My name is Joey Li, and I am volunteering in the John L. Holmes Mass Spectrometry Facility in summer of 2024. I just finished my first year of Biomedical Science at the University of Ottawa, and I am going into my second year in September 2024. I volunteered in this lab with the goal of gaining more experience in the field of chemistry and getting an insight into research. My ultimate goal is to get admitted to medical school, where I wish to specialize in rheumatology so I can help improve the lives of those unfortunate enough to be diagnosed with autoimmune conditions. Volunteering in this lab not only allowed me to apply the skills I have learned in my first-year chemistry classes, but also allowed me to explore the diverse world of mass spectrometry and its vast range of applications in science research. Throughout the course of the summer, I learned how to prepare and analyze samples, identify and quantify different compounds in the samples using both the GC-MS and LC-MS, and the fascinating ways in which mass spectrometry instrumentation works

Korean mint is known scientifically as Agastache rugosa and is an herb belonging to the mint family (Lamiaceae). As the name suggests, it is native to countries in East Asia, including Korea, China, and Japan. Thanks to the aromatic leaves of the plant, it is often used in various culinary applications, such as for flavouring beverages, oils, and vinegars. Korean mint typically grows to a height of 1 to 1.5 meters. As with other plants of the mint family, Korean mint has square stems. Leaves are lance-shaped, and flowers are tubular and usually purple or blue. In terms of growing conditions, Korean mint prefers lots of sun and well-drained soil. The plant is very easy to grow and is fairly resistant to weather conditions. The leaves of the plant have a strong aroma, similar to that of licorice. The flavour of the plant is sweet with a hint of spiciness. These characteristics make it a favoured ingredient in teas and culinary dishes. Korean mint has been used in traditional medicine for centuries. It is believed to have a variety of health benefits, including but not limited to aiding digestion, relieving nausea, and relieving fever. In Chinese medicine, Korean mint is a common ingredient in formulas designed to treat colds and gastrointestinal issues. Korean mint is highly favoured by pollinators like bees and butterflies, making it a popular plant for gardeners wishing to expand their garden.

Hyssop is known scientifically as Hyssopus officinalis and is a perennial herb belonging to the mint family (Lamiaceae). It is native to southern Europe, the Middle East, and some parts of Asia. Hyssop has been used for centuries in traditional medicine, culinary applications, and even religious rituals. Hyssop typically grows to a height of between 30 and 60 centimetres. Stems are woody at the base, and are square as with other plants of the mint family. Leaves are dark green and narrow with a very strong aroma. Flowers are small, tubular, and typically blue or purple. In some regions, varieties with white and pink flowers also exist. Hyssop has a strong minty scent, only slightly more bitter. The same thing can be said for its flavour. From a culinary perspective, hyssop leaves are used sparingly due to their intense flavour. Hyssop prefers lots of sun and well-drained soil, though it can thrive in poor soils and is quite drought tolerant. These characteristics make it very easy to grow. Hyssop has quite a history in traditional medicine, with traces of its use from as early as 1600 BCE. It has been used as a remedy for respiratory conditions due to its expectorant properties, which allows it to help clear mucus from a person’s airways. Hyssop tea is consumed to relieve digestive issues, and the herb also has antiseptic and anti-inflammatory properties. From a religious perspective, hyssop has significant religious symbolism in Judeo-Christian traditions. It is mentioned in the Bible, where it was used in purification rituals. In ancient times, the herb was used for cleansing and purification purposes. Thanks to its attractive flowers and strong aroma, hyssop is a favourite among pollinators. This makes it a great plant for those wishing to enhance biodiversity in their gardens

The objective of this study is to examine the chemical compounds found in the hydrosols of each plant using the GC-MS. Both the Korean mint and hyssop used in this study were provided by Dr. Sharon Barden, who grew the plants in her garden. The plants were freshly harvested and cleaned prior to using microwave distillation. Since the plants were fresh from Sharon’s garden, they were covered in stinkbugs (Halyomorpha halys) that had to be washed off. Unfortunately, due to the sheer abundance of these bugs on the harvested plants, it was likely that some of them were missed in the cleaning process and died a painful death being cooked alive in the microwave. To create the hydrosol, the plants were put into large glass jars for microwave distillation. The jar was then fitted with a 400mL beaker in the centre, with a 250mL ice cone attached to the lid pointing into the jar. The jar was then placed in the microwave for 7 minutes, during which the volatile compounds in the plant are collected in the 400mL beaker by the ice cone. Once this was done, the contents of the beaker were poured into a bottle for storage. The entire process was completed four times for each plant with a new ice cone each time. In total, a litre of hydrosol was collected for each plant. The hydrosols were put through SPE (solid phase extraction) before running them through the GC-MS. Two samples were prepared for Korean mint, one with 1mL of hydrosol and the other with 5mL. Three samples were prepared for hyssop, one with 1mL of hydrosol, one with 5mL, and one with 10mL. Using the SPE helps to elute the analyte in the hydrosol with a nonpolar solvent, as the water in the hydrosol is polar and can damage the GC. Each sample was run once in the GC, with each run set to begin at a temperature of 40°C and end at a temperature of 320°C. The temperature in the GC was set to increase in increments of 20°C per minute.

The Korean mint hydrosol contained only one compound, which was estragole. Despite this, it was very dilute at only 0.08mg/L. Estragole is colourless. It is a flavouring agent and insect attractant, which makes sense given the culinary and pollinator attracting applications of Korean mint. In high concentrations, estragole can be genotoxic and carcinogenic. Estragole has a licorice odour and sweet taste, and is insoluble in water.

The GC-MS was able to identify a lot more molecules in the hyssop hydrosol. However, once again, the molecules identified were extremely dilute. Starting on the left side of the chromatogram, 3-carene has a concentration of 0.0050 mg/L. Linalool is found at the lowest concentration in this sample, at 0.0042 mg/L. Pinocamphone is slightly more concentrated, at 0.0058 mg/L. Isopinocamphone was the most concentrated, with a concentration of 0.47 mg/L. Myrtenol was identified as the peak that comes after isopinocamphone, with a concentration of 0.026 mg/L. 3-carene is a monoterpene with a sweet odour. It has anti-inflammatory, antimicrobial, and anxiolytic effects. Linalool is terpene with a citrus/floral like odour resembling that of French lavender plants. It has anti-inflammatory, anticancer, antimicrobial, and neuroprotective effects. Pinocamphone has an herbaceous, camphor-like odour. It shows antimicrobial activity, though large amounts can be neurotoxic and has stimulating effects. Isopinocamphone is a bicyclic monoterpenoid with a cedar aroma. It shares the same effects as pinocamphone and will also be dangerous in high concentrations. Myrtenol is another bicyclic monoterpenoid with a woody scent. It has anti-inflammatory, antimicrobial, analgesic, anxiolytic, and antioxidant effects

While Korean mint and hyssop share a strikingly similar appearance, the two plants are completely different in their chemical composition. Both plants were sourced locally from Sharon’s garden. Using the GC-MS, only one molecule was identified in the Korean mint hydrosol, whereas five were identified in the hyssop hydrosol. In the Korean mint hydrosol, the only identified compound was estragole, which gives the plant its licorice odour. In contrast, the hyssop hydrosol contained five compounds, with isopinocamphone being the most abundant. Isopinocamphone contributes a woody scent to the overall aroma of hyssop.