The rose, Rosa, is the flower of the rose bush, a member of the Rosaceae family. One of the world’s most popular flowers, it has been celebrated by poets, writers and painters since Antiquity.

Its main characteristic is the multiplication of its petals, grouped in layers to form a perfect symmetry. Their color palette is vast, ranging from intense red to pure white, through shades of pink, yellow, orange and even violet. Some varieties are also known for their intoxicating fragrance. Roses are also used in the perfume, cosmetics and essential oil industries for their scent and various benefits.

Rose

My name is Eloïse Agnel and I am a 2nd year undergraduate student in chemistry in Montpellier, France. I am doing a three-month internship at the University of Ottawa and hoping  to gain more experience in the lab. During my internship, I will gain an understanding of how GC-MS allows compounds to be analyzed in various samples. We will use this technique to analyze hydrosols and essential oils to further discover the different odorous components. I have always been passionate about the cosmetics and perfumery industry, so this internship will be very enriching for my professional project.
 

Eloïse

Analyzing method for fragrance oils

  • Sample preparation​
    1 µL of each  fragrance oil is  diluted in 2 mL of Acetate Nitril (non polar solvant) to have a concentration of 0,5 mg/mL.
  • GC/MS parameters​
    Oven Temperature: 40°C - 300°C
    Rate: 15°C/min​
    Inlet Temperature: 250°C​
    Column Flow:1,3 mL/min
rose

"Rose bouquet" fragrance oil

First, we analyzed the “rose bouquet” fragrance, which smells like a delicious bouquet of fresh, fragrant roses and we obtain 18 compounds. 

Phenyl ethyl alcohol is the main product with a retention time of 7,837 and a surface area of 26,02%. It is a primary alcohol found in extracts of rose, carnation, hyacinth, Aleppo pine, orange blossom, ylang-ylang, geranium and neroli. Its structure enables it to have aromatic and chemical properties notably used in the perfume industry. It is also an anti-microbial agent, antiseptic and disinfectant, and is widely used for its preservative properties.

The second compound present in large quantities is solketal. It is used in the perfume and cosmetics industry for its odorant properties and perfume-fixing capacities. 

Finally, the third compound present in large quantities is citronellol with a retention time of 8,977 and an area 10,94%. It is a natural acyclic monoterpenoid. Both enantiomers occur in nature. (+)-Citronellol, found in citronella oils, is the most common isomer. (-)-Citronellol is widespread, but particularly abundant in rose.

Then we have geraniol in small quantities, with an area of 3,41%. It’s a monoterpene and makes up a major part of rose and palmarosa oils.  

We also have the hexylene glyccol, famous for its excellent solvency among a wide variety of materials and is popular due to its ability to improve the texture. 

Finally, isopropyl myristate, used in cosmetics and pharmaceuticals to facilitate penetration of products into the skin when emulsified with water. 

rose bouquet

"Rose garden" fragrance oil

Next, we analyzed the “rose garden” fragrance oil and we get 15 compounds.

As in our previous analyses, the main compound is phenyl ethyl alcohol with a retention time of 8,059 and a surface area of 37,85%.

The second compound is citronellol, also found in the “rose bouquet” fragrance oil, with a retention time of 9,181 and an area of 17,17%.

Then we have geraniol at 9,417 with an area of 4,63%.

Then, in smaller quantities, we have 4-tert-butylcylcohexyl acetate used in various cosmetic products as a perfuming agent with the aim of adding odor or taste, creating a pleasant smell or masking a bad odor.

In addition, we have benzyl alcohol, of natural, plant-based origin. It is naturally present in many plants, including essential oils of jasmine, ylang-ylang, rose…

rose garden

Conclusion

Following our analyses, we can observe that we regularly obtain the same compounds such as geraniol, citronellol, limonene, phenyl ethyl acetate and diphenyl ether, in different proportions.

However, the product we systematically obtain is phenyl ethyl alcohol. This is always the majority compound, and we can conclude that it is this molecule that is largely responsible for the characteristic scent of roses. 

The many compounds added to obtain the desired fragrance, but which also provide certain properties, are mainly of natural origin.