20.500.12556/DKUM-93612 CMC kationskih površinsko aktivnih snovi v vodni raztopini kohumulona magistrsko delo CMC of cationic surfactants in aqueous cohumulone solutions Kohumulon je ena izmed α-kislin v hmelju, ki se uporablja na različnih področjih od pivovarstva do farmacije. Kohumulon deluje protibakterijsko, med drugim zaradi sposobnosti poškodovanja celične membrane, zato je raziskovanje njegovih interakcij s površinsko aktivnimi snovmi (PAS) ključnega pomena. V raziskavi smo določali kritično micelno koncentracijo (CMC) treh kationskih površinsko aktivnih snovi: DTAB, TTAB in HTAB ter spremljali vpliv kohumulona na te vrednosti. Raziskavo smo začeli z opazovanjem emisijskega in absorpcijskega spektra kohumulona v območju UV in vidne svetlobe. Nato pa določali CMC površinsko aktivnih snovi s fluorescenčno spektroskopijo in opazovali vpliv dodatka kohumulona na CMC PAS. Uspešno smo določili CMC PAS s pirenom, vendar določitev CMC s pirenom v prisotnosti kohumulona ni bila mogoča, saj je bila absorbanca kohumulona previsoka. Zato smo uporabili alternativo – fluorescein – s katerim smo uspešno določili CMC. Ugotovili smo, da kohumulon pri DTAB in TTAB zniža CMC, pri HTAB pa jo nekoliko poveča. Prisotnost 1 % etanola, ki je bil potreben za raztapljanje kohumulona, ni imela pomembnega vpliva na CMC. Zaznali smo tudi pojav bele oborine ob dodatku PAS v raztopino kohumulona, ki je izginila tik pred dosegom CMC, kar dodatno potrjuje mehanizem micelizacije. Cohumulone is one of the α-acids in hops, used in various fields ranging from brewing to pharmaceuticals. Cohumulone exhibits antibacterial activity, likely due to its ability to damage the cell membrane, which makes studying its interactions with surfactants essential. In this thesis, we determined the critical micelle concentration (CMC) of three cationic surfactants: DTAB, TTAB, and HTAB, and monitored the influence of cohumulone on these values. Initially, we determined the effect of solvent polarity on cohumulone using UV–VIS and fluorescence spectra. Then we determined the CMC of the surfactants using fluorescence spectroscopy and observed how the addition of cohumulone affected their CMC values. The CMC of the surfactants was successfully determined using pyrene, but determining the CMC with pyrene in the presence of cohumulone was not possible due to the high absorbance of cohumulone. Therefore, we used an alternative – fluorescein – with which we successfully determined the CMC. We found that cohumulone lowers the CMC of DTAB and TTAB, while slightly increasing the CMC of HTAB. The presence of 1% ethanol required to dissolve cohumulone had no significant effect on the CMC. We also observed the appearance of a white precipitate upon adding surfactants to the cohumulone solution, which disappeared just before reaching the CMC, further confirming the micellization mechanism. kohumulon CMC UV–VIS spektroskopija fluorescenčna spektroskopija piren fluorescein cohumulone CMC UV–VIS spectroscopy fluorescence spectroscopy pyrene fluorescein true true false [T. Galun] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-07-06 18:41:37 2025-07-16 13:34:25 2025-07-26 03:13:37 0000-00-00 00:00:00 2025 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (XI, 48 f.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 543.42:544.77.051.62(043.2) 243889411 MAG_Galun_Tamara_2025.pdf MAG_Galun_Tamara_2025.pdf 1 83B29C73DF4892AE3FD9CEB0A1ABE94B a8bb5f048074ba433a6b899f2c437e7a088f821d520a361a0938988c5fb65641 a2b464a1-62ed-11f0-9944-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=193721 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0