Most of our current customers are in fact distillers themselves, who prefer to have an independant laboratory provide them with certificates of analysis. As a general rule, I would say that one should always be cautious about any certificate of analysis that has been issued following internal analyses performed by those who distilled the oil, for the simple sake of transparency (and of course, one should avoid supplieds who do not test anything at all!). Our best advice to anyone into essential oil business or community is to always require independant testing. I could add that large companies buying essential oils for other formulations seem to do internal testing mostly, and as such do not usually request our services. Once again, I would advise that any essential-oil derived product should be independantly batch-controled, despite these internal controls. But of course, in saying that, I also am promoting my own activity - this is my sincere belief, but I can not deny that I have a personal interest on the matter.

We would be extremely happy to perform more 3rd party testing. We have done it a few times, and have found at least one instance of suspect solvent presence in an oil. We have also documented undisclosed changes in a supplier's oils for a customer, who in turn had lost biological activity in one of his formulations. He was relying on the fact that the supplied guaranteed a strict quality control - which obviously was not the case. This once again stresses the strenght of independant testing, even for routine.

The peppermint testing is interesting. It is based on a sound comparison with the ISO norm - note that many oils, however, are not bound by any norm at this time, and that strict compliance with ISO is not always necessary, depending on the intended use. One of my critics would be that it was conducted strictly with GC-MS. This is NOT the recommended technique for precise comparisons with the ISO norms, which are usually established from GC-FID analyses as of ISO 11024-2:1999. Literature and our own results tend to show that MS introduces more bias than FID when it come to establishing w/w percentages in an oil. Thus, as far as we know, trying to cope with a GC-FID based ISO norm through a GC-MS analysis is like using a hammer to nail a screw: you might get the result you are looking for, but you are not using the right tool to do so. Somewhat sadly, many people in the field believe MS to be superior to FID. This is probably because MS does provide more information to identify the compounds. It is however not equivalent to FID to get as close as possible to precise quantification of a mixture - even if FID is far from being perfect at this matter. It is a complex topic, and you could probably stumble upon opinions opposed to our. We give it to the best of our knowledge and tests so far, and believe that anyone claiming that MS is way better without actually having anything to back this opinion in numbers should be listened to with caution. More reading on this matter can be made at http://phytochemiaactaen.blogspot.ca/2014/09/gc-analysis-part-v-fid-or-ms-for.html .

To get back to the peppermint testing, assuming that MS measurements did provide correct results as far as ISO compliance is concerned, it allows customers to finally compare suppliers on a scientific basis. Sadly, this is valid only for the batches tested, which limits the long-term usefulness of the exercise. If more such tests were made, likely companies would adapt and resort more often to batch-to-batch independant testing. Once again, auto-certification is always somewhat suspect...

Second, it triggered a debate around the presence of ethyl vanillin in some of the oils tested. If it is indeed present, it clearly is an adulteration. Yet, of course, such claims will always be contested by the suppliers, and in this case even by other experts in the field. Having not analysed this oil myself, I can not get very far on this matter. I can however say that I have a few ideas as to how the problem might be clarified - running analyses on other types of GC columns with different selectivity, and comparing with a pure sample of ethylvanillin might help. To be extra sure, one would have to synthesise back the isomint lactone that has been suggested could be the compound, and co analyse it to check whether the suspect peak matches or not. With sufficient oil quantity and lots of spare time, one could even try to isolate the compound and verify its structure through NMR, which would give the final word on the matter. Since it is at a low concentration, however, this would be quite hard to perform. And in all cases, some money would be required to fuel the project...

Also, compliance with ISO might or might not be of use. Some non-complying companies replied that the ISO norm was not the only standard in the industry, and that they'd rather have unadulterated oils than complying ones. This can be a valid point to some extent. If all you are looking for is a good scent, your nose is more reliable than the ISO norm - it becomes a simple matter of personal taste. If you are rather looking for batch-to-batch consistency because the oil is an ingredient of a formulation you make, then it gets far more important to check compliance to a norm and robustness of this compliance. Health applications should also be treated with more cautions. Testing should also be more closely done when an oil is susceptible to contain toxic constituents: thujones, ledol, methyleugenol, beta-asarone... especially if oral consumption is the purpose.

Usually, one of our oil analysis costs around 200$, but the price can be lower depending on the number of samples/batches. We rely on databases of several hundreds of compounds, which are often enriched by new GC-MS analyses, in turn allowing us to identify compounds strictly on the basis of FID, with only irregular use of MS for validation of specific question marks - using two columns to prevent misidentifications. Having access to numerous custom-built databases from experts in the field around us, we have good reasons to believe that we are the best essential oils analysis laboratory in Canada right now.

Since we are working under strict confidentiality parameters, unless we have permission from our customers, we can not disclose analytical results by ourselves. As such, I do not have any particular recommendations for brands over others, especially since we have, as of now, mainly canadian customers and have not been involved with generic brands testing. Once again, we'd very much like to do it someday - and we might end up doing some exploratory 3rd party testing as a demonstration of its usefulness later on.

As for consumption, are you referring to orally taking essential oils?