Chemistry

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Browsing Chemistry by Author "Abebayehu, Mekonnen (PhD)"

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    Extraction and Purification of Betanin from Red Beetroots and Synthesis of Co(Ii), Cu(Ii) and Zn(Ii) Based Betanin Metal Complexes
    (Addis Ababa University, 2020-02-02) Tessema, Getachew; Abebayehu, Mekonnen (PhD)
    For this study, red beetroots were used as a source of betanin. Betanin extraction process was carried out by using methanol as a solvent. Column chromatography method was used to purify the extracted betanin and to isolate the purified betanin by slightly increasing the polarity of the solvent. The absorption spectra of the extracted and purified sample was efficiently monitored and recorded in the UV-Vis region (200–800 nm) by using Perkin Elmer, Lambda 950 UV/Vis/NIR scanning spectrometer with methanol reference. As observed from the experimental result, the maximum absorption spectra of pure betanin is around λmax 540 nm is comparable result with absorption spectra data of pure betanin in different literatures. Ferric reducing power method was applied with slight modification to study the reducing capacity of betanin. Reducing power assay method to evaluate antioxidant ability was based on the reduction of Fe3+ to Fe2+ in which the yellow color of the test solution changes to various shades blue, which indicates the reducing capacity of the sample. Purified betanin were subjected to complexation with Co2+, Cu2+ and Zn2+. As observed from the experimental results, maximum absorption spectra of newly synthesized betanin-metal complexes showed blue shifting absorption spectra compared with absorption spectra of pure betanin. Finally, X-ray diffraction technique was used to draw conclusion about the structure and phase purity of the newly synthesized metal complexes. X-ray diffraction spectra results showed that the constituents of the resulting betanin-metal complex solids are arranged with no particular order indicating they are amorphous solids.
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    Synthesis of Iron-Iii and Chromium-Iii Based Metal-Betanin Complexes Using Betanin as a Natural Ligand Isolated from Beetroot
    (Addis Ababa University, 2020-07-07) Gebeyehu, Aklilu; Abebayehu, Mekonnen (PhD)
    The aim of this research work was to isolate betanin from beetroot (Beta vulgaris L.), investigate the antioxidant activity of betanin, synthesis of betanin-iron (III) and betanin-chromium (III) complexes and characterization. The beetroot was collected from Meri local market, Addis Ababa. The essential compounds were extracted by solvent extraction and purified by liquid column chromatography. The result was determined by UV-Vis spectral studies. The analysis result indicates betanin is one of a beetroot component was observed at a peak of 538 nm wavelength. Structurally, betanin can potentially act as a bidentate ligand and can be used for complex formation. This study investigated the anti-oxidant activity of betanin, synthesis of betanin-iron (III) and betanin-chromium (III) complexes and characterization. The ferric reducing power method was applied for anti-oxidant measuring of blue colour which is an indicator of higher antioxidant properties of betanin. The complex formation between Cr (III) and Fe (III) and betanin was carried out in distilled water. The resulting complexes were characterized by UV-Vis and XRD spectral studies. The UV-Vis spectral analysis results of iron (III)-betanin and chromium (III)-betanin complexes were at a wavelength of 358 nm and 458 nm respectively. This shows that betanin were inducing a blue-shifting due to the coordination or aggregation between iron (III) and chromium (III) to betanin. The XRD analysis results were also irregular base line. This indicates that the presence of amorphous phase within the sample.