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Spotting Adulterated Essential Oils with GC, Dr. Kevin Dunn
Yesterday we talked about how to use GC to tell what’s in an essential oil. This morning we are going to talk about resources to find out what ought to be in an essential oil. So I need to first talk about what is an essential oil. They’re extracted by different methods. If it is a citrus oil, like orange oil or lemon oil, it’s pressed out of the peel. Most essential oils are distilled and they are two types, hydro-distillation is you basically make a soup, you boil the steam away, condense the steam and the oil separates from the condensed steam. There is also steam distillation, which is slightly different. The plant material is not immersed in the boiling water but the steam passes through the plant material and then is collected. There are similar things that are not essential oils but they are related. So an enfleurage is you take plant material and soak it in something like vegetable oil and then you extract it with ethanol and then boil the ethanol away and what’s left behind is an absolute. You can also have solvent extraction where you use something like hexane to extract the volatile materials, the hexane evaporates leaving behind an absolute. And finally, there are super critical fluid extraction where you soak the plant material in carbon dioxide, liquid carbon dioxide at high pressure. When you release the pressure the carbon dioxide all evaporates and it leaves behind the extract. So what do I mean by adulteration? Adulteration is inclusion in a product of anything that really doesn’t belong in the product. So it might be intentional, it might be a supplier trying to cut cost by selling you something that is only 50% of what you think it is. It might be unintentional, maybe as a part of the processing, there’s something introduced to the oil that doesn’t belong there. So we could have dilution with less expensive solvents like hexane or di-ethyl thiolate. We could have blending with region specific oils so you could have bourbon geranium cut with Chinese geranium, which is a less expensive oil. You could have blending oils from different parts of the plant. Cinnamon comes in two kinds, there is the leaf oil and the bark oil and they are sold as separate products but if one were blended together and sold as the bark oil for example, that would be an adulteration. You could have blending of oils from different species, lavender and lavendin smell very similar. Lavendin is the cheaper oil so you could adulterate lavender oil by including some lavendin with it. You could blend oils from unrelated species so geranium and lavender both have linalool and linalyl acetate. You could cut lavender oil with geranium oil. You could blend oils with aromic chemicals that are present and authentic oils but not present in that particular oil, or actually in this case adding linalool to lavender oil, but you might cut lavender oil with linalool, something that belongs there but not in the proportion that it belong there. You could add things to the oil that really don’t belong there, so benzyl alcohol doesn’t belong in clove oil, but if you blend clove oil with benzyl alcohol, it smells okay, it smells like clove oil, but the benzyl alcohol is not a natural component of clove oil. Also you could have contaminations, unintentional contaminations from the processing of the sample. So what should be there? The problem is the composition varies by species, by region, by season, by extraction method and the plants are grown in the field and then are shipped to a distiller who distills them and a wholesaler then would combine lots of oil from different distillers so there is a possibility for adulteration at any of those steps. So the resources I use Essential Oils Analysis by Kubeczka, is a $615 book, a really really good book. I highly recommend it, but this is also a good book. So, Essential Oil Safety, the title makes you think it is just about safe handling of essential oils, but in fact it includes a lot of information about what should be in lavender oil. That’s only $95. There is Essential Oil University, this is a web site that is subscription based and you pay $100/year and you have access to thousands and thousands of GC reports for essential oils. And finally, this is the most expensive. ISO is an organization whose whole purpose in life is to make up rules for what should be in different things, peanut butter or whatever. They are the most expensive because they have a different spec for each essential oil and each one costs $100 or more and so that is pretty expensive. So ISO puts out an exclusive spec. They are trying to exclude things that aren’t genuine, so they make a very restrictive definition. For example, in lavender oil they specify that it should be between 20 – 43% linalool, 25% and 47% linalyl acetate and they have eight or ten more specs for different compounds, all that should be in lavender oil. Of the 42 lavender specifies in the Essential Oil University data base, 22 are excluded by the ISO spec. So these are all genuine oils but the ISO spec is so restrictive that it marks as out of spec 22 of the 42 genuine lavender oil samples. So the goal of this is to accept as genuine only typical lavender oils I’m going to talk about inclusive spec. So I have performed a statistical analysis of the essential oils on the Essential Oil University data base. I have generated the 95% reference interval, that’s an interval within which 95% of the samples fall, and you will see that graphically in a minute, even then going to reject 5% of the genuine lavender oil samples. For example, the 95% spec says linalool should be between 9% - 50% and lynalyl acetate between 4% - 57%. You are all looking puzzled right now. I’m going to show you a picture which hopefully will make it a little bit clearer. So this is on one axis lynalyl acetate, on the other axis linalool. This is the composition of an essential oil along these two axes, and the green box in the middle is the ISO spec. The larger box around it is the 95% reference interval and if you count the dots there are 42 of them. Those are the 42 lavender oils in the Essential Oil University data base and you see that many of them are excluded, they are outside of the ISO spec; but 95% of them are inside the larger green box which is the 95% reference interval. The idea of a reference interval is used in medicine a lot. For example I get a prostrate exam every year and they give me a report about my level compared to the population and they are two things they don’t want to do. They don’t want to tell me I have cancer when I don’t and they don’t want to not tell me if I have cancer when I do. So they use a 95% reference interval. 95% of normal healthy people will fall within that interval, 5% of normal healthy people will fall outside the interval. We have the same thing going on here that 95% reference interval will include more genuine oils than the ISO spec does, but at the risk of also including some oils that might not be genuine. Now imagine, this is a two dimensional graph, it’s got linalyl acetate versus linalool. Imagine now a 12 dimensional graph because we don’t just look at two components, we look at 8, 10 or 12 different components. So I’m going to give some examples now, this is our analysis of a lemongrass oil. On the left is the ISO spec. in the middle is the 95% reference interval and I have highlighted in red anything that is out of spec. On the far right is our analysis of this lemongrass oil and we find that neral in lemongrass should be between 25% - 35% by the ISO spec. We find it at 35.6%. Now is that a problem? What do you think? So there are a couple of reasons why I don’t consider that a problem. One is I look at the 95% reference interval, it goes all the way to 40%, so I’m clearly within that. Also, if I do this analysis ten times in a row, one time it is going to be 35.6%, the other time it will be 35.4% and another time it might be 34.9%. There is variation from one analysis to the other, so I don’t consider that out of spec. Similarly with geranial, should be 35% and 47%, we find it at 47.8%. Again I don’t think that’s a problem and so I would flagged this lemongrass oil as genuine. Here’s a palmarosa. Here we have some things out of spec, both by the ISO and by the 95% reference interval. The areas that need to be flagged are geranial, should be between .2% and 6% and we find it at .9%. It’s also out of spec for the reference interval. We also have a problem with caryophyllene at 3.6% compared to 2.5% or 2%. You know those are two specs out of a long list and so given the natural variation between oils, this is another oil that I didn’t flag as problematic. Also I have to think to myself, would somebody intentionally adulterate palmarosa oil with an extra .3% of geranial and I don’t think that’s a very reasonable suspicion to have. Here’s a juniper berry oil and it fails nearly all of the ISO specs. I won’t go through them one by one but if you look at the one that is problematic, the very first one is alpha-pinene, we find it at 61.5% and the ISO spec is 45%. What do you think I should do with this one? It is within the 95% reference interval for everything and it is out of the ISO spec for nearly everything. Audience Sell it at a discount? Kevin: Yeah, maybe so, I’m not going to flag this as adulterated. There is nothing in it that doesn’t belongs there. The proportions are a little bit out of spec for the ISO, but within the spec for reference interval. I’m simply going to inform Essential Depot that this is a little bit unusual as a juniper berry oil, but it isn’t out of the larger spec. Here is a questionable lavender oil and the places where it has a problem, eucalyptol should be between 0% - 3% and we find it at 4%. This is within the 95% reference interval for just about everything. It is out of spec for the ISO and you might say well that’s kind of like the juniper berry oil, except for one thing and that’s the very one at the bottom, diethylphalate, we find it at 1.3%. Diethylphalate doesn’t belong in any essential oil, so it’s not just that it’s something that should be there in the wrong percentage, it actually should not be there and I have to ask myself, would somebody add 1.3% diethylphalate to an essential oil. There is really no economic incentive there. So how did it get there, diethylphalate is a common plasticizer. Somewhere along the processing of this oil, I’ll bet it was in a plastic container or running through a plastic tubing of some plastic was used and the diethylphalate leached into the essential oil. I am going to flag this, even though it’s 95% reference interval just about everything. I’ am going to flag it because of the 1.3% diethylphalate. Part of my goal in doing these analyses is to protect Essential Depot by criticism by their competitors. If a competitor saw 1.3% diethylphalate, they would make hay out of it. Here’s a bergamot oil and the problem here, the ISO spec doesn’t list camphene at all. The 95% reference interval says between 0% - 2%. This is at 33%, a third of the sample is camphene and it really doesn’t belong there. It’s not like the diethylphalate, it’s a natural component of essential oils, but it’s not a natural component of bergamot oil and so I consider this oil adulterated with camphene. So who cares? Why do we care about whether 1.3% diethylphalate, give me a break, is that really going to hurt anybody? So the point of this is if you bought a used car, is it a problem if it has transmission trouble? Audience: Yes, of course. Kevin: If they tell you it has transmission trouble, is it a problem? Audience: Yes, would I buy it? Kevin: I look at a car and they say, “By the way it has transmission problems,” and it is going to cost $800 to fix the transmission I say, “Well give me a good price on it and I will buy it.” That’s not a problem is it? But if they sell me a used car that has a transmission problem and they don’t tell me about it, I would consider that a problem. So there is nothing wrong with selling a fragrance oil that just smells nice and it is at a reasonable cost and you like it and everybody is happy. There is nothing wrong with selling a blend of essential oils. You can blend geranium oil and lavender oil and sell it as a blend and that’s not a problem. It’s nothing wrong in selling a fragrance oil diluted with a solvent as long as they tell you about it. There is nothing wrong with a synthetic version of a natural scent. The only problem comes when you label it as something other than what it is. So you can represent any of these as fragrances extracted from, but when you say it’s extracted from a specific plant, from a specific location, by a specific method, those things all ought to be correct when you buy an essential oil. So how do you protect yourself? Wholesalers need to test samples of oils that they are considering buying. When Essential Depot is considering buying a batch of lavender oil, they first send me a sample that I can test. I can then tell them is this likely to be a genuine sample and if so then they can order the large batch. It shouldn’t end there, they should then also test the large batch because the supplier could have sent a good sample and then bait and switch sent them a large shipment of something that was different then the sample upon which the purchase was based. Something Essential Depot has started doing is they are batch testing all of their essential oils and then they are posting the analytical report to the web site, so when you are considering buying an oil, you can go and look at my analysis of that oil, you can compare it to the information in Tiseran, which is an affordable book and then there is truth in advertising then. This is what the oil contains and you can decide whether that oil is one that you want to include in your product. So I’m speeding through this, I want to leave time for questions but literally if I’m not in my car at 9:30, I’m going to be very nervous driving down my way to get to the airport. So I will field questions for 15 minutes and then I‘ve got to run. Question: Did you believe in ghosts? Kevin: I do now. I was napping in my room last night and I was awakened by this sound, like a crinkling sound, and I looked over and there was stuff coming under the door. I have always heard of ectoplasm, that ghosts give off. I have never actually seen it before, I can tell you it is crinkly and clear and transparent and it was just shooting under my door and I quickly went to the door and I opened it up and there was nobody there. It was really creepy. Question: I heard that oils come from plants but then I heard you can produce synthetic essential oil. Is there a health wise concern with the synthetic version versus the real version? Kevin: So a fragrance oil could be synthetic or natural. Do I consider fragrance oils dangerous, I do not, but there are people that do and they deserve, if they don’t want an artificial scent in their product, they deserve to be able to buy a natural scent without being lied to. I wouldn’t hesitate, if you just mix 50/50 linalool and lynalyl acetate, it’s going to smell like lavender. It’s going to be missing some of the nuances that come from the minor components, but it’s not going to smell bad and I wouldn’t consider it dangerous, but I respect somebody that would consider it dangerous and doesn’t want to buy a synthetic version. Question: I know Essential Depot doesn’t sell the lavender 4042, which holds up well in itself, I mean are any of them natural that are on the market? Kevin: Well even lavender 40/42, that’s natural, it’s a blend, so there is a whole range of lavender oils, we saw 42 and they’re all scattered all across the map. So somebody that wants to make a 40/42 will blend lavenders from different places in order to get that proportion of linalool to lynalyl acetate. So you have to ask Derek that, that’s none of my business. Question: So a mixture like real, would it have health benefits because some people don’t use it for the fragrance, they use it for therapeutic? Kevin: So if you’re an aroma therapist and you have a world view in which aromatherapy depends on all these things, you’re not going to want a synthetic version, you’re going to want all the things that you want in it and while I might not share your belief, I defend your right to buy something that is correctly labeled. If you want to ask about aromatherapy, you need to ask an aroma therapist, which I am not. Bonnie: But you are saying that 40/42 Lavender is natural? Kevin: I’m not saying it is but it can be. One could make it synthetically, one could make it by blending different lavender oils. Bonnie: Can you tell? Kevin: As you’ve seen, it is kind of difficult because there are gray areas. Could an ingenious person fool me, probably so? Catherine: Why is it called 40/42? Kevin: It’s the percentages of linalool and lynalyl acetate, so it’s an attempt. When you buy a Coke, the Coke is the same every time you buy it. You never open a Coke and you say this one’s different than the last Coke. So 40/42 is an attempt to make a standardized lavender oil rather than the scatter shot we see from the natural population. Question: Are Essential Depot fragrance oils a derivative of the essential oils? Kevin: I’m going to defer that to Derek or Susan, because we aren’t doing any testing on their fragrance oils. All of our testing is on the essential oils. Phyllis: If you wanted to make your own essential oils, like distilling them, what would be the tougher one, I know you haven’t made them all yourself, but one of those that could be harder to distill or something like that? Kevin: I think if you picked something common like lavender or geranium and you can buy a still for, it’s going to cost you several hundred dollars, and it’s only going to make a little bit of oil at a shot. So you’re definitely not going to want to go into production to make lavender oil for your soap business. If you want the experience of doing that then a couple hundred dollars maybe up to a thousand dollars for a nice still, and there are a lots of plant materials that you can distill. At our school this semester, we are doing to be distilling hops, because the professor is interested in hops and so we’re going to be doing that. The principle of it isn’t hard, and I could build a still for $20 that would distill an essential oil, but you know if you buy a nice distill, it’s going to be a nicer experience for you. Susan: Just out of curiosity, we see so many different essential oils but then there are some things noticeably missing like for example why don’t we have an apple essential oil or something like that? I mean is there some reason why some plants just don’t have that? Kevin: That’s a good question. The question is why we get some essential oils and not others. Why do some plants that clearly have an aromatic character to them not produce an essential oil? I don’t know the answer to that. I will have to think about that. If you think about apple, you would be distilling, the skin of the apple probably to get that apple scent, not the leaves. Bonnie: I think they just want oil based scent, maybe water based. Kevin: That could be. They are still all volatile. It should be possible to distill it. Maybe the compounds that are in there are not stable or something. That’s a good question though. So you can get a synthetic apple fragrance oil, but not an apple essential oil. That’s a very good question. Kevin: Okay, you’ve been very kind and left me with a five minute period. Thank you.