https://www.lmaleidykla.lt/ojs/index.php/chemija/issue/feed 2024-04-04T19:11:03+03:00 Executive Secretary aldonaj@ktl.mii.lt Open Journal Systems <p><em>Chemija</em> publishes original research articles and reviews from all branches of modern chemistry, including physical, inorganic, analytical, organic, polymer chemistry, electrochemistry, and multidisciplinary approaches. The journal is covered by <em>Clarivate Web of Science</em> since 2007. 2022 impact factor 0.6, 5-year impact factor 0.5.</p> https://www.lmaleidykla.lt/ojs/index.php/chemija/article/view/5266 2024-04-04T19:06:53+03:00 Lietuvos mokslų akademija ojs@lmaleidyba.lt 2024-04-03T00:00:00+03:00 Copyright (c) https://www.lmaleidykla.lt/ojs/index.php/chemija/article/view/5267 2024-04-04T19:09:17+03:00 Lietuvos mokslų akademija ojs@lmaleidyba.lt 2024-04-03T00:00:00+03:00 Copyright (c) https://www.lmaleidykla.lt/ojs/index.php/chemija/article/view/5263 2024-04-04T19:11:03+03:00 Jurgita Daukšienė deividas.burdulis@lsmu.lt Kristina Burdulienė deividas.burdulis@lsmu.lt Gediminas Daukšys deividas.burdulis@lsmu.lt Lauryna Paulauskaitė deividas.burdulis@lsmu.lt Deividas Burdulis deividas.burdulis@lsmu.lt

<div class="page" title="Page 1"> <div class="section"> <div class="layoutArea"> <div class="column"> <p>Phenolic compounds are well-known phytochemicals found in many types of plants. Phenolic compounds and flavonoids are potential substitutes for bioactive agents in pharmaceutical and medicinal sections to promote human health and prevent and cure different diseases. Lingonberry (Vaccinium vitis-idaea L.) belongs to the Ericaceae family. It is widely spread in the northern hemisphere in such countries as Russia, Lithuania, Latvia, Iceland, Scandinavian countries, etc. Lingonberry fruits are beneficial due to their anti-inflammatory, antibacterial, antioxidative activities and effect on the cardiovascular system. Although a number of studies are done on phenolic compound extraction methods, there is a high need of evidence on the most efficient way of raw material preparation. In this research, various lingonberry (Vaccinium vitis-idaea L.) fruit raw material preparation methods will be compared.</p> </div> </div> </div> </div>

2024-04-03T00:00:00+03:00 Copyright (c) https://www.lmaleidykla.lt/ojs/index.php/chemija/article/view/5264 2024-04-04T19:10:49+03:00 Vytautas Kavaliauskas audrius.padarauskas@chgf.vu.lt Audrius Padarauskas audrius.padarauskas@chgf.vu.lt

<div class="page" title="Page 1"> <div class="section"> <div class="layoutArea"> <div class="column"> <p>This work demonstrates that an aqueous two-phase system (ATPS) is formed when a small amount of acetonitrile (ACN) is added to the aqueous hexafluoroisopropanol (HFIP) solution. The effect of ACN amount on the volume of the formed HFIP/ACN phase was investigated. It was also shown that relatively hydrophilic methylene blue was completely extracted into the HFIP/ACN phase whereas its extractability with conventional solvents (hexane, CH2Cl2 and CHCl3) was significantly lower. The obtained results suggest that the HFIP/ACN phase exhibits a relatively high polarity and should be a good choice for the extraction of moderately or even highly polar compounds from aqueous samples. Finally, the developed ATPS was applied for the homogeneous liquidliquid microextraction of four cationic dyes from river water samples prior to HPLC analysis. Under optimised extraction conditions, the enrichment factors were around 150. Calibration curves were linear (R2 ≥ 0.9959) for the concentration level between 0.2–0.5 and 50.0 μg/L and the detection limits were in the range 0.05–0.18 μg/L. The recoveries of the dyes for the spiked water samples were 88.6–98.5%, with the relative standard deviation values less than 9.6%.</p> </div> </div> </div> </div>

2024-04-03T00:00:00+03:00 Copyright (c) https://www.lmaleidykla.lt/ojs/index.php/chemija/article/view/5265 2024-04-04T19:10:35+03:00 Vida Vičkačkaitė vida.vickackaite@chf.vu.lt Vasarė Viselgaitė vida.vickackaite@chf.vu.lt Vilius Poškus vida.vickackaite@chf.vu.lt

<div class="page" title="Page 1"> <div class="section"> <div class="layoutArea"> <div class="column"> <p>A novel, cost-effective, simple and environmentally friendly method was developed for separating, preconcentrating and quantifying volatile analytes. That approach utilised switchable hydrophilicity solvent-based hollow fiber liquid-liquid microextraction in combination with headspace gas chromatography. The extraction was carried out from 1 l of water solution. 100 μl of nonanoic acid, immobilised within a polypropylene capillary, was selected as an extraction solvent. After the extraction, the capillary with the extract was transferred to a headspace vial, and headspace gas chromatographic analysis was performed. To facilitate the transition of volatile analytes to the headspace for subsequent analysis, nonanoic acid was converted to hydrophilic nonanoate by adding a sodium hydroxide solution.</p> <p>The effectiveness of the suggested strategy was demonstrated in the determination of benzene and its derivatives in water samples. Various parameters affecting the extraction and headspace gas chromatographic determination were investigated and optimised. Under the optimal conditions, the analytical characteristics of the proposed technique were determined.</p> <p>Using this approach, the limits of quantification for all analytes were found to be below the maximum acceptable concentration.</p> </div> </div> </div> </div>

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