GCMS…what? Part 2

So, now you have a GCMS report.  What can you learn from it?

Well, for most casual essential oil users, it’s pretty simple.  You don’t need to know what all of those chemical components do, or even worry about the percentages of them.  What you are mostly looking for is 1) purity, 2) stability, and 3) substitution.  Let’s talk about purity first.

I’m going to show you a Plant Therapy GCMS report in its entirety.  I’m using Plant Therapy for one main reason.  They are third party tested.  Why does this matter?  Well, follow the money.  Who stands to gain from a ‘fudged’ test report?  The essential oil distributor.  A third party company, on the other hand, would lose all credibility and could possibly face legal consequences for adjusting results.  So, while in-house testing is good, and better than none, it’s hard to judge purity because the ones who have the most to gain are the ones testing.  You would never buy a diamond ring off of some guy in the street and take his word that he tested it and it is pure.  Because he has something to gain!  You would meet said street jewelry hawker at a jeweler and have the jeweler test it because the jeweler has nothing to gain from the sale but if he lies about the purity, he would lose all credibility should word get out and people would be hesitant to purchase from his shop again.  So, third party testing is my preferred way to go.  Of the companies and test results I posted yesterday, Rocky Mountain Oils is also third party tested.  Several of the companies had summaries and it was unclear if they were third party or not.

So, you have downloaded the test results and you are looking at them.  This is what you will see – all 5 pages of gloriousness (for Sweet Orange, more or less pages depending on the oil):


Cover page and summary.  Also includes remarks from Robert Tisserand about the scent of the oil.  This is what I keep for my records because I don’t really need to know every. single. component in the oil, just the ones that make up the bulk of it.





So, I just ignore those last two pages because it’s been way too long since I have had chemistry and I do not remember what all of those mean.  Other than they are chemical signatures.  That’s about it.  But, the first two pages contain the testing company’s name (PhytoChemia), the oil tested (Citrus sinensis), and who the test was prepared for (Plant Therapy).  Then a whole bunch of names of chemical components and percentages and chemical families.  You can scan this, but what you really want to see is at the bottom of the graph, on the second page:


This is what you are looking for, the money shot.  The testing company’s conclusion is that this oil is pure and not adulterated, contaminated, or diluted.  (Oh, and if you are wondering why the total isn’t 100% right there at the bottom of the graph, it’s because some of the material is lost during testing, totally normal).

Now, you have verified purity, let’s check for stability.  This is really only important if you are replacing an oil you already have.  Let’s look at this summary again.  This is for their current batch they are shipping out.


You can see that the oil is 94.9% limonene and only has trace amounts of myrcene and a-pinene.  Now, let’s say you are replacing an oil you purchased last year.  Here’s that test report:


You can see this one has 0.1% less limonene and 0.1% less myrcene and the same a-pinene.  Relatively small change.  This is pretty consistent with citrus oils.  But other oils, like frankincense, thyme, chamomile, and others can change dramatically due to climate and weather conditions.  So checking the test results from your older oil will help determine if this new one will do about the same thing as the one you currently have.  Large changes (5% or more on the bigger components) can create a vastly different outcome and have different therapeutic effects and safety concerns.

Another reason you may want to become more familiar with GCMS reports is to get to know some of your favorite components and be able to substitute.  Limonene is the main component in all citrus oils, their slightly varying effects is completely due to the 6-or-so% different minor components.  But you know all citrus oils are going to have very similar effects – immune support, anti-inflammatory, antibacterial, antioxidant.  So, if you want to make a recipe, but need to swap something out, finding something with similar component values can make the swap seamless.

Aromatics International has a neat search feature on the side of their website where you can search for chemical components.  For example, my recipe calls for Black Spruce and I just don’t have it.  And I have such a huge collection, I don’t really want to buy another oil for one recipe.  So I look up the GCMS for Black Spruce: organic-black-spruce-essential-oil-for-aromatherapy-_-aromatics
So, the largest component is in the bottom right corner – bornyl acetate at 24%.  I always start with the biggest, and if I can’t find something with that, then I move to smaller ones.  So, on the left side of the screen at Aromatics International is a search feature.  One of the options is chemical component.  Just choose the chemical component you are looking for and the minimum (and optional maximum) percent:


And then search results come up and you have other oil options that you may have in your arsenal already!  I could look at the GCMS for all of these to find the closest one, but they are all conifers, so they will all have a-pinene, so for me, that would be close enough.



So, that is why GCMS reports are important, even for the casual user!  Purity, stability, and substitution!  You do not have to know what any of these components do to use these reports.  They aren’t just for chemists or Certified Aromatherapists, they matter to you as a user!

Happy Researching!

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