Gas Chromatography and Mass Spectrometry (GC-MS) is a quantitative analytical test performed on Essential Oils to scientifically prove authenticity, plant DNA and purity in Essential Oils.
It is the gold standard in the lab-testing for essential oils, we only include certified organic, biodynamic and wild harvested essential oils that have undergone GC-MS testing, this absolutely ensures only unadulterated, pure, therapeutic grade, essential oils of the highest possible quality make it into our formulations and your skin. Essential oil are incredible potent, volatile liquids which consist of hundreds of distinct chemical compounds; that require careful consideration along with correct formulation techniques and compliance with EU Cosmetic Regulations following Safety Guidelines set out by the International Fragrance Association. Read more about Dermal Limits for Essential Oil Safety
The Tests Explained
Gas Chromatography // Gas Chromatography, also known as Gas Liquid Chromatography is abbreviated as GC or sometimes GLC. This test measures the constituents contained within a particular essential oil sample by plotting each constituent found within the sample onto a graph. The gas chromatograph machine plots a graph of the results. The x-axis identifies the time that passes between the vaporisation of each constituent. The y-axis shows the percentage concentrations of each constituent within the oil.
Mass Spectrometry // Mass Spectrometry, abbreviated as MS is often used in conjunction with Gas Chromatography as it can aid in determining if a sample contains any adulterants. Each compound, after passing through the gas chromatograph machine, is fed into the mass spectrometer. The Mass Spectrometer ionizes the compounds, sorts each by their mass-to-charge ratio and then measures their molecular weights. The results are then charted.
The data collected by way of the combined GC-MS test analyses the chemical constituents in the essential oils and give the relative percentage of them. This information can be used to compare the specific constituents and their percentages to those of a known sample that possesses reliable purity and is of the optimal quality for the specific botanical (being tested). The results are used in a number of ways:
- Unusual levels of particular constituents in the tested oil can flag that the oil is of inferior quality or has been adulterated.
- Distillers of essential oils often test their oils to compare with previous distillations to cross-reference quality between harvests and distillations.
- If GC-MS results determine that the essential oil contains an unsuitable level of certain constituents, distillers or producers may adulterate the oil so that the oil appears to be of higher quality.
Organoleptic Analysis // Is undertaken to determine aromatic quality of an essential oil. This analysis – a combination of aroma (smell), texture (touch), colour (sight), as well as taste. While taste is not always necessary, it can play an important part of an evaluation for certain essential oils. Colour variation can also be a very important indicator of quality and is also used to detect an older or oxidised essential oil.
Physicochemical Tests // These are physical measurements using specific instruments in the lab checking:
Refractive Index // Of an essential oil is a unique number that designates how the oil responds too and bends light. Essentially, it is a measurement that tests how the speed of light is altered when passing through the oil. An oil’s refractive index can be compared to that of a reliable sample.
Optical Rotation // Is determined by a polarimeter, it means the angle of degrees at which the oil passed through light.
Specific Gravity // A Specific Gravity (SG) is the ratio of weight of liquid to that of an equal volume at the same temperature. This is don by using a density meter.
Viscosity // Viscosity is the how thick or thin the consistency of the essential oil which indicate how easily the essential oils will pour.
The results of GC/MS tests vary slightly between each essential oil, but remain within a certain acceptable range when no adulteration has occurred. So not only must the GC/MS test data be correct for an oil to be assured as pure, but results of these additional tests must also be in compliance.
CONCLUSION // After two years of searching and trialing essential oils from manufactures around the world I have chosen to work only with one supplier. This has caused delays in the launch of my initial product, and Brand, a decision I took because we share the same ethos – quality over price, efficacy over marketing hype, sustainability of the sourcing of the ‘plants’ along with safety and transparency. #slowbeauty.
Until next time
be human be kind be you
- Essential Oil Quality
- Book // Essential Oil Safety: A Guide for Health Care Professionals 2nd Edition by
- IFRA Guidelines –
- Book // The Complete Guide to Aromatherapy Second Edition S. Batteglia (2007) Johnson, Dr. Scott A.. Evidence-Based Essential Oil Therapy: The Ultimate Guide to the Therapeutic and Clinical Application of Essential Oils