Assay—
Transfer about 100 mg of Oxyquinoline Sulfate, accurately weighed, to an iodine flask, add 30 mL of glacial acetic acid, 25.0 mL of 0.1 N bromine VS, 10 mL of potassium bromide solution (3 in 20), and 10 mL of hydrochloric acid, immediately insert the stopper, mix, and allow to stand for 15 minutes, protected from light. Quickly add 10 mL of potassium iodide solution (1 in 10) and 100 mL of water, taking precautions against the escape of bromine vapor, at once insert the stopper, and shake the mixture thoroughly. Remove the stopper, and rinse it and the neck of the flask with a small quantity of water so that the washing flows into the flask. Shake the mixture thoroughly, and titrate the liberated iodine with 0.1 N sodium thiosulfate VS, adding 3 mL of
starch TS as the endpoint is approached. Perform a blank determination (see
Residual Titrations under
Titrimetry 
541
). Each mL of 0.1 N bromine is equivalent to 4.855 mg of (C
9H
7NO)
2·H
2SO
4.
;)
