UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

Undergraduate Theses

Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/13

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1998 - 199912000 - 20053

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End date: 2009Degree: search.filters.degree.Bachelor of Science in Chemistry

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    Geochemical association of Cr, Cu, Ni, and Pb in the sediments of Iloilo River estuary
    Arban, John Paul B. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2005-04)
    The geochemical association of Cr, Cu, Ni, and Pb in the sediments of Iloilo River Estuary has been studied using a modified Tessier’s sequential extraction procedure. The results obtained show that most of the metals studied are mostly associated in the residual and organic matter fractions of the sediment samples (Cr: 66.26% - 74.36% in the residual,15.43% - 24.08% in the Fe-Mn oxide fraction, 8.14% - 12.71% in organic matter fraction, and 0.000% - 2.996% in the exchangeable/carbonate fraction; Cu: 39.30% - 46.73% in the residual, 12.00% - 52.18% in the organic fraction, 3.227% - 11.41% in the Fe-Mn fraction, and 0.000% - 17.43% in the exchangeable/carbonate fractions; Ni: 42.75% - 57.02% in the organic matter fraction, 24.93% - 39.33% in the residual, 5.814% - 14.15% in the Fe-Mn fraction, and 5.504% - 13.12% exchangeable/carbonate fraction; and Pb in sample AAA-21: 48.02% in the residual, 38.55% in the organic matter fraction, and 7.33% in the Fe-Mn fraction, and 6.078% in the exchangeable/carbonate fraction). The analysis of the total metal concentrations of the sediment samples taken from Iloilo River are found to be above the reported concentration of uncontaminated sediment except for Pb in sediment sample AAA-21 (Chromium: 102.1 ug/g - 150.5 pg/g; Copper: 62.56 pg/g - 111.7 pg/g; Nickel: 53.40 pg/g - 75.44 pg/g; and Lead in sample AAA-21: 22.21 pg/g). The study shows that about 50% of the total metal concentration in the sediment samples are bioavailable to the aquatic organisms.
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    Chromatographic analysis and antibacterial assay of Avicennia officinalis bark extracts
    Janagap, Steve P. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2003-04)
    In this study, the antibacterial activity and the chemical constituents of Avicennia officinalis bark were determined. The antibacterial assay showed that the dichloromethane (DCM) fraction at 1000 ug/mL was most effective against the tested bacteria especially to Staphylococcus aureus. It had a microbial index of 0.97 while the positive control, amoxicillin had 1.00. The aqueous fraction did not show antibacterial activity to the organisms tested. A number of chemical constituents were found to be present in the different fractions obtained from Avicennia officinalis bark: alkaloids, cardiac glycosides, flavonoids, phenolic compounds, saponins and terpenes. These constituents were determined using thin layer chromatography. The DCM fraction which showed the highest bioactivity, had the most number of components while the aqueous fraction had the least number of components. The DCM fraction was subjected to two-dimensional thin layer chromatography. Nine spots were observed with the first solvent system (ethyl acetate-DCM; 5:3) while eleven spots were observed with the second solvent system (ethyl acetate-n-hexane-DCM; 2:1:1).
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    Bioactivity-guided screening of selected plants from UPV Miag-ao campus
    Arceo, Ma. Ofelia H. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 1998-05)
    Twelve selected ethnomedically-used plants were screened for alkaloids, saponins, and flavonoids. Nine out of twelve plants contained at most two of the phytochemicals tested, and three showed the absence of these phytochemicals. Methanolic extracts of three selected plants (Stachy/arpheta /amaicensis, Hyptis suaveo/ens, Semecarpus philippinensis) were examined for antibacterial activity against Staphylococcus aureus. Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. All extracts were found to be active at least against two of the microorganisms tested. The extract of Siachytarphe/a jamaicensis was found to be active against three out of four microorganisms and found to be the most bioactive. Stachyiarpheta jamaicensis was subjected to bioactivity-guided fractionation using solvents of increasing polarity - hexane, ethyl acetate, and n-butanol. The hexane extract was considered as the most bioactive fraction. Its chromatogram contained seven spots in which four turned blue violet after spraying with vanillin-H2SO4. The color change exhibited suggests the possible presence of saponins.
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    Proximate analysis and fatty acid profile of Hyopila rosea Williams and Vesicularia reticulata
    Anuevo, Gwen M. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2000-07)
    Philippine mosses number about 506 species. Hyophila rosea Williams and Vesicularia reticulata are the two species that are found abundantly in Panay area. Hyophila rosea Williams are medium-sized plants in thin clusters with stems from 1-1.5 cm high. Proximately characterized to contain 17.82% moisture, 5.99% crude protein, 7.69% crude ether extract, 21.42% crude fiber, 18.21% ash, and 46.69% nitrogen-free extract. Fatty acid profiles are composed of twenty-nine (29) analytes, from which twenty (20) were not identified while nine (9) are known, starting from Caproic acid (C1o) to Arachidic (C20). Linoleic, palmitic, and oleic acids are the first three analytes comprising higher percentages. Vesicularia reticulata, on the other hand, are dull, yellowish green, and the main stem is about 5 cm long. Proximately characterized to contain 12.73% moisture, 5.96% crude protein, 9.45% crude ether extract, 21.95% crude fiber, 32.67% ash, and 29.96% nitrogen-free extract. Fatty acid profiles are composed of forty-one (41) analytes, from which thirty-two (32) analytes were not identified, while nine (9) analytes are known starting from C1o to C2o.Linoleic, palmitic and linolenic acids are the first three analytes comprising higher percentages.