Stinging nettle is a perennial plant with significant biological activity and a long history of application in folk medicine and as food. Its activity is ascribed to its chemical composition. Its leaves contain different classes of compounds including fatty acids. This study deals with the isolation of fatty acids in stinging nettle leaves using a rapid extraction system for solid–liquid extraction (Soxtherm) with petroleum ether as the solvent. The obtained results indicate that the saturated fatty acids are more abundant than unsaturated fatty acids. The most abundant fatty acids are C12 : 0 (20.94%, 348.07 μg g⁻¹), C16 : 0 (18.57%, 309.06 μg g⁻¹), and C18 : 1 (13.16%, 219.44 μg g⁻¹), whereas the fatty acid with the lowest content is C17 : 1 (0.13%, 2.20 μg g⁻¹). Prior to analysis, the method is validated to obtain accurate and precise results. The limit of detection and limit of quantification are 0.012–0.038% and 1.67–7.03%, whereas the precision and accuracy are 83–126% and 1.67–7.03%, respectively. The validation parameters are >0.999, 0.011–0.032%, 0.012–0.038%, 1.67–7.03%, 83–126%, 0.22–5.24%, and 0.38–6.94% for linearity, limit of detection, limit of quantitation, precision, accuracy, inter-day precision, and intra-day precision, respectively, confirming the suitability of this method for fatty acid analysis.

Stinging nettle (SN) is an extraordinary plant from the Urticaceae botanical family. It is well-known and widely used in food and folk medicine to treat different disorders and diseases. This article aimed to study the chemical composition of SN leaves extracts, i.e., polyphenolic compounds and vitamins B and C, because many studies ascribed high biological potency to these compounds and their significance in the human diet. Besides the chemical profile, the thermal properties of the extracts were studied. The results confirmed presence of many polyphenolic compounds and vitamins B and C. It also showed that the chemical profile closely correlated with the applied extraction technique. The thermal analysis showed that analyzed samples were thermally stable up to about 160 °C. Thermal degradation of samples UAE, MAE, and MAC took place in four steps, and sample SE in three steps. Altogether, results confirmed the presence of health-beneficial compounds in stinging nettle leaves and indicated the possible application of its extract in pharmaceutical and food industries as both a medicinal and food additive.

One of the most common techniques for wine analysis is gas chromatography coupled with the flame ionization detector and headspace autosampler (HSS-GC/FID) for the analysis of the volatile compounds in the wine samples. The main goal of this thesis was to develop the method for the analysis of volatiles (methanol, higher alcohols, and esters) in wine samples made of Cabernet Sauvignon and Merlot. Validation parameters were: r² > 0.995; LOD (0.2–1.0 mg/L); CV (2.7–6.3%), and recovery (92–106%). Average contents of the methanol (198.0 mg/L and 150.5 mg/L), higher alcohols (398.5 mg/L and 335.8 mg/L), ethyl acetate (42.0 mg/L and 55.6 mg/L), and acetaldehyde (23.3 mg/L and 16.1 mg/L) were determined for Merlot and Cabernet Sauvignon, respectively. Based on the obtained results, it was concluded that the content of methanol is in direct connection with the type of grape used for preparation of the wine. It was also found that the duration of the maceration directly influenced the content of the methanol and higher alcohols. On the other hand, type of grape appeared not to have influence on the content of ethyl acetate and acetaldehyde in wines. The post hoc Tukey’s HSD test at 95% confidence limit showed significant differences between observed samples. Principal Component Analysis (PCA) was used for assessing the effect of different genotypes and extraction methods on wine samples. Using PCA of observed samples, the possible directions for improving the quality of product can be realized.

Stinging nettle (Urtica dioica L.) is a perennial plant belonging to the Urticaceae family. Several studies have reported the presence of the different classes of chemical compounds, which expressed a beneficial effect on human health. Among them there are elements and minerals that are essential for the proper functioning of organism. Mineral occurrence requires analytical data about the content. For such purposes was developed and validated a method based on the optical emission spectroscopy coupled with inductively coupled plasma (ICP-OES). Minerals and elements were extracted using two conventional methods (Soxhlet and maceration) and two non-conventional (ultrasound- and microwave-assisted techniques). The extracts were analyzed resulting in high diversity in the composition. Non-conventional techniques showed better results, since those extracts possessed high content of the macroelements and iron as well, instead the toxic elements were found in trace amount