Assay : Boil mL of N hydrochloric acid with about600 mg of Calcium Undecylenate, accurately weighed, for 10 minutes, or until the undecylenic acid layer is clear, adding water, as necessary, to maintain the original volume. Transfer the mixture, with the aid of water, to a 500-mLseparator. Dilute with water to about 75 mL, and extract with two 100-mLportions of solvent hexane. Wash the combined extracts with water until the last washing is neutral to litmus, add the washings to the original water layer. Cool, add 3 drops of methyl orange, and titrate the excess hydrochloric acid with N sodium hydroxide. Perform a blank determination. Each mL of sodium hydroxide is equivalent to mg of C22H38O4Ca.
Loss on drying : Dry it at 105 for 2 hours: it loses between % and % of its weight.
Particle size, Method : Test in accordance with this procedure, except to use not more than 25 g, and except that a single No. 100 sieve is used and is to be shaken for not less than 30 minutes or until sifting is practically complete: not less than % of it passes through a No. 100 sieve.
Limit of free undecylenic acid : Transfer 10 g of Calcium Undecylenate, accurately weighed, to a 400-mL beaker, add 250 mL of solvent hexane, and mix for 2 hours using a magnetic stirrer. Filter into a 500-mL flask, evaporate with the aid of a current of air to about 20 mL, and add 100 mL of neutralized alcohol. Add 3 drops of phenolphthalein TS, and titrate with N sodium hydroxide. Each mL of N sodium hydroxide is equivalent to mg of C11H20O2: not more than % is found.