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Undergraduate Theses

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

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Committee Chair: search.filters.chair.Janagap, Steve P.SDG: search.filters.sdg.SDG 9 - Industry, innovation and infrastructure

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    Physicochemical characterization and FTIR Analysis of the essential oil from Almaciga (Agathis philippinensis Warb) gum
    Briones, Kathleen Faith C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-02)
    Almaciga (Agathis philippinensis ) is one of the few conifer timber species endemic to the Philippines. It is highly valued for its resin which is the world- renowned Manila copal (hard resin). Manila copal have been reportedly employed in treating asthma, headaches, myalgia and even arthritis. An ethnomedical documentation of Manila copal usage also reported the utilization of the resin for stomachache, ulcers and dysentery. However, there is only limited literature regarding the Almaciga gum (the softer resin). To provide supplemental data regarding the Almaciga gum, this study was conducted to characterize the physicochemical properties and to identify the major functional groups of the essential oil extracted from its resin. The essential oil was extracted using a makeshift steam distillation set- up with a total yield of 3.20%. The essential oil was found to have a refractive index of 1.4731± 0.0002, a density of 0.8502±0.0039 g/mL, and a specific gravity of 0.8527±0.0039. Odor, color and appearance were evaluated using the organoleptic method. Major functional groups were identified from Fourier Transform - Infrared Spectroscopy (FTIR) which suggested that limonene is the major component.
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    Antimicrobial, antioxidant and phytochemical properties of ethanolic and water extracts of selected local spices from Miagao, Iloilo
    Besinga, Yvonne Grace M. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)
    Spices such as garlic, pepper and turmeric are indispensable in the daily food preparation and are reported to have compounds which prevent the microbial spoilage of food. This study evaluates the antimicrobial and antioxidant activities as well as the phytochemical properties of the ethanol and aqueous spice extracts of garlic, pepper and turmeric. The antioxidant activity was performed using l,l-diphenyl-2-picryl- hydrazyl (DPPH) Radical Scavenging Method and the antimicrobial activity was evaluated by Disk Diffusion Assay. Phytochemical compounds tested were alkaloids, flavonoids, terpenoids, phenol and saponins. In decreasing order, the potency of the antioxidant activities showed Ascorbic acid > turmeric ethanol extract >pepper water extract> pepper ethanol extract> turmeric water extract> garlic ethanol extract> garlic water extract. The antimicrobial activity was highest in turmeric aqueous extract in terms of mean inhibition zone (7.5±2.10) against E. coli. The most effective treatment against B. subtilis was turmeric ethanol with highest mean inhibition zone (6.87±1.13). And for S. aureus, garlic ethanol extract has the highest mean inhibition zone (7.80±1.32). Phytochemical screening tests showed that in all treatments, the most abundant phytochemical were alkaloids and terpenoids. This study indicates that the spices like garlic, pepper and turmeric have antimicrobial and antioxidant activity.
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    Photodegradation of methylene blue in aqueous media using TIO2 -based heterogeneous photocatalysts under natural light
    Bernido, Julidyn P. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2015-06)
    This study developed two heterogeneous TiO2-based photocatalysts: pure TiO2 and Fe-doped TiO2 (Fe-TiO2). Heterogeneous catalysts were prepared by coating TiO2 and Fe-TiO2 powder on glass beads. The photocatalytic activity of both heterogeneous photocatalysts were studied by photodegradation of methylene blue in aqueous solution under two pH conditions (6 and 9) and two ionic concentration conditions (0 and 38 ppt). The Fe-TiO2 powder contained minimal amount (2.245%) of Fe as expected. However, surface functionality and ultraviolet-visible (UV-Vis) profile of both TiO2 and Fe-TiO2 powder were very similar indicating that doping did not alter these properties. Between the two heterogeneous catalysts prepared, the amount of Fe-TiO2 catalyst coated on glass beads was lower compared to pure TiO2. The removal of methylene blue was significantly affected by ionic concentration which removal is higher at lower ionic concentration (0 ppt). Although it appeared that the removal of methylene blue was higher at pH 9, statistical analyses revealed that the effect was not significant. In addition, the removal of methylene blue by the two catalysts were significantly different. Heterogeneous photocatalyst based on pure TiO2 showed higher removal of methylene blue in all pH and ionic concentration. Moreover, no interactive effects between variables were observed. Lastly, the blank showed no significant difference on the removal of methylene blue with the heterogeneous photocatalysts which suggest that degradation by direct photolysis from sunlight could be the reason for this result.
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    Smartphone-based colorimetric reader for phosphate analysis
    Acasio, Christian Jake M. (Division of Social Sciences, College of Arts and Sciences, University of the Philippines Visayas, 2017-06)
    A smartphone-based colorimetric reader (SBCR) was developed for the analysis of phosphate in water and soil. The developed smartphone-based colorimetric reader was designed to be portable and cost-effective tool for analysis of phosphates, thus help in addressing inaccessible laboratory-based analysis, as well as contribute to soil and water nutrient monitoring and management. The SBCR was composed of a colorimetric analyzer box, constructed from cardboards, a 96-well flat-bottom transparent microtiter plate that was used to hold the solutions and a bottom-based illumination was provided by a gadget. To help improve the performance of the SBCR, various physical factors were controlled. The focal length, the bottom illumination intensities and comparison of smartphones were all evaluated in order to determine at which conditions these operating parameters gave a better sensitivity. The operating parameters selected were 15 cm for the height between the smartphone and the 96-well MTP, 0% illumination setting, which was offered by the application software used to provide for the light from the gadget, and the usage of Phone A for the image acquisition of the analysis. The preliminaries gave a basis on the operating parameters used for the SBCR. For the phosphate analysis, the red channel was chosen for analysis of the image since at this channel the sensitivity was at the highest compared with the green and blue channels. The developed method was then evaluated for its analytical characteristics. It has a working range of 0.20-0.70ppm, LOD and LOQ of 0.06±0.18 ppm and 0.18±0.06 ppm, respectively, an intraday precision (%RSD) lower than 2% and inter-day precision of 1.46% (%RSD). In addition, the SBCR analysis application on water and soil samples showed no significant difference between the results from analysis done using the spectrophotometric method. The experimental results suggest that the SBCR method could be applied for phosphate analysis for both water and soil samples.