Method name: Nepeta paniculata—Determination of volatile oil—Volatile oil determination method

Application scope: This method uses the volatile oil determination method to determine the content of volatile oil in Nepeta paniculata.

This method is suitable for the determination of volatile oil content in Schizonepeta paniculata.

Principle of the method: Add an appropriate amount of water to the test sample in the volatile oil measuring device, heat it to boiling and keep it slightly boiling for 5 hours, then read the amount of volatile oil in the measuring device and calculate its content.

Reagents: sodium chloride

Instruments and equipment: 1. Instruments

1.1 Volatile oil tester: 1000mL (or 500mL, 2000mL) hard round-bottomed flask , connected to the volatile oil measuring device, and the upper end of the volatile oil measuring device is connected to the reflux condenser tube. All the above parts are connected with glass grinding joints. The measuring device should have a 0.1mL scale. All instruments should be thoroughly washed, and the joints should be checked to see if they are tight to prevent volatile oil from escaping.

Note: The bifurcation of the branch pipe of the volatile oil measuring device in the device should be parallel to the baseline.

Sample preparation:

Operation steps: Precisely measure 10 mL of the test sample, place it in a separatory funnel, add 100 mL of saturated sodium chloride solution, and shake for 1 to 2 minutes. Leave it for L~2 hours, separate the supernatant liquid, transfer it to a round-bottomed flask, wash the separatory funnel with hot water several times, put the washing liquid into the round-bottomed flask, add 300~500mL of water and a few glass beads, shake and mix Finally, connect the volatile oil meter and the reflux condenser. Add water from the upper end of the condenser tube until it fills the graduated part of the volatile oil meter and overflows into the flask. Place it in an electric heating mantle or use other suitable methods to slowly heat it to boiling, and keep it at a slight boil for about 5 hours. When the amount of oil in the measuring device no longer increases, stop heating, leave it for a while, open the piston at the lower end of the measuring device, and slowly release the water. , until the upper end of the oil layer reaches 5mm above the 0 line of the scale. Leave it for more than 1 hour, then open the piston so that the oil layer drops to its upper end just flush with the 0 line of the scale, read the amount of volatile oil, and calculate the content (%) of volatile oil in the test sample.