» Potassium Benzoate contains not less than 99.0 percent and not more than 100.5 percent of C7H5KO2, calculated on the anhydrous basis.
Packaging and storage Preserve in well-closed containers.
Alkalinity Dissolve 2 g in 20 mL of hot water, and add 2 drops of phenolphthalein TS: the pink color produced, if any, is discharged by the addition of 0.20 mL of 0.10 N sulfuric acid.
Water, Method I 921: not more than 1.5%.
Heavy metals 231 Dissolve 4.0 g in 40 mL of water, add, dropwise, with vigorous stirring, 10 mL of 3 N hydrochloric acid, and filter. Use 25 mL of the filtrate: the limit is 0.001%.
Assay Transfer about 600 mg of Potassium Benzoate, accurately weighed, to a 250-mL beaker. Add 100 mL of glacial acetic acid, stir until the assay specimen is completely dissolved, add 2 drops of crystal violet TS, and titrate with 0.1 N perchloric acid VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 16.02 mg of C7H5KO2.
Auxiliary Information Please check for your question in the FAQs before contacting USP.Chromatographic Column
USP32NF27 Page 1321
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.