## 1 Introduction
The widely used SLE technique is versatile and relatively simple. MAE uses more drastic conditions than the widely used SLE method, which in turn is relatively time-consuming. However, extracts from HD, SLE, and MAE can be stored at low temperatures for a long time and analysed as many times as necessary without quality changes. SPME requires sample preparation indirectly before gas chromatography (GC) analysis. Thus, it does not allow for the extract to be stored. However, it should not be forgotten, that the SPME technique also has many important advantages, such as simplicity, sensitivity, and a remarkably short extraction time. This technique is commonly used to isolate VOCs for qualitative purposes, such as monitoring the changes in volatile substances during storage, volatile substances profile, or metabolomic purposes [19; 20; 21; 22; 23]. Liverworts are widespread throughout the world, but most often in the tropics. Liverworts are the ancestors of all land plants and abundantly produce specialized metabolites, including monoterenes, sesquiterpenes, monoterpenoids, sesquiterpenoids, and aromatic compounds, many of which exhibit notable biological activities, such as the inhibitory effects on allergic contact dermatitis, cytotoxicity, antibacterial, and antifungal activity, anti-insect activity, and antioxidant properties [24; 25; 26]. On the basis of these statements, it can be concluded that it is very important to develop the best method for the extraction of these compounds from plants. In their natural environment, you can find deciduous and thalli liverworts. A leafy liverwort typically has leaves of two sizes, arranged in three rows along the stem. The larger leaves (called lateral leaves) grow in two rows, along opposite sides of the stem. Most leafy liverworts are prostrate plants and grow along some substrate (e.g., soil, bark, leaves, or rock). The coplanar arrangement of the lateral leaves gives leafy liverworts a \"flat\" look that is rare in mosses. Thallose liverworts, which are branching and ribbon-shaped, grow commonly in moist soil or damp rocks, whereas leafy liverworts are found in similar habitats as well as tree trunks in damp woods. The thallus (body) of thallose liverworts resembles a lobed liver, hence, the common name liverwort ('liver plant'). Plants are not economically important to humans, but provide food for animals, facilitate the decay of logs, and aid in the disintegration of rocks by their ability to retain moisture. Most liverworts contain oil bodies, which are intracellular organelles surrounded by a single membrane in which a wide variety of specialized metabolites are synthesized and accumulated, such as terpenes, terpenoids, sesquiterpenes, sesquiterpenoids, and aromatics [15; 16; 17; 18; 19; 20]. The presence of nitrogen, sulfur, or both nitrogen and sulfur compounds in liverworts is very rare. The most characteristic chemical phenomenon of liverworts is that most sesqui- and diterpenoids are enantiomers of those found in higher plants [6]. Furthermore, the determination of the composition of secondary metabolites that fall under the scope of chemotaxonomy can be one of the methods to help identify taxonomically difficult species [27]. In this study, various techniques were used to extract volatile components from _Calypogeia azurea_. The purpose of the research is to compare the most frequently used methods of extracting volatile organic compounds from liverwort cells. The results allow the provision of information on which extraction technique is most appropriate for this species of liverwort. The collected information may be useful in further research into other liverworts from the Calypogeia genus.