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undergraduate thesis
Određivanje kofeina u čaju
Osijek: Josip Juraj Strossmayer University of Osijek, Department of Chemistry, 2017. urn:nbn:hr:182:184415
Ravnjak, Gabriela
Josip Juraj Strossmayer University of Osijek
Department of Chemistry
Department of Analytical, Organic and Applied Chemistry

Institutional repository: Repository of the Department of Chemistry, Osijek

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Ravnjak, G. (2017). Određivanje kofeina u čaju (Undergraduate thesis). Osijek: Josip Juraj Strossmayer University of Osijek, Department of Chemistry. Retrieved from https://urn.nsk.hr/urn:nbn:hr:182:184415

Ravnjak, Gabriela. "Određivanje kofeina u čaju." Undergraduate thesis, Josip Juraj Strossmayer University of Osijek, Department of Chemistry, 2017. https://urn.nsk.hr/urn:nbn:hr:182:184415

Ravnjak, Gabriela. "Određivanje kofeina u čaju." Undergraduate thesis, Josip Juraj Strossmayer University of Osijek, Department of Chemistry, 2017. https://urn.nsk.hr/urn:nbn:hr:182:184415

Ravnjak, G. (2017). 'Određivanje kofeina u čaju', Undergraduate thesis, Josip Juraj Strossmayer University of Osijek, Department of Chemistry, accessed 27 November 2024, https://urn.nsk.hr/urn:nbn:hr:182:184415

Ravnjak G. Određivanje kofeina u čaju [Undergraduate thesis]. Osijek: Josip Juraj Strossmayer University of Osijek, Department of Chemistry; 2017 [cited 2024 November 27] Available at: https://urn.nsk.hr/urn:nbn:hr:182:184415

G. Ravnjak, "Određivanje kofeina u čaju", Undergraduate thesis, Josip Juraj Strossmayer University of Osijek, Department of Chemistry, Osijek, 2017. Available at: https://urn.nsk.hr/urn:nbn:hr:182:184415

Metadata
TitleOdređivanje kofeina u čaju
Title (english)Determination of caffeine in tea
AuthorGabriela Ravnjak
MentorMirela Samardžić (mentor)
GranterJosip Juraj Strossmayer University of Osijek
Department of Chemistry
(Department of Analytical, Organic and Applied Chemistry)
Osijek
Defense date and country2017-09-18, Croatia
Scientific / art field,
discipline and subdiscipline		NATURAL SCIENCES
Chemistry
Analytic Chemistry
Abstract
Kofein je prirodni alkaloid koji se nalazi u biljnim vrstama koje pretežno rastu u tropskim ili suptropskim regijama svijeta. Njegovi glavni izvori su zrna kave i listovi čaja. U ovom radu opisana je izolacija kofeina iz pet vrsta čaja, te su određeni njegovi maseni udjeli u pojedinoj vrsti. Korištena metoda za izolaciju je ekstrakcija na osnovu različite topljivosti između dva otapala, a maseni udjeli kofeina određeni su gravimetrijski. Potom su apsorbancije i masene koncentracije određene pomoću UV-Vis spektroskopije. Rad je podijeljen u nekoliko poglavlja. Iza uvoda slijedi literaturni pregled gdje su ukratko prikazana svojstva kofeina te korištene metode za njegovu izolaciju. Zatim slijedi prikaz dobivenih rezultata a na kraju zaključak i upotrijebljena literatura.
Abstract (english)
Caffeine is a natural alkaloid that is found in plant species that predominantly grow in tropical or subtropical regions of the world. Its main sources are coffee beans and tea leaves. This paper describes the isolation of caffeine from five types of tea, and determination of its mass fraction in each particular species. The method that was used for isolation is the extraction based on the different solubility of the two solvents, and the mass of caffeine is determined gravimetrically. Then absorbance and mass concentration were determined by UV-Vis spectroscopy. The paper is divided into several chapters. Introduction chapter is followed by literature review where the caffeine properties and the methods used for its isolation are briefly resented. Next, is a summary of the results obtained and finally the conclusion and the used literature.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:182:184415
Study programmeTitle: Chemistry
Study programme type: university
Study level: undergraduate
Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) kemije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) kemije)
Type of resourceText
File originBorn digital
Access conditionsOpen access
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Created on2018-01-10 08:57:18