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Committee Member: search.filters.committeemember.Gamarcha, LeandroDepartment: search.filters.department.College of Arts and Sciences

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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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    Heavy metals (Cr, Cu, Pb, and Zn) concentrations of road-deposited sediments within six public plazas in Iloilo City
    Caceres, 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.