Undergraduate Theses
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14583/13
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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 Optimization of pretreatment process of lip gloss for the determination of lead by flame atomic absorption spectroscopyBolivar, Eduardo L., Jr. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2013-10)The optimization of the pretreatment process for the analysis of lead in lip gloss using a flame atomic absorption spectrophotometer (FAAS) was proposed in this study. Two variables were tested for this study: volume of nitric acid, HNO3 and volume of hydrogen peroxide, H202. Results of the optimization and statistical analysis revealed that 47.3 mL HNO3 and 2 mL HNO3 were the optimum volumes suited for the digestion of lip gloss in obtaining high analytical results for the lead analysis. Five different samples were randomly purchased from local markets in Iloilo City that may contain high levels of lead due to a report from BFAD that warned people about the use of several lipsticks imported abroad. Lip gloss samples were analyzed using the optimized protocol. The heavy metal content in the lip gloss samples were found to be between 52.0 - 126.3 mg lead/kg of sample. Results show that these were slightly higher than the allowable limits for lead contents in lip gloss set by BFAD and WHO. One-way ANOVA statistics showed that there was a significant difference in the lead contents among the different lip gloss samples.Item Bioaccumulation of cadmium, copper and lead by Hydrilla (Hydrilla vericillata)Baniago, Arjay C. (Division of Pysical Sciences and Mathematics, College of Arts and Sciences, University of the Philippines Visayas, 2007-04)Bioaccumulation of cadmium, copper, and lead by Hydrilla (Hydrilla verticillata) were tested to 5 different initial concentrations. The water contaminant sample was composed of mixed cadmium, copper and lead metals supplied as nitrate salts. These were analyzed for the decrease in concentrations at 24-hour intervals for 5 days using the SpectrAA 55B Atomic Absorption Spectrometer. Plants exposed only for 5 days were digested and analyzed. The plant growth was normal at lower concentrations and showed higher removal efficiency. H. verticillata showed maximum removal percentage on the 5th day of exposure at 5 mg L-1 for cadmium (90.47%) and copper (95.20%) but for lead was on the 1st day (96.74%). The order of metal ion removal and the actual uptake for the three metals by H. verticillata is Pb>Cu>Cd, but at lower concentration, cadmium was absorbed more than copper. The copper and lead uptakes by H. verticillata are superior as compared to other aquatic plants uptakes. Lead uptake at higher concentrations might be due to physicochemical adsorption of the metal to the plant components and not on metabolism-mediated uptake, because plant condition does not have an adverse effect on the uptakeItem Optimization of lead (II) adsorption of EDTA-functionalized magnetic graphene oxide using response surface methodologyAngeles, 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)%.