Undergraduate Theses
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Item Removal of total solids from surface water of Malihao River, Victorias, Negros Occidental using chitosan derived from green mussel (Perna viridis) shellCaligan, Jeff Tristan Z. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)Total solids are water pollutants that can either be suspended or dissolved in water. Suspended solids are those that can be filtered while those that can passed through are considered as dissolved solids. Five sampling stations were tested along Malihao River in Victorias City, Negros Occidental to determine parameters such as pH, temperature, total settleable solids (TSeS), total suspended solids (TSS), total dissolved solids (TDS), volatile suspended solids (VSS), conductivity, and salinity. Among these parameters, the focus of the study is on TSS and TDS and assess the removal efficiency of chitosan with these pollutants. The chitosan used was obtained from the shells of green mussel (Perna viridis) through deacetylation of chitin. The chitosan obtained has 73% degree of deacetylation and has characteristic peaks in the IR spectra at 3470.82 cm-1 and 1636.36 cm-1 representing the vibrating aliphatic O-H and bending N-H group, respectively. The optimum chitosan dosage was determined at 15 mg, which has removal efficiency of 83.46% and 25.48% for TSS and TDS, respectively. It also decreases the turbidity of the water based on the clarity in color. High TSS values were observed at Station 2 (Malihao Bridge) and Station 5 (Daan Banwa Wharf) with values of 125.5 and 232.0 mg/L, respectively. These values exceed the DENR Administrative Order 2016-08 for Class C waters, which is 80 mg/L. The optimum dosage was used to remove TSS and TDS at each sampling stations. TSS of all sampling stations were reduced to more that 50% of the initial value while TDS values rose to 80% and higher of the initial value. Thus, chitosan derived from green mussel shells were effective in removal of TSS but not with TDS.Item Determination of instrument detection limit and method detection limit of Varian 55B flame atomic absorption spectrometer for cadmium, chromium, copper, iron, lead, manganese and zinc using sips-10 and manual sample introduction methodsCalawigan, Roland Joseph C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2009-04)Determination of detection limits is an essential measure of performance for a quantitative laboratory, method or analyst. In this study, the Instrument Detection Limit (IDL) and Method Detection Limit (MDL) of F-AAS Varian 55B for cadmium, chromium, copper, iron, lead, manganese and zinc were determined using the SIPS-10 and manual sample introduction methods. For IDL determinations, EPA’s SW-846 method (Test Methods for Evaluating Solid Waste and Physical/Chemical Methods) was employed for both sample introduction methods where deionized water was analyzed for twenty times for three non-consecutive days. MDL determinations were done based on the definition given by the United States Code of Federal Regulations (40 CFR part 136, Appendix B - Definition and Procedure for the Determination of the Method Detection Limit). In this procedure, MDLs were estimated by calculating the standard deviation from the analysis of a standard solution containing the analyte with a concentration determined from the estimated detection limit, which was also analyzed for twenty times. Results showed that for the determination of IDL, all of the elements have lower values (Cd 0.000887 mg/L, Cr 0.00435 mg/L, Cu 0.000128 mg/L, Fe 0.000816 mg/L, Pb 0.000742 mg/L, Mn 0.000985 mg/L, Zn 0.000585 mg/L) for the manual method than the SIPS-10 method (Cd 0.00399 mg/L, Cr 0.0150 mg/L, Cu 0.00222 mg/L, Fe 0.00913 mg/L, Pb 0.0217 mg/L, Mn 0.00132 mg/L, Zn 0.00445 mg/L). For MDL, the results showed variations for both the two sample introduction methods. The MDL values for cadmium, chromium, copper, iron, lead, manganese and zinc are 0.0374 mg/L, 0.0235 mg/L, 0.00203 mg/L, 0.0197 mg/L, 0.0805 mg/L, 0.00325 mg/L and 0.00686 mg/L in the manual method, respectively and 0.0101 mg/L, 0.0429 mg/L, 0.00280 mg/L, 0.0186 mg/L, 0.19 7 mg/L, 0.00312 mg/L and 0.0103 mg/L in the SIPS-10 method, respectively. Both methods have comparable precision for copper, iron, manganese and zinc determinations while SIPS-10 method is more precise for cadmium, chromium, and lead analysis.Item Comparative study of trace metals and common impurities of table salt produced in Leganes, Iloilo and Tibiao, AntiqueCalawag, Jerolet E. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2000-10)Trace metals such as cadmium (Cd), chromium (Cr) and lead (Pb) as well as the common impurities in salt like magnesium (Mg), calcium (Ca), sulfate, moisture, matter insoluble in water (MIW) and matter insoluble in acid (MIA) were analyzed using spectrophotometric (Flame Atomic Absorption &UV-vis Spectrophotometers) and gravimetric methods. Results showed that percentage concentrations of magnesium and calcium were significantly higher in sample A (Tibiao table salt) than in sample B (Leganes table salt) at 1- percent level of confidence. The percentage concentrations of MIW, MIA, moisture and sulfate were significantly higher in sample B than in sample A. Results of Uv-vis absorption spectroscopy indicated that both chromium and cadmium were absent in both samples while the lead concentrations in samples A and B were 10.9190 and 11.4831 ppm respectively. At 5% level of probability, the lead concentrations of both samples did not differ from each other. Using another technique of analyzing trace metals, the flame atomic absorption spectroscopy based on flame atomization, different results were obtained. Lead concentration in samples A and B were 6.4874 and 9.4977-ppm salt respectively. At 5 % level of probability, sample B had higher lead concentration than in sample A. The lead concentrations in both samples were all higher than 0.015 ppm, the allowable maximum limit of lead in water, or any drinks. The over-all results showed that sample B had higher contaminants than in sample A.Item Sediment organic matter, nitrogen, and phosphorus of four tivers in Miagao, IloiloCahilig, Guen Gian D. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2019-06)The four rivers of Miagao are examples of aquatic areas where sediment pollution can be related and mostly caused by anthropogenic and non-point sources. The four rivers of Miagao, namely Bacauan, Naulid, Oyungan and Tumagbok rivers, were assessed and observed to have low levels of water due to the dry season, presence of water stagnation due to dikes; other factors such as discharges from domestic activities and livestock wastes, and thick vegetation are also present in the river. The relevance of this study is to provide baseline information about the levels of organic matter, NH4-N, and available phosphorus present in the river, provide public knowledge about the negative impacts of excessive levels of those parameters; and locate possible sources of the pollution through the values obtained. For the total phosphorus concentration present in river sediments, the values are ranging from 0.0648 ppm to 0.154 ppm. Therefore, the values of the available phosphorus are harmful and can cause eutrophication to the river. However, for the values of organic matter and nitrogen, it was reported to be not harmful to the river but can still contribute to the excessive nutrient levels and eutrophication of the river.Item A preliminary study on the average yield of crude capsaicin from common varieties of Capsicum frutescens L. at two stages (Young and mature) using three extracting solventCadornigara, Ma. Sylvia C. (Division of Physical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 1998)Crude capsaicin content of the air dried and homogenized plant material of the three varieties of Capsicum frutescens L. namely cayenne, tobasco and ‘kitikot’ were determined using diethyl ether, 99.5 % ethanol and 1.0N NaOH as extracting reagents. Statistical analysis showed no significant difference on the average percent yield of crude capsaicin on the three varieties of Capsicum frutescens L. using similar extracting solvent, but a significantly higher yield of crude capsaicin was found with 99.5% ethanol and 1.0N NaOH. Through thin layer chromatography the major components of the extracts identified could probably be capsaicinoids (Rf 15-17), carotenoids (only in 99.5% ethanol, Rf 96-97), and capsanthin (Rf 27-29) using n-hexane-acetone.Item Spontaneous formation of silver nanoparticles in humid acid-rich water of Santa Barbara, IloiloCadelina, Mary Dored Ann D. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)Humic acid (HA) - rich water of Sta. Barbara, Iloilo is successful in acting as a reducing and capping agent in the synthesis of silver nanoparticles (AgNPs). UV-Visible spectroscopy was used to determine the effect of irradiation time, varying HA and AgNO3 concentration, and electrolyte addition. Furthermore, the bactericidal efficacy of AgNPs was evaluated using broth microdilution method. Measurement of AgNPs was done using transmission electron microscopy (TEM). Lower irradiation time (10- 40 min) shows an increasing absorbance trend. However, absorbance decreased and showed bathochromic shifts when irradiated at longer times (50-60 min). AgNP formulations of 40 ppm HA with 4 mM AgNO3 and 50 ppm HA with 4 mM AgNO3 showed the highest peak intensity for varying AgNO3 and HA concentration, respectively. These results were found in both irradiated and un-irradiated samples. Aggregation occurred upon the addition of 50 mM, 100 mM, and 500 mM NaCl but was more prominent at 500 mM NaCl. Dialyzed and un-dialyzed AgNPs have bactericidal activity. However, un-dialyzed AgNP was a more effective treatment because it showed a bactericidal activity up to 1:16 dilution for both Staphylococcus aureus and Escherichia coli as compared to the dialyzed AgNPs which showed a bactericidal activity up to 1:4 for S. aureus and 1:8 for E. coli. The dialyzed AgNPs are polydispersed but were mostly small with sizes less than 10 nm based on the TEM image.Item Heavy metals (Cr, Cu, Pb, and Zn) concentrations of road-deposited sediments within six public plazas in Iloilo CityCaceres, Rizza Daphet E. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2011-04)Contamination from overland transportation is an unavoidable result of urbanization. Cr, Cu, Pb, and Zn arc common heavy metals introduced to the environment by transportation. Road-deposited sediment (RDS) samples were collected from six public plazas (Villa Plaza, Molo Plaza, Mandurriao Plaza, Plaza Libertad, Lapaz Plaza and Jaro Plaza) in Iloilo City from March 2010 to May 2010. 0.5M HC1 was used as extractant and heavy metals (Cr, Cu, Pb, and Zn) concentrations were determined using Flame Atomic Absorption Spectrophotometer (FAAS). The mean concentrations of Cr, Cu, Pb, and Zn in road-deposited sediments from six plazas were 8.79 ± 1.93, 40.90 ± 24.21, 60.74 ± 22.32, and 164.25 ± 25.0 mg/kg, respectively. Metal enrichment of Cr, Cu, Pb and Zn were approximately xl, x8, x7 and x18 more than the background values respectively. There was no significant temporal variation in metals concentrations of RDS between sampling collections. Generally, RDS from Plaza Libertad has the highest metal concentrations. Cu and Pb metals were highly correlated (R2 = 0.891) indicating possible similar sources. A good correlation (R2 = 0.918) was observed between Pb concentration and the number of vehicles that pass along the plaza per hour. Heavy metal concentrations in sediments from plazas have low hazard quotients but bioaccumulation of metals in the body could cause health effects. Efficiency of digestion procedures varied depending on characteristics, texture and composition of road-deposited sediments. 0.5M HC1 digestion was used because it is simple, cost-effective, time-efficient and it leaches out meaningful amounts of bioavailable metals. Using HC1 as extractant simulates human digestion since human stomach contains HC1 that could leach out metals if road-deposited sediments were ingested.Item Microwave-assisted extraction of sulfated polysaccharide (Fucoidan) from Sargassum oligocystum MontagneCaceres, Kristhia Loren Maree R. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2016-06)Algae have been a source of food and medicine for humans. It contains sulfated polysaccharides that have been used as drugs. Fucoidan, a sulfated polysaccharide, found in brown algae have received more attention in recent years due to its potential biological properties that are important in cosmetics, pharmaceuticals and health industries. Fucoidan was recovered from brown seaweed Sargassum oligocystum Montagne by microwave - assisted extraction (MAE) technology. Different conditions of extraction time (10, 15 and 20 min) at 0.150kW were evaluated and the optimal fucoidan yield was 1.255 ± 0.0068 %, obtained at 20 minutes. Using this condition, a different set of samples was subjected to hot water extraction (HWE) and the average yield was 0.9767 ± 0.0002 %. The extracts from both methods were subjected to physico-chemical tests like gelling temperature, melting temperature, FTIR analysis, total carbohydrate content and total sulfate content. Having gelling and melting temperature values of 32 "C and 91"C for MA extracts and 30 "C and 89 °C for HW extracts showed qualities of a good agar gel. The total carbohydrate contents were 75.31 ± 0.015 % and 74.06 ± 0.0113 %, for MAE and HWE, respectively. It was also observed that the sulfate content of extracted fucoidan decreased with increasing extraction time. This study shows that MAE is an efficient technology to recover fucoidan from Sargassum oligocystum Montagne compared with the conventional heating method. This method provided enhanced extraction efficiency at reduced process time.Item Antidiarrheal activity of Pterocarpus indicus bark extracts using castor oil-induced diarrhea model on miceCabatea, Norberto C. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2010-04)This study evaluated the antidiarrheal activity of the bark of Pterocarpus indicus (Narra). The crude methanolic extract of the bark was subjected to sequential extraction using hexane, DCM, and ethyl acetate. These extracts were tested for antidiarrheal activity in vitro using the castor oil induced diarrhea model in mice employing charcoal tracing method. Thin Layer Chromatography (TLC) was used in determining the chemical constituents present in every extracts using spraying reagents to aid in the visualization of spots. Crude methanolic extract dosage 200 mg/kg body weight is the comparable dosage to the reference drug loperamide (2 mg/kg body weight). The hexane extract was the most active fraction and 200 mg/kg dosage was more effective than with the positive control loperamide (2 mg/kg). No antidiarrheal activity found in the fraction of DCM and ethyl acetate extracts. Phytochemical screening revealed positive tests for tannins, phenolics, terpenes, cardiac glycosides, saponins and reducing sugars in all fractions. Tests for flavonoids and alkaloids, however, were negative.Item In vitro antibacterial activity of Hibiscus rosa sinensis leaf extracts against some pathogens associated with urinary tract infectionsCabayao, Coney B. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2011-04)The in vitro antibacterial activity of Hibiscus rosa sinensis leaf ( methanolic, dichloromethane, ethyl acetate, n-hexane, and aqueous ) extracts were studied against Gram-negative (Escherichia coli and Pseudomonas aeruginosa ) and Gram-positive ( Streptococcus faecalis) bacteria. The methanolic extract was subjected to sequential liquid-liquid extraction using solvents of varying polarity and concentrations. Out of the 5 extracts, methanolic and dichloromethane extracts exhibited the highest antibacterial activity as measured using the zone of inhibition. This was followed by ethyl acetate and n-hexane extracts. At 200 mg/ml concentration, all extracts were considered active when tested with E. coli and S. faecalis, and were partially active against P. aeruginosa. The aqueous extract was inactive towards the three bacteria. The 200 mg/ml concentration showed no significant difference when compared with the positive control, amoxicillin (12.51μg/ml). This shows that Hibiscus rosa sinensis exhibits a promising antibacterial activity. Phytochemical analysis of the active fraction- the methanolic extract- showed the presence of alkaloids, tannins, glycosides, saponins, steroids, flavonoids, terpenoids, and anthraquinones. These bioactive components could be responsible for the antibacterial activity of Hibiscus rosa sinensis leaf extracts.