EN
The variation in the content and composition of essential oils of Bidens tripartita L. grown in Lithuania has been studied using supercritical CO₂ extraction followed by GC–MS. Extraction of essential oils was performed at two different pressures (9.1 and 15.1 MPa). Plant material has been harvested at different phenological stages (from June to September). A total of 26 different compounds were identified in the essential oils. The highest content and diversity of compounds was determined during the full-flowering stage. Identified substances were mainly monoterpene hydrocarbons and sesquiterpene hydrocarbons. The main components were α-pinene, ρ-cymene, trans-β-ocimene, and β-elemene. Chemometric analysis, including principal component and hierarchical cluster analyses, showed the dependence of the essential oils qualitative as well as quantitative composition on the phenological stage the plant was collected at. It also revealed that there was no correlation between age of the plant and quantity of the identified compounds.