Assay
Place about 5 g of Lotion, accurately weighed, in a conical flask. Add 25 mL of alcohol and 2 drops of
phenolphthalein TS. Cool the solution to about 15
, and titrate quickly with 0.1 N sodium hydroxide to a slight pink color. Add 50.0 mL of 0.5 N alcoholic potassium hydroxide VS, connect the flask to a reflux condenser, and boil gently for 1 hour. Cool, promptly add
phenolphthalein TS, and titrate with 0.5 N hydrochloric acid VS. Perform a blank determination (see
Residual Titrations under
Titrimetry 541). Each mL of 0.5 N alcoholic potassium hydroxide is equivalent to 106.1 mg of C
14H
12O
2.