UPV Digital RepositoryUPV-DRUniversity of the Philippines Visayas
 

Undergraduate Theses

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

Browse

Filters

Settings

Degree: search.filters.degree.Bachelor of Science in ChemistryDepartment: search.filters.department.College of Arts and Sciences

Search Results

Now showing 1 - 9 of 9
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    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).
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    Optimization of pH, sorbent dose, and contact time in biosorption of Cu, Cd and Pb in sugarcane bagasse in a tri-metal aqueous system
    Abetria, Pauline Grace R. (Department of Chemistry, College of Arts and Sciences, Univsersity of the Philippines Visayas, 2013-04)
    Adsorption is one of the physicochemical treatment processes found to be effective in removing heavy metals from aqueous solutions. The biosorption of Cu, Cd, and Pb in sugarcane bagasse in a tri-metal aqueous system was optimized for pH, sorbent dose, and contact time using Doehlert design and it was found that the optimal values are pH 5, a sorbent dose of 1.33g sorbent/mg metal, a contact time of 4 hours, and the available sites on the sorbent for metal binding were influenced by pH. Furthermore, the effect of initial metal concentration on the metal uptake of the sorbent was also studied and it was found that at increasing metal concentrations the metal uptake also increased at a fixed (optimum) sorbent dose. The sorbent affinity was observed to be increasing in favor of increasing ionic radius, Cu < Cd < Pb, at relatively low metal concentrations and Cd < Cu < Pb at relatively high metal concentrations. Each metal behaved differently on the sorbent. Copper obeyed the Langmuir isotherm whereas cadmium and lead both obeyed the Freundlich isotherm. Finally, the IR spectrum of the sorbent was elucidated and -OH and -COOH groups were present but complexation was absent. Hence, in a tri-metal aqueous system containing Cu, Cd and Pb, the biosorption process in bagasse is proposed to be by physical adsorption.
  • Thumbnail Image
    Item
    Determination of the anthocyanin content in Hibiscus sabdariffa L. (Roselle) calyses from fresh to spray-dried form
    Arganioza, Hannah Mae C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    Hibiscus sabdariffa L. is an agricultural herb with calyces as the commercially important part this plant. The calyces is a good source of anthocyanin (pigments) with several potential applications in the food, pharmaceutical and cosmetic industries. These pigments are used worldwide in the production of drinks and as a source of natural food coloring. However, these pigments are very unstable due to processing and storage conditions. Thus, this present study investigated the amount of anthocyanin as it is processed into a commercial product in the form of spray-dried powder. The Roselle plant samples were obtained from Herbanext Laboratories farm. The fresh extract has 493.45 mg/L total monomeric anthocyanin. Compared to the fresh extract, concentrated aqueous spray-dried extract (261.06 mg/L) contains lower anthocyanin content, however, this is significantly higher than aqueous concentrate (124.41 mg/L). Both the aqueous extract and ethanolic extract contains the smallest amount of anthocyanin for each sets. Spray drying techniques increases the amount of anthocyanin which helps to prevent further degradation of the compound due to the influences of the storage environment and processing conditions.
  • Thumbnail Image
    Item
    Optimization of extraction Conditions of water-soluble phenolics from tawa-tawa (Euphorbia hirta L.) based on Densitometric TLC using gallic acid as marker compound
    Aborka, Ma. Ayanne B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    The present study aimed to optimize the extraction conditions of water-soluble phenolics for tawa-tawa (Euphorbia hirta L.) with gallic acid as the compound of interest. Water was used as extraction solvent. The effect of the interactions of different extraction temperature (50°C, 60°C and 70°C) and extraction time (20 min, 40 min and 60 min) were investigated. To evaluate the importance of the parameters on the extraction efficiency of gallic acid, a factorial design was used. The normal probability plot and estimates of standard error showed that time and temperature were both significant parameters. It further showed that time was a more significant contributor than temperature to the extraction efficiency of gallic acid. The results revealed that interaction of time and temperature did not have significant effects. The ANOVA results showed that only extraction parameter with significant effect was time (p < 0.05). Temperature and its interaction with time did not have significant effects. Based on the desirability values generated by Design-Expert 9.0.4, the optimal conditions in extracting gallic acid were the following: extraction time of 60 minutes and extraction temperature of 70°C. Results of FTIR analysis confirmed the presence of the following functional groups: O-H, C=O, C-O, C-H (aromatic), C=C (benzene) and out-of-plane bending or oops. Gallic acid in tawa-tawa is present in esterified form and exists as part of hydrolysable tannins.
  • Thumbnail Image
    Item
    Optimization of lead (II) adsorption of EDTA-functionalized magnetic graphene oxide using response surface methodology
    Angeles, Christine Debbie Shanne V. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)
    Chronic intake of lead-contaminated water, even at low concentrations, can cause damage to the digestive, reproductive, and nervous systems. To effectively remove lead in water, solid phase extraction or adsorption is being used. In this study, EDTA-functionalized magnetic graphene oxide (EmGO) adsorbent was fabricated using a stepwise modification of graphene oxide (GO). It was characterized using SEM, FTIR, and XRD. EmGO was shown to have improved adsorption capacity towards Pb(II) in natural water. Also, the magnetic property of the adsorbent allowed an easier and more convenient mean of retrieval. The generated response surface model from Box- Behnken design (BBD) approximated the optimum condition for maximum removal efficiency of EmGO. Based on the results, the model had a 0.9113 (±0.0001) overall desirability, optimum values for pH, adsorbent dosage, and contact time were 5.99 (±0.01), 12.2135 (±0.0001), and 48.39 (±0.01), respectively. The highest percent removal efficiency of EmGO in the experiment was determined to be 73.41 (±0.01)%.
  • Thumbnail Image
    Item
    Antioxidant and antibacterial activities of bika (Ampelocissus martini panch) seed oil
    Angot, Rose Imee Lyn N. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    Ampelocissus martini Planch, locally known as Bika, is a native tropical plant generally found in Southeast Asia. It is abundant in Panay Island, particularly in the provinces of Antique and Iloilo. Despite that the fruit is being consumed as food, used as medicine, and made into wine, very few scientific studies pertaining to Bika grape exist. Hence, this study focused on its antioxidant and antibacterial activities. The antioxidant activities were carried out through the % DPPH radical scavenging activity and reducing power method. Results show that the Bika seed oil has antioxidant activity. Its IC50 using DPPH assay is 23.63 ppm. Moreover, it also showed a significant antioxidant activity based on the results from the reducing power assay. Both results demonstrated that Bika grape seed oil have antioxidant activity. On the other hand, the mean zones of inhibition using disk diffusion assay was used to assess the antibacterial activity of Bika seed oil against Escherichia coh and Staphylococcus aureus. Only the antibiotic Gentamicin showed active antibacterial property, whereas the Bika seed oil showed little zone of inhibition, only goes to show that it has an inactive antibacterial property.