Packaging and storage—
Preserve in well-closed, light-resistant containers. Store at 25
, excursions permitted between 15
and 30
.
Identification—
B: Ultraviolet Absorption 
197U
—
Solution:
5 µg per mL.
Medium:
alcohol.
Absorptivities at 250 nm, calculated on the dried basis, do not differ by more than 3.0%.
Loss on drying 731—
Dry it over silica gel for 4 hours: it loses not more than 0.3% of its weight.
Ordinary impurities 466—
Test solution:
methanol.
Standard solution:
methanol.
Eluant:
chloroform.
Visualization:
1.
Assay—
Accurately weigh about 150 mg of Menadione, and transfer to a 150-mL flask. Add 15 mL of glacial acetic acid and 15 mL of 3 N hydrochloric acid, and rotate the flask until the Menadione is dissolved. Then add about 3 g of zinc dust, close the flask with a stopper bearing a Bunsen valve, shake, and allow to stand in the dark for 1 hour, with frequent shaking. Rapidly decant the solution through a pledget of cotton into another flask, immediately wash the reduction flask with three 10-mL portions of freshly boiled and cooled water, add 0.1 mL of orthophenanthroline TS, and immediately titrate the combined filtrate and washings with 0.1 N ceric sulfate VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N ceric sulfate is equivalent to 8.609 mg of C11H8O2.
;)
