In the master's thesis, we studied the composition of hydrolates of selected species of rose (Rosa sp.) and lavender (Lavandula sp.), which are available on the Slovenian market. Hydrolates are aqueous solutions of many volatile components, obtained as products of steam distillation of herbal drugs. Compared to essential oils, they are less represented on the market and much less researched.
As part of our research work, we obtained 15 samples of rose hydrolate of three rose species and 21 samples of lavender hydrolate of two lavender species from different manufacturers. We analyzed the chemical composition of hydrolates and their hexane extracts using the method of gas chromatography coupled with mass spectrometry (GC-MS). With the help of solutions of standards with known concentration, we determined concentrations for the most frequently represented compounds in hydrolates and the total content of volatile components in the samples. We compared the results of our research with the available literature.
The majority of the hydrolates was represented by water, while terpene alcohols dominated the organic components. The compounds phenethyl alcohol, geraniol, citronellol and nerol dominated in rose hydrolates, while linalool, eugenol, α-terpineol and terpinen-4-ol dominated in lavender hydrolates. More components were detected in the lavender hydrolates than in the rose hydrolates, and in both, fewer compounds were present in the extracts compared to the hydrolates. The remaining dry mass after drying was less than or equal to 1 % in the case of all samples, which also indicates the appropriate quality of the samples. The differences between the hydrolates were noticeable both in the number of components as well as in the chemical composition and added compounds listed among the ingredients of the INCI list.
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