Potassium Carbonate
K2CO3 (anhydrous) 138.21

Carbonic acid, dipotassium salt.
Dipotassium carbonate [584-08-7].

Sesquihydrate 165.23
» Potassium Carbonate contains not less than 99.5 percent and not more than 100.5 percent of K2CO3, calculated on the dried basis.
Packaging and storage— Preserve in well-closed containers.
Identification— It responds to the tests for Potassium 191 and for Carbonate 191.
Loss on drying 731 Dry it at 180 for 4 hours: it loses not more than 0.5% of its weight.
Insoluble substances— Dissolve 1 g in 20 mL of water: the solution is complete, clear, and colorless.
Heavy metals 231 Dissolve 4.0 g in 10 mL of water, add 15 mL of 3 N hydrochloric acid, and heat to boiling. Add 1 drop of phenolphthalein TS, and neutralize with 1 N sodium hydroxide until the solution is faintly pink in color. Cool, and dilute with water to 25 mL: the limit is 0.0005%.
Assay— Transfer the dried potassium carbonate obtained in the test for Loss on drying to a flask with the aid of 150 mL of water, add 4 drops of methyl orange TS, and titrate with 1 N hydrochloric acid VS. Each mL of 1 N hydrochloric acid is equivalent to 69.11 mg of K2CO3.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Sujatha Ramakrishna, Ph.D.
(MDCV05) Monograph Development-Cardiovascular
USP32–NF27 Page 3336
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.