Josip Juraj Strossmayer University of Osijek. Department of Chemistry. Department of Analytical, Organic and Applied 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.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
