diplomsko delo univerzitetnega študijskega programa I. stopnje
Miha Fermišek (Author), Urban Bren (Mentor), Gregor Hostnik (Co-mentor)

Abstract

Tanini so rastlinski sekundarni metaboliti, ki rastline ščitijo pred okoljskim stresom in rastlinojedimi živalmi. Industrijsko so pomembni za strojenje usnja, proučuje pa se tudi njihova zmožnost zaviranja rasti bakterij. Pri tem igrajo pomembno vlogo interakcije taninov z esencialnimi kovinskimi ioni. Delo smo začeli z izolacijo veskalina in kastalina iz kostanjevega ekstrakta Farmatan, čemur je sledila študija koordinacijskih spojin veskalina s Fe(II) ioni pri različnih vrednostih pH. Ločbo taninov smo izvedli s hitro (flash) tekočinsko kromatografijo, pri kateri smo uporabili stacionarni fazi Sephadex LH-20 ter C18. Mobilne faze, uporabljene pri kromatografiji na stacionarni fazi Sephadex LH-20, so bile voda, metanol in aceton, na stacionarni fazi C18 pa voda in acetonitril. Ločbo smo nadaljevali z uporabo preparativne tekočinske kromatografije visoke ločljivosti na stacionarni fazi C18, kjer smo kot eluente uporabili vodo in acetonitril. Med samim postopkom ločbe smo posamezne frakcije analizirali z uporabo tekočinske kromatografije visoke ločljivosti na stacionarni fazi C18 z eluentoma vodo in acetonitrilom. Topila smo po vsaki ločbi odstranjevali z uporabo rotacijskega uparjalnika in liofilizacijo. Na ta način smo izolirali veskalin in kastalin s 94- in 93-odstotno čistostjo. Sledila je študija interakcij veskalina z Fe(II) ioni. Tvorbo koordinacijskih spojin med veskalinom in Fe(II) pri različnih vrednostih pH smo proučevali z uporabo UV/Vis spektroskopije. Najprej smo izmerili spekter veskalina v 0,01 M HCl in v acetatnem pufru (pH = 5,5). Nato smo izmerili še absorpcijski spekter koordinacijske spojine med veskalinom in Fe(II) ioni. Za tem smo pripravili raztopine z različnim razmerjem veskalina in Fe(II) ionov ter izrisali Jobov diagram. Iz molskega razmerja med veskalinom in Fe(II) ioni smo določili stehiometrijsko razmerje koordinacijske spojine veskalina in Fe(II) ionov kot 1:2.

Keywords

tanini;veskalin;izolacija;koordinacijska spojina;UV/Vis spektroskopija;Jobov diagram;diplomske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [M. Fermišek]
UDC: 675.014.4(043.2)
COBISS: 79723523 Link will open in a new window
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Downloads: 65
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Other data

Secondary language: English
Secondary title: Formation of coordination compounds between hydrolysable tannins and Fe (II)
Secondary abstract: Tannins represent secondary plant metabolites, that protect plants from environmental stress and herbivores. In industry, they are involved in the production of leather and are currently being studied in detail for their beneficial properties, which include the prevention of bacterial growth. Here they play an important role in the interactions between tannins and essential metal ions. The study starts with the isolation of vescalin and castalin from chestnut extract Farmatan, followed by the formation of coordination compounds between vescalin and Fe(II) ions at different pH values. Separation of tannins was performed by flash liquid chromatography, where we used Sephadex LH-20 and C18 as stationary phases. Mobile phases for the Sephadex LH-20 stationary phase were water, methanol and acetone, while mobile phases for the C18 stationary phase were water and acetonitrile. Separation was continued by preparative high-performance liquid chromatography on the C18 stationary phase using water and acetonitrile as eluents. During the separation process, we analyzed several fractions by high-performance liquid chromatography using C18 as stationary phase and water and acetonitrile as eluents. Solvents were removed after each separation step using a rotary evaporator and liofilization. In this way, we were able to isolate vescalin and castalin with a purity of 94 and 93 % respectively. Vescalin was then used to study the interactions with Fe(II) ions. The formation of coorination compounds between vescalin and Fe(II) at different pH values was studied by using UV/Vis spectroscopy. First, the spectrum of vescalin was measured in both 0,01 M HCl and acetate buffer (pH = 5,5). Then we measured the absorption spectrum of the coordination compound between vescalin and Fe(II) ions. Later, we prepared solutions with different ratios of vescalin and Fe(II) ions and drew the Job plot. From the mole fractions between vescalin and Fe(II) ions, we determined the stoichiometriy ratio of vescalin and Fe(II) ions in the coordination compound as 1:2.
Secondary keywords: tannins;vescalin;isolation;coordination compound;UV/Vis spectroscopy;Job plot;
Type (COBISS): Bachelor thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: X, 37 str.
ID: 13284060