단일입자 분석법을 이용한 potassium feldspar standard reference material의 정량분석

다국어 초록 (Multilingual Abstract)

A single particle analytical technique, named low-Z particle electron probe X-ray microanalysis (low-Z particle EPMA), employing an energy-dispersive X-ray detector with an ultra-thin window, was applied for the characterization of a potassium feldspar SRM sample (NIST SRM 70a). The low-Z particle EPMA technique allows the quantitative determination of low-Z elements such as C, N, and O as well. Thus many environmentally important particles containing low-Z elements, such as nitrates, sulfates, oxides, or mixtures including a carbon matrix, can be characterized. Eventually, the low-Z particle EPMA technique can provide size-segregated relative abundances (in number) of chemical species observed in aerosol samples. However, most aerosol analyses are done by the use of bulk analyses that provide data for mass concentrations of chemical elements, ions, and/or organic species. In this context, the number concentrations were converted to mass concentrations based on size, chemical compositions, and density of each particle which are obtainable from the low-Z particle EPMA. Since we know the chemical compositions of individual particles, the densities of the individual particles can be estimated. With the combination of information on chemical compositions, densities, and sizes of individual particles, mass fractions of chemical species have been obtained. The mass concentrations of major chemical elements in the SRM sample obtained from single particle analysis are very close to the certified values after the correction for charging effect which non-conducting potassium feldspar particles experienced. In addition, the low-Z particle EPMA technique can provide information on chemical compositions in terms of “molecular” concentrations, which can not be obtained by the use of bulk analysis and can be advantageous for environmental aerosol research.

목차 (Table of Contents)

• Ⅰ. ABSTRACT = 1
• Ⅱ. INTRODUCTION = 3
• Ⅲ. EXPERIMENTAL = 10
• 1. Sample description = 10
• 2. Preparation of Slide = 11
• 3. Collection and storage of sample = 12
• 4. X-ray data acquisition: = 13
• 5. Data Analysis = 16
• 5.1 Measurement of X-ray intensity = 16
• 5.2 Quantification of individual particle compositions = 21
• 5.3 Expert System = 26
• 5.3.1 Calculation of mass concentration = 34
• Ⅳ. RESULTS AND DISCUSSIONS = 40
• 1. Comparison of certified and SPA result before correcting the single particle analysis data for charging effect = 40
• 2. Comparison of SRM and SPA result after correcting the single particle analysis data for charging effect = 44
• 2.1 Charging effect = 44
• 2.2 Duane-Hunt Limit = 45
• 3. Mass fractions of molecular species = 50
• Ⅴ. CONCLUTIONS = 57
• Ⅵ. REFERENCES = 58
• Ⅶ. ACKNOWLEDGEMENTS = 62