Hi, my name is Amina, and I am  21 years old. I'm in my second year of pursuing a Bachelor's degree in Chemical Engineering with a specialization in Analytical Chemistry at the University of Montpellier in France.

Currently, I am undertaking my second-year internship at the University of Ottawa. This choice aligns with my career aspirations in the cosmetics and perfumery industry. The focus of my internship revolves around hydrosols, which complements my academic journey perfectly.

During this internship, I will be conducting GC-MS analyses on these hydrosols, allowing me to deepen my understanding of analytical techniques in this field.
 

Lilacs smell great, but they don't make essential oils like some other flowers do. That's because they don't have many oil glands in their flowers, so there's not much oil. Also, the specific chemicals needed for making lots of essential oil might not be in lilacs. Even if there's a bit of oil, getting a lot of it out is hard. So, perfumers often use different ways, like synthetic fragrances or other natural floral scents, to get the lilac smell into their products. Even with these challenges, people still love the smell of lilacs, and it keeps inspiring new ideas in the perfume world.

We might wonder what's in the lilac fragrance and how manufacturers recreate it synthetically. To analyze the components, I conducted a GC-MS analysis using the same parameters as before. I examined the fragrance from the brand "Canwax," commonly used for candle making.

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

Analyzing method for the headspace​

• SPME​
  Fragrance oils are heated and with the fiber, molecules in the headspace are cathed.
• GC/MS parameters
  Oven Temperature: 40°C - 300°C
  Rate: 15°C/min​
  Inlet Temperature: 200°C​
  Column Flow:1,3 mL/min

After GC-MS analysis, we observed the presence of 25 peaks, indicating 25 different compounds in the lilac fragrance. Mainly, three products stand out, making up 68.339% of the fragrance. So, our focus will be on understanding their role and significance in shaping the fragrance profile.

It's important to note that benzyl benzoate used in perfumes is typically synthetic. Its produced through a chemical reaction between benzoic acid and benzyl alcohol.

Benzyl benzoate acts as an odor fixative. It serves as a scent stabilizer, extending how long the fragrance lasts on the skin and in the air. This fixative function arises from benzyl benzoate's ability to form stable bonds with other volatile compounds present in the fragrance. By doing so, it traps the odor molecules, slowing their evaporation and ensuring a gradual and continuous diffusion of the perfume over time. Thus, it plays a role as a heart or base note. Additionally, it also possesses odorant properties. Besides, it has its own pleasant smell, adding a sweet and delicate touch that blends well with other floral scents, even though it doesn't exactly mimic the lilac flower's scent.

Next, we have Phenylethyl Alcohol, present at 20.25%, which shares similar properties with benzyl benzoate. It also acts as a fixative, extending the fragrance's longevity. It can also be synthesized through various methods.

This compound is found in extracts of rose, orange blossom, ylang-ylang, geranium and neroli. While it doesn't give a lilac scent, it offers a fresh floral fragrance.

α-Terpineol is a terpene alcohol present in various plant essential oils. Belonging to the monoterpenol chemical family, it is widely employed in the perfume industry for its distinct aromatic properties.

It is the most common of four structural isomers, with the others being β-, γ-, and 4-terpineol. α-Terpineol contributes to giving lilac fragrance its floral and sweet character, along with slightly woody and fruity notes. As a key component, it plays an essential role in creating an authentic and recognizable fragrance. Its use in lilac-scented compositions allows for capturing the very essence of this iconic flower.

Of course, there are several other products, but I won't list them individually because they're all there for the same reason: to achieve the scent of lilacs. So, we find for examples products that give the scent of camphor like borneol, and also the flower scent like piperonal.

I also conducted solid phase microextraction (SPME) to identify the products we can smell when using the fragrance. The fragrance was heated to 50°C. I left the SPME in the headspace for 5, 7, 10, and 14 minutes. I decided to keep the results obtained with a 14-minute sampling time because that's when I obtained the best results.

I also made a candle with the fragrance of lilac and analyzed the scents it emits when burning. Initially, the candle was placed in a large jar, but I decided to put it in a beaker because I wasn't getting any peaks. This new method allowed me to work in a smaller space and thus have a better chance of capturing the molecules present in the headspace.