number:1-301-816-8305