Osmanthus Adulteration

October 17 2019 1 Comment(s)

Osmanthus absolute is a rare and expensive product on the market. This is partially due to the compound ionone, which is a perfume quality molecule. Due to the price, osmanthus absolute is often adulterated. This absolute is usually adulterated with a carrier or cooking oil, however most of the compounds in osmanthus are commercially available on the market, so synthetic compounds may also be added. Fractionated geraniol from palmarosa and linalool from ho wood are also readily attainable. Linalool oxide cis and trans can easily be produced from oxidized linalool.

Due to the ease of adulterating this absolute, it is essential to have a lab test it for purity. One interesting fact about osmanthus is that it contains several chiral molecules. Essential oils can have chiral and non-chiral molecules. A molecule is chiral when light passes through one molecule in a clockwise direction and passes through a different molecule in a counter-clockwise direction. For example, limonene is a chiral molecule. If light passes through a limonene molecule in a clockwise direction, then it is D-limonene or (+)-limonene. If light passes through a different limonene molecule in a counterclockwise direction, then it is called L-limonene or (-)-limonene.

D limonene L limonene

Essential oils can have D and L molecules. A GC-MS can identify total compounds in an oil, but the Chiral GC can determine the exact percentage of D and L molecules. For example, there can be 6% of linalool in an oil, however the chiral GC can determine that 80% of that linalool is L-linalool and 20% is D-linalool. Chirality is constant in an oil within a small range. So an oil can have 6-15% of linalool, however it will always have 79-81% of L-linalool and 19-21% for D-linalool. If an oil has a chiral molecule in amounts far outside of those small ranges, then we can determine that it has been adulterated. APRC offers Chiral GC testing because we know how important it is to determine the purity of an oil.

Comments and responses

  • sandi ewing:

    05 Nov 2019 05:05:00

    Love your research information on essential oils. It’s very interesting.

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