Ultratrace speciation of nitrogen compounds in aerosols collected on silicon wafer surfaces by means of TXRF-NEXAFS

2004 ◽  
Vol 19 (1) ◽  
pp. 81-86 ◽  
Author(s):  
S. Török ◽  
J. Osán ◽  
B. Beckhoff ◽  
G. Ulm
Keyword(s):  
Silicon Wafer ◽  
Detection Limits ◽  
Fluorescence Analysis ◽  
Nitrogen Compounds ◽  
Undulator Radiation ◽  
X Ray ◽  
Acceptable Accuracy ◽  
Rural Aerosols ◽  
X Ray Absorption ◽  
Wafer Surfaces

Total reflection X-ray fluorescence analysis (TXRF) using monochromatized undulator radiation in the PTB radiometry laboratory at the synchrotron radiation facility BESSY II has been employed to investigate the chemical state of nitrogen compounds in aerosols. The aerosol samples of different size fractions were deposited on silicon wafer surfaces in a May impactor. Using a thin window Si(Li) detector, TXRF detection limits for nitrogen are in the upper fg and lower pg range. Taking advantage of the tunability of monochromatized undulator radiation, the near edge X-ray absorption fine structure (NEXAFS) could be combined with TXRF analysis, allowing for the speciation of the aerosols at the nitrogen K absorption edge. Such low detection limits enable an analysis of aerosol samples taken in 10 min with acceptable accuracy. Applicability of the technique to real aerosol samples has been used to compare nitrogen oxidation state in suburban and rural aerosols

scholarly journals Analysis of individual microscopic particles by means of synchrotron radiation induced x-ray micro fluorescence

1992 ◽  
Vol 50 (2) ◽  
pp. 1766-1767
Author(s):  
K. Janssens ◽  
F. Adams ◽  
M.L. Rivers ◽  
K.W. Jones
Keyword(s):  
Synchrotron Radiation ◽  
Detection Limits ◽  
Fluorescence Analysis ◽  
Individual Particle ◽  
Quantitative Character ◽  
Particle Analysis ◽  
X Ray ◽  
Interesting Approach ◽  
Radiation Induced ◽  
Backscattered Electron

Micro-SXRF (Synchrotron X-ray Fluorescence) or micro-SRIXE (Synchrotron Radiation Induced X-ray Emission) is a microanalytical technique which combines the sensitivity of more conventional microchemical methods such as Secondary Ion Microscopy (SIMS) and μ-PIXE (Proton Induced X-ray Emission) with the non-destructive and quantitative character of X-ray fluorescence analysis. The detection limits attainable at current SXRF-facilities are situated in the ppm (and in favourable cases the sub-ppm) range. The sensitivity of SRIXE can be used advantageously in individual particle analysis. This type of analysis is used, e.g., for studying sources of athmospheric pollution. Analysis of standard NIST micro-spheres at the NSLS-SRIXE facility yielded minimum detection limits in the 1 to 100 ppm range for particle sizes of around 10 to 30 μm.An interesting approach to individual particle characterisation is by means of electron microprobe analysis (EPMA). By using the backscattered electron signals, in an automated fashion, particles can be easily located on a filter substrate and their size and shape determined.

Filter Absorption Correction for X-Ray Fluorescence Analysis of Aerosol Loaded Filters

1975 ◽  
Vol 19 ◽  
pp. 339-353
Author(s):  
R. E. Van Grieken ◽  
F. C. Adams
Keyword(s):  
Particulate Matter ◽  
Fluorescence Analysis ◽  
Filter Material ◽  
Back Side ◽  
Absorption Effect ◽  
X Ray ◽  
Absorption Correction ◽  
Loaded Side ◽  
X Ray Absorption

In the case of X-ray fluorescence analysis of aerosol loaded filters, the X-ray absorption effect Is due to particulate matter absorption and to filter material absorption. The latter contribution is of a predominant importance in many practical cases. It can be calculated from the ratio of the X-ray intensities measured from the front and back side of the filters. The sandwich geometry obtained by folding the filters in two with the loaded side inwards during the measurement renders the filter material absorption correction much simpler and often more accurate, and offers distinct additional advantages.

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