» Peppermint Spirit contains, in each 100 mL, not less than 9.0 mL and not more than 11.0 mL of peppermint oil.
Macerate the peppermint leaves, freed as much as possible from stems and coarsely powdered, for 1 hour in 500 mL of purified water, and then strongly express them. Add the moist, macerated leaves to 900 mL of alcohol, and allow the mixture to stand for 6 hours with frequent agitation. Filter, and to the filtrate add the oil and add alcohol to make the product measure 1000 mL.
Packaging and storage Preserve in tight containers, protected from light.
Alcohol content, Method II 611: between 79.0% and 85.0% of C2H5OH.
Assay Transfer 5.0 mL of Spirit to a Babcock bottle, graduated to 8%, add 1.0 mL of kerosene, and mix. Add saturated calcium chloride solution, acidified with hydrochloric acid, almost to fill the bulb of the bottle. Rotate the bottle vigorously to ensure mixing, and then add a sufficient quantity of the calcium chloride solution to bring the separated oil into the neck of the bottle. Centrifuge at about 1500 rpm for 5 minutes, and read the volume of oil in the stem. Subtract five divisions for the kerosene added, and multiply the remaining number of divisions by 4.2 to obtain the volume, in mL, of peppermint oil in 100 mL of the Spirit.