Peppermint oil is the fresh stem and leaf of the labrum mint, which is distilled by steam, then frozen, and partially debrained to produce the volatile oil.

　　Mint oil is colorless or light yellow clarifying liquid.

　　Have a special cool and refreshing aroma. Keep the day long and fade away.

　　Peppermint oil can be mixed with ethanol, chloroform or ether.

　　Peppermint oil

　　Relative density: should be 0.888 ~ 0.908 (appendix Ⅶ A).

　　Rotation: take this product, 1 dm tube, determined in accordance with the law (appendix Ⅶ E) - 17 ° ~ - 24 °.

　　Refractive index:

　　Should be 1.456 ~ 1.466 (appendix Ⅶ F).

　　1 drop of peppermint oil, 3 ~ 5 drops of sulfuric acid and a small amount of vanillin, should be orange red, then add water 1 drop, that is to turn purple.

　　Color:

　　Compared with the yellow 6 standard of the same volume, the peppermint oil should not be further.

　　Insoluble in ethanol:

　　Take 1ml of peppermint oil, add 70% ethanol and 3.5ml, and the solution should be clarified.

　　Heavy metal:

　　Peppermint oil 1 g, in accordance with the inspection method (appendix Ⅸ E 2), containing heavy metals shall not be ten over one million.

　　Ester content:

　　Peppermint oil for about 5 peppermint oil precision according to fixed, flask, and neutral ethanol (indicates a show neuter liquid) on the phenolphthalein 10 ml after mixing, add fluid of phenolphthalein indicator 2 drops, with ethanol system first liquid potassium hydroxide titration (0.1 mol/L) will be free acid neutralization, again the fluid system of precision and ethanol potassium hydroxide titration 25 ml (0.5 mol/L), water bath reflux after 1 hour, put the cold, add fluid of phenolphthalein indicator 0.5 ml, hydrochloric acid standard solution titration (0.5 mol/L) of the rest of the potassium hydroxide, a blank test at the same time, a quick.

　　Potassium hydroxide titration (0.5mol/L) per 1ml of ethanol is equivalent to 99.15mg of C12H22O2.

　　Menthol acetate (C12H22O2) should be calculated at 2.0 ~ 6.5% (g/g).

　　The total amount of alcohol:

　　Acetylation (1) : peppermint oil 0 ml, acetylated bottle, add 10 ml of vinegar anhydride and new investment system of 2 g, anhydrous sodium acetate with reflux condenser pipe, air in 145 + 3 ℃ oil bath heating within 75 minutes, take out the cold, 50 ml of water, water bath on, constantly shake, heat for 15 minutes, cool off.

　　Remove the acid from the bottom of the funnel.

　　When leave the acetylation of oil in turn with a saturated solution of sodium chloride and sodium carbonate saturated sodium chloride saturated solution and sodium chloride saturated solution 1 times each, each about 50 ml, washing with water, each about 50 ml, until lotion of phenolphthalein indicator show neuter liquid.

　　Will the acetylated oil 25 ml flask, anhydrous sodium sulfate for 3 g, plug, and keeps vibration wave make dehydration, to take 1 acetylated oil to join carbon disulfide 10 drops will not occur in the turbidity, reoccupy dry filter filtration.

　　(2) saponification: dry acetylated oil is about 2.5 g, precision, said in A 250 ml conical flask, precision and system of ethanol potassium hydroxide titration fluid (0.5 mol/L) 50 ml, according to tested items of ester content from the "water bath to reflux for 1 hour after", in accordance with the operation, with hydrochloric acid standard solution acetylated oil consumption (0.5 mol/L), quantity (ml) as A blank consumption of hydrochloric acid standard solution (0.5 mol/L), quantity (ml) as B, according to the following formula calculation, quick.

　　(B - A) x 0.07815

　　E total amount of alcohol % = ─ ─ ─ ─ ─ ─ ─ ─ x (1-0.2119 x ─ ─ ─) x 100% W - x 0.02 (B - A)

　　102100

　　Type in the

　　W is the weight of acetylated oil (g); E is the amount of ester in the test.

　　The total alcohol content of this product is calculated by the menthol (C10H20O), not less than 50.0% (g/g).

　　(the above is from baidu search.)