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Undergraduate Theses

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    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 methods
    Calawigan, 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.
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    Optimization of pretreatment process of lip gloss for the determination of lead by flame atomic absorption spectroscopy
    Bolivar, 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.
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    Determination of the concentration of essential minerals (Ca, Fe, K, Mg, Na, Zn) in honey samples from Negros Occidental
    Arellano, Lory Mae F. (Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, 2018-06)
    Honey is a natural, sweet and highly nutritional substance produced by bees through a series of nectar collection and chemical processes. Due to the popularity of the product, certain regions in the Philippines has been producing honey and recently, different apiaries from Negros Occidental has been producing its own share of popular product in the market. The products are well received by the consumers, but the problem is the lack of characterization which gives the product doubtful and unconfirmed nutritional value. This study focuses on the quantification of essential minerals (Ca, Fe, K, Mg, Na, Zn) present in local honey samples from Negros Occidental. Eight honey samples were obtained from the different apiaries including an external sample from Mindoro. Samples were acid digested using HNO3/H2O2 solution at 130 °C. The concentration of each minerals in the honey samples were analyzed using AAS. The data reported high concentration (5.71 to 93.20 ppm) of K on most of the samples. The second most abundant mineral in the local honey is Ca ranging from 13.67 to 45.88 ppm. The Mg concentration ranges from 1.19 to 4.09 ppm while Na is in between 0.82 to 3.14 ppm. The mineral Zn and Fe contained the lowest concentration in most of the samples with Zn at 0.46 to 0.86 ppm and Fe at 0.04 to 0.30 ppm.