20.500.12556/DKUM-94952 Vpliv Ph na kinetiko oksidacije galne kisline diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje Effect of Ph on the kinetics of gallic acid oxidation Galna kislina je polifenol, ki je osnovni gradnik galotaninov. V naravi so te spojine zelo razširjene v rastlinah in sadju, zato jih ljudje zaužijemo s hrano, uporabljajo pa jih tudi kot konzervanse. Fenolne spojine, med katere spada tudi galna kislina, so pomembne bioaktivne spojine v rastlinskih živilskih izdelkih. Zaradi njih naj bi uživanje hrane rastlinskega izvora ugodno vplivalo na zdravje. Pomembne so tudi raziskave njihove stabilnosti in kateri dejavniki vplivajo nanjo, saj oksidacija fenolnih spojin močno vpliva na lastnosti živil. Izkazalo se je, da je glavni dejavnik zniževanja koncentracije fenolnih spojin oksidacija, oksidacija enega izmed polifenolov, galne kisline, je tudi tema diplomske naloge. Diplomska naloga zajema pripravo raztopine galne kisline v pufrih z različnim pH (5,0; 6,0; 7,0; in 7,4) ter študijo kinetike razpada galne kisline s pomočjo spektrometrije UV-Vis. Preučevanje kinetike je ključnega pomena, saj omogoča vpogled v stabilnost galne kisline, pogoje, pod katerimi ostane stabilna in dejavnike, ki vplivajo na njeno oksidacijo. Pri sami izvedbi poizkusa bi na samo ponovljivost eksperimenta lahko vplivala koncentracija kisika v raztopini, saj neprestano niha in je odvisna od številnih faktorjev. To bomo rešili s prepihovanjem vzorca z dušikom, saj bomo tako izgnali kisik iz raztopine. Raztopini smo nato dodali določeno koncentracijo vodikovega peroksida, ki deluje kot oksidant. Poizkusili bomo še poiskati reakcijski mehanizem, s katerim bi popisali oksidacijo galne kisline v raztopinah in določiti konstante reakcijske hitrosti. Seveda želimo tudi pojasniti, kako različni parametri vplivajo na konstante reakcijske hitrosti. Gallic acid is a polyphenol, which is the basic building block of gallotannins. In nature, these compounds are widespread in plants and fruits, which is why people consume them with food, and they are also used as preservatives. Phenolic compounds, which include gallic acid, are important bioactive compounds in plant food products. Because of them, the consumption of plant-based foods is said to have a beneficial effect on health. Research into their stability and which factors affect it is also important, since the oxidation of phenolic compounds strongly affects the properties of foods. It turned out that the main factor in reducing the concentration of phenolic compounds is oxidation, the oxidation of one of the polyphenols, gallic acid, is also the topic of the diploma thesis. The diploma thesis includes the preparation of a solution of gallic acid in buffers with different pH (5.0; 6.0; 7.0; and 7.4) and the study of the kinetics of the decomposition of gallic acid using spectrometry UV-Vis. Studying kinetics is crucial, as it provides insight into the stability of gallic acid, the conditions under which it remains stable, and the factors that affect its oxidation. When performing the experiment itself, the reproducibility of the experiment could be affected by the concentration of oxygen in the solution, as it constantly fluctuates and depends on many factors. We will solve this by purging the sample with nitrogen, as this will drive oxygen out of the solution. We then added a certain concentration of hydrogen peroxide to the solution, which acts as an oxidant. We will also try to find a reaction mechanism with which to describe the oxidation of gallic acid in solutions and determine the reaction rate constants. Of course, we also want to explain how various parameters affect the reaction rate constants. oksidacija vodikov peroksid galna kislina konstanta kemijskega ravnotežja oxidation hydrogen peroxide gallic acid chemical equilibrium constant true true false [M. Jalovec] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2025-08-29 20:45:06 2025-09-10 15:36:34 2025-09-20 03:15:55 0000-00-00 00:00:00 2025 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (VIII, 37 str.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 542.943:547.58(043.2) 249598467 VS_Jalovec_Matjaz_2025.pdf VS_Jalovec_Matjaz_2025.pdf 1 E3CCC6BF40D9CE4DD7D8F15A32BAE1BB ff3fb147745c9960dc30fa8bd02fc545f260b8072acf8fdbeb0b712d92b176d0 d1b7defc-8d59-11f0-9299-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=197978 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0