| Summary: | 碩士 === 弘光科技大學 === 職業安全與防災研究所 === 96 === This thesis comprises two parts. The first part is to survey the environmental and biological monitoring finding from the exposure to metalworking fluids (MWFs) in an air-conditioner manufacturing plant is investigated. In this survey, all of the study subjects were exposed to metalworking fluids, and did not wear personal breathing protection. They were divided into two groups, those who were CNC press mechanists (n=6) and threading workers (n=11). Airborne samples in the breathing zones of workers were collected and analyzed. The subjects urinary metal levels include boron (B), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), silicon (Si) and zinc (Zn) were measured along with those of a control group. Results indicated the geometric mean (GM) concentrations of Cu, Fe, Mn, Si and Zn in these two exposed sites were higher than those measured in control group, illustrating that target elements originated mainly from occupational anthropogenic sources. Furthermore, this result were associated with the increased concentrations of metals Cu, Fe, Si, and Zn in used-MWFs. Biological levels of Si and Zn in urines of threading workers were significantly higher than of the control group. Concentrations of Cu, Fe and Zn in urines of CNC workers were significantly higher than of the control group.
With regard to the second part, supercritical carbon dioxide (scCO2) extraction is applied as an inherently safer and cleaner sample treatment method for identifying trace gallium in urine samples. Extraction was performed in the presence of a fluorinated ß-diketones chelating agent, 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3, 5-octanedione (HFOD), by unmodified scCO2. Quantitative extractions were conducted at 80°C and 20.7 MPa with 15 min static plus 15 min dynamic extractions, and were followed by analysis via graphite furnace atomic absorption spectroscopy (GFAAS). The proposed procedure was successfully applied to determine the concentrations of gallium in real urine samples spiked with various levels of gallium with satisfactory recoveries of 90.8-100.3% (n=6) and relative standard deviations < 10%. A standard reference material (SRM), Seronorm™ Trace Elements Urine, was used to validate the accuracy of the proposed method.
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