Chromatographs (gas chromatography) show the relative amounts of the various organic components that make up essential oils. The primary types of components include:

In simple terms, when choosing an essential oil, one wants high therapeutic value and low toxicity. There are many different compounds within each of the major categories - altogether there are several hundred individual chemical substances that are found in essential oils. This makes it difficult to evaluate oils chemically. Even though a chromatograph may show only a few of the constituents of an oil, one still needs knowledge of many individual substances and their properties to read a chromatograph.

However, an illustration will show some of the basics: Below are two chromatographs (with reports) - one is for Lavender Provence and one is for Lavender Dalmatian. I prefer the Lavender Provence.
Here is why: A "good" Lavender contains a high proportion of esters and alcohols and a low proportion of camphor. The esters are especially prized in Lavender. "The constituents of different species differ in their content of the ester, linalyl acetate due to altitude. If lavender is grown above 2,000 feet, the ester content is increased, producing a more valuable oil." - quoted from the textbook for Aromatherapy Certification of the Australasian College of Herbal Studies.

Both the Provence and Dalmatian Lavenders are high in Linalool - a terpenoid alcohol that is low in toxicity and has good antiviral and antibacterial properties. Both are also low in camphor, which is a ketone and therefore a strong irritant. However even a quick glance at the charts shows that the Lavender from Provence is MUCH higher in Linalyl Acetate, an ester which is very low in toxicity and is highly valued for it's therapeutic effects. It is Linalyl Acetate which gives Lavender its' famous calming properties. Therefore, while either of these lavenders will have good antiviral and antibacterial properties, the Lavender Provence has outstanding calming and antispasmodic properties whereas the Lavender Dalmatian will have a less calming effect.

The Lavender Provence used by SomaTherapy Essential Oils costs the company, Dreaming Earth Botanicals, considerably more than the Lavender Dalmatian but we feel that the very superior quality of the Lavender Provence is worth the extra cost even though profits might well be higher if Dreaming Earth sold the cheaper oil.

*This information is provided for educational interest and is not intended to diagnose, treat, or cure any disease.

Copyright © 2010 Joie Power, Ph.D. / The Aromatherapy School  |  All Rights Reserved

This article, "Gas Chromatography: A Simple Explanation" was originally published for Dreaming Earth Botanicals, LLC

Dr. Joie Power is a retired, board certified neuropsychologist. She is a former Assistant Professor of Neurosurgery at the Medical College of Georgia and has over 20 years of clinical experience in both in- and out-patient settings. Her extensive studies in aromatherapy and other alternative healing methods include studies with Dr. Jane Buckle (aromatherapy) and Patricia Kyritsi Howell (herbal studies). She is founder and former owner of Dreaming Earth Botanicals (SomaTherapy Essential Oils) and an internationally known writer and teacher in the field of aromatherapy. Dr. Power grew up on a flower farm with grandparents who were dedicated 'plant people'. In 2000 she left conventional medicine in order to pursue her love of all things botanical. Her approach to aromatherapy weaves together solid scientific training and extensive clinical skills with a holistic approach that honors body, mind, and spirit. She is also the author of the Aromatherapy Quick Study Guide, published by Barcharts, Inc. To read other articles by Dr. Power, click: Aromatherapy Articles

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