Spearmint and Caraway Oils: (+)- and (-) – Carvones
Compare (+)- carvone from caraway oil to (-)- carvone from spearmint oil, using gas chromatography. Experimental
Odor: Smell containers of spearmint and caraway oil and two carvones. Analytical Gas Chromatography: Put five individual samples by different group members into Gas Chromatograph to calculate the percent composition. Claudia tested S- (+)- carvone and R- (+) – Limonene, Daniel tested Spearmint oil (pure), Greg tested R- (-)- carvone and I tested Caraway oil (pure). Refractive Index: Obtained the refractive index on a small volume of liquid. Cleaned lens with a Kim wipe, put drops on the lens, closed the top and looked through the hole to get the refractive index. Did this with five different samples of pure spearmint oil, S (+) carvone, pure caraway oil, Limonene, R (-) carvone.
Odor: The caraway oil smelled lemony like a lime peel. Spearmint smelled like spearmint gum and the S (+) carvone and R (-) carvone smelled like vinegar. The retention times and percent composition of the components of the two oils is going to have two peaks. Spearmint had a retention time of .533 and had 21.86 % area that had limonene present and at 2.383 it had 67.49 % of carvone present in the sample. Pure caraway oil had a retention time of .600 and had 47.03% of limonene and at 2.458 47.77% of carvone was present in the sample. The refractive index for both carvones is S (+) carvone had a refractive index of 1.4994 R (-) carvone had a refractive index of 1.4999. The reference values at 200 is equal to 1.4989. The differences between the values and the referenced values are -.0005 for S (+) carvone and -.001 for R (-) carvone. There is a very small difference between the two values.
According to http://www.mintrubbing.org/themintplant.pdf, “Peppermint essential oil has been used to treat indigestion, headaches, colic, gingivitis, irritable bowel syndrome, spasms and rheumatism....
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