Essential Oil GC/MS Testing for Purity

Last Updated on November 11, 2022 by Brenda

Today there is an abundance of 100% pure essential oils to chose from. But are you aware that you are buying your essential oils GC/MS tested for purity to know they are unadulterated and not fake with added ingredients or watered down with other chemicals? GC/MS means Gas Chromatography/Mass Spectrometry. Those seem like mysterious words and I will demystify them for you here.

Many times, you are persuaded to sign up with an essential oil company to make money selling their oils or getting their oils for free. This is called MLM (Multi-Level Marketing) to be discussed in another article here.

You can now use essential oils in recipes, use in diffusers for aromatherapy and more.

1. GC/MS Testing for Purity

Buyers of essential oils rely on oils that are not GMO (Genetically Modified Organism) and are GMP (Good Manufacturing Practice) certified using sustainable farming. The reputable oils companies use these best practices using no fertilizers and are USDA (United States Department of Agriculture) certified to be organic.

The GC/MS testing analyzes individual molecules of each plant’s oils so that companies selling the oils will have the best quality essential oils in the marketplace.

Mass-Spectrometry is a combination of both the processes of GC and MS. Its purpose is to separate the chemical elements of a certain compounds and identify the molecular level components.

2. Trust and Safety

The plant oils are tested by a third-party laboratory using GC/MS, a method of separating the volatile compounds in essential oils into individual components. The Gas Chromatography uses a computer that produces a linear graph that charts individual components for purity. The best essential oil companies are concerned with our health and safety using their products, and I value this as will you.

Purity is everything when it comes to buying and using essential oils.

3. GC/MS Testing is Not About Soil

Only the volatile plant oils, the essence of the plant that evaporate quickly, are tested. The soil the plants are grown in is not tested. GC/MS does not test whether the plants were grown in soil of high-quality elements for nutrition for the plants.

Organic farming produces higher quality essential oils for the best in therapeutic benefits. Organic oils are sold by the best essential oil companies.

The little Basil plant looks healthy in its organic soil pictured at the bottom.

Plant Therapy®, a highly regarded essential oil company, makes a wonderful 6-bottle set of organic oils that are inexpensive for both beginners and seasoned users of essential oils.

4. Qualitative and Measurable Analysis

You might be wondering, What’s the difference concerning qualitive and measurable, sometimes called qualitative testing? This test relates to measuring by quality or kind rather than quantity and about how good the oil is.

Therefore, qualitative tells us what individual components are in the oil and the measured analysis or quantifiable test that gives information for how much is present of each component in the oil that is assessable.

Qualitative and Measurable Analysis

With the expert analysis, the oil and country of origin is verified. It’s important that the country is verified since the quality between countries can differ along with the price.

5. Our Senses Evaluate Oils

Our Senses Evaluate Oils

The senses used for evaluating essential oils are mainly our nose and eyes. The viscosity or thickness of the oil is important along with the color, smell, and transparency of the oil known as clarity or how clear the oil is.

The young lady pictured is carefully looking at a young bird admiring a flower in her other hand.

Rose Otto (Rosa damascene), for instance, gets hard or congeals at low temperatures of about 60-degrees F. due to the natural waxes it has. It should still be moveable to let you know it’s a good brand oil.

Rose Otto 10% 5 mL diluted is inexpensive and the non-diluted Rose Otto essential oil 2.5 mL is about $100.

If Rose Otto moves at a low temperature, it has probably been altered with some type of additive. You want it to congeal at 60-degrees F.

When you buy Geranium (Pelargonium graveolens) you will want to buy from countries such as Egypt, Africa, and China listed on the bottle label.

Note the difference in colors. Chinese Rose Otto essential oil is green while Egyptian is the beautiful golden color that it should be.

When the oil is pictured in the amber colored glass bottles online, you cannot see the color.

6. The Smell Test

The nose knows!

Smell Test Essential Oils

Sometimes, as with Lavender (Lavandula), you can actually smell ingredients other than pure Lavender in the bottle.

Always buy your essential oils—even Lavender from well-established trusted companies with a good reputation. Trustworthy and highly regarded companies are more liable to adhere to the USA FDA (Food and Drug Administration standards.

These companies will tell you where they source their plants, testing procedures, and how the oils are distilled.

The best Lavender essential oils are from Europe with a minor amount from the Pacific Northwest. Steam distillation is the distillation process that’s best.

The price will help you determine the oil’s true purity. Lavender can cost up to $45 for pure oil. If its very cheap, it’s probably not real.

7. Gas-Chromatography Testing

Gas-Chromatography (G/C) can identify trace elements in plants that were formerly thought to have fragmented or disappeared beyond detection or identifying. Mass-Spectrometry (M/S) detects the most miniscule amounts of substances.

Gas-Chromatography Essential Oil Testing

When doing a G/C test with essential oils, a small sample of the oils is inserted into a vial that contains a thin coiled silica tube known as a capillary column. The column might be 3937-inches (100-meters) long and coated with a chemical for detecting different chemicals at different temperatures.

The column goes into a temperature-regulated oven that is programmed to increase the temperature over time very precisely.

The oil vaporizes instantly and an inactive gas usually hydrogen or helium moves the vapor to a Flame Ionization Detector (FID) located at the end of the column.

Schematic of an FID for Gas-Chromatography

This is a is a scientific instrument that measures analyte in a gas stream. It is frequently used as a detector in Gas-Chromatography.

8. Identifying Essential Oil Components

The FID, shown above, responds with the amount of the vaporized components in the oil. The information transfers to a computer that shows peaks printed out on computer paper.

Identifying Essential Oil Components

The height of each peak matches the level of the element in the oil being tested. Each component is any flavored oil that can be identified and then compared to the profile of the specific essential oil for determining its purity.

Contaminants, additives, and impurities can be recognized and identified with this type of testing that usually needs to be done by an expert organic analytical chemist.

Climate and soil types where the plants were grown will produce innate dissimilarities in plants of the same species.

GC-MS Analysis

Gas-Chromatography/Mass-Spectrometry accuracy is reliable, dependable, consistent, and trustworthy.

Final Thoughts

The chemistry to do GC/MS is complicated to understand. Just know that the best essential oil companies do this testing for you to have the best unadulterated 100% pure essential oils to use in diffusers, use on your body with carrier oils for a healthy holistic massage, and are safe to use with pets. Be well and be happy using pure essential oils.


Welcome to my blog! I am Brenda Star and I am a true believer that Nature is fascinating and enchanting. The history of herbs and their uses are captivating. I have always wondered how did the ancient people know—how did they come to understand what a plant would do. They did not experiment in a lab because those technologies did not exist. That wisdom will always be a mystery to me. More about me...