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UPV Theses and Dissertations

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    Fourier transform -infrared-attenuated total reflectance spectroscopy in conjunction with the principal component analysis and agglomerative hierarchical clustering to classify virgin coconut oil and other edible oils
    Aloba, Eugene J. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2006-04)
    This work investigates the potential of Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) Spectroscopy in conjunction with Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC) to classify virgin coconut oil (VCO) from other different edible oils in the test set. Among the PCA types, Pearson produced the best biplot graphs that showed both the separation of VCO and coconut oil (only in one group) from other oils, and the separation of VCO and coconut oil (CCO) into two distinct groups using the fingerprint region of the spectra. Kendall dissimilarity/Ward’s method successfully clustered VCO and CCO as separate classes using the same region of the spectra. These results showed that the highest percent variability in the spectra of different oils occurs in the fingerprint region, and hence where spectroscopic classification of oils can be performed best.
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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.
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    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.