Hi, my name is Alexandra and I am a French undergraduate student in the second year of a bachelor degree in chemistry. I am specialized in analysis and would like to work in green chemistry.

I am doing my internship at the University of Ottawa and work on the chemical composition of hydrosols. I hope to learn more about the functioning of the GC-MS but also how it is used to analyse samples. I am very excited about this opportunity that will allow me to develop my experience in analytical chemistry !

I had the opportunity to work on vanilla and more precisely on the components of a vanilla non darkening fragrance oil in order to compare the present chemicals whith the ones in the essential oil.

The analytical method used is the GC-MS, gaz chromatography - mass spectrometry, in order to identify and quantify the components of fragrance oils. The samples were made with 1µL of the fragrance oil diluted into 2 mL of acetate nitrile, a nonpolar solvent, in order to have a concentration of 0.5mg/mL.

The experimental conditions of the analysis are:

• Oven temperature: 40°C - 300°C
• Rate: 15°C/min
• Inlet temperature: 250°C
• Column flow: 1,3 mL/min

The SMPE method is used to analyze the headspace thanks to a fiber that catches molecules in the air. Those molecules are identified by GC-MS with the same parameters as before except for the temperature of the inlet, which has been lowered to 200°C.

We aim to analyze if the same chemical components are present in the essential oil and in the fragrance oil. It will allow us to find what non natural compounds are present in the fragrance oil and were added by the industry.

Fragrance oils are blended synthetic aroma compounds or natural essential oils that are diluted with a carrier like propylene glycol, vegetable oil, or mineral oil.

This vanilla non darkening fragrance oil contains 24 chemicals, some of them have high temperature such as oxybenzone and DEHA.

As the chromatogram shows, several components are present in the vanilla fragrance oil and some synthetic molecules are present in high quantities. We will focus on the seven main components represented on the chromatogram and analyze their role in the formula. We are wondering if those molecules are used to their smell or if they have other functions.

Vanillin is a member of the phenolic aldehydes that has a role as a plant metabolite, an anti-inflammatory agent and a flavoring agent. This organic compound is the primary component of the extract of the vanilla bean, but synthetic vanillin is now used more often.

Ethyl vanillin which has the role of antioxidants and flavoring agent, is a member of the class of benzaldehydes that is vanillin. However, the ethyl vanillin is more expensive, but has a stronger note. It differs from vanillin by having an ethoxy group instead of a methoxy group.

The nonalactone is a chemical substance used in various fields. It can be used in candle formulation to add a pleasant aroma. Indeed, this chemical compound offers a sweet and fruity note improving the smell of scented candles.

Hexanedioic acid, bis(2-ethylhexyl) ester also called DEHA is a natural organic compound that helps to improve the flexibility and durability of the fragrance oil, ensuring that it remains stable and consistent over time. Additionally, this additive can also serve as a solvent, helping to dissolve and distribute the fragrance compounds evenly throughout the oil. Overall, its use in fragrance oils helps to enhance their performance and shelf-life.

Diisooctyl adipate, in the same way then DEHA, is a perfect candle additive used to improve the durability of the fragrance oil, guaranteeing a stable formula. It helps to soften the fragrance oil, which can aid in the blending and distribution of fragrance compounds. It has also a slight aromatic smell and is a solvent used in order to dissolve the ingredients in the formula, for example in the cosmetic product. 

Oxybenzone is an organic compound belonging to the class of benzophenones that plays the role of additives in scented candles. It is sometimes added to help stabilize the color of the wax and extend the burn time of the candle. Additionally, it can help enhance the scent of the candle by helping to diffuse the aromas. However, this product is at the origin of environmental hazards.

Propylene glycol is a carrier and effective solvent for dissolving and stabilizing the ingredients of a formula. It can help stabilize the formula by preventing ingredient separation and extending the life of the product. It is also used to fix the odor of the candle.

On both fragrance and essential oils of vanilla, the vanillin represents only a small quantity of the total oil. The only other component shared is the D-Limonene but it has a very small area % which is 0.53% for the essential oil and 0.07% for the fragrance oil.

According to the fragrance oil website, the vanilla non darkening fragrance oil is composed of 1.116 to 4.716% of vanillin and between 0.744 and 3.144% of ethyl vanillin. Thanks to the GC-MS analysis it is possible to ascertain the real percentage of those molecules in order to compare the theory with the practical. A percentage of 4.9% of vanillin was found which is close but a little higher than the value indicated by the seller. However, the amount of ethyl vanillin is perfectly in line with the theoretical area %.

A SPME analysis was done in order to analyze the components present in the head space of the fragrance oil. As we can see here, the SMPE has shown that only one component is visible. It is the nonalactone, responsible for a sweet and fruity smell and which is the more volatile compound.

An experiment to analyze the components of a burning candle containing the fragrance oil was made but has shown that there are non chemicals in the head space. However, it allowed us to determine that some solid molecule is present and were obstructing the syringe.

Thus, the fragrance oil and the essential oil of the same product do not always have the same chemical components and this particular vanilla non darkening fragrance oil was made thanks to synthetic compounds.

The fragrance is composed of vanillin, ethyl vanillin and nonalactone that are used in order to have a pleasant scent so that the lit candle helps create a relaxing atmosphere.

A lot of additives are present in this fragrance oil such as the DEHA and the diisooctyl adipate that are the main components. They are added to the formula in order to expand the life expectancy of the candle, stabilize the color and have a stable mixing over time.

Finally, a huge amount of ester is contained in that oil, helping the blending of chemicals. They also contribute to the scent profile by providing fruity, floral, and sweet notes and have often a good stability and longevity in scent compositions