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Worobiec, A.; Darchuk, L.; Brooker, A.; Potgieter, H.; Van Grieken, R. |
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Title |
Damage and molecular changes under a laser beam in SEM-EDX/MRS interface : a case study on iron-rich particles |
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A1 Journal article |
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Year  |
2011 |
Publication |
Journal of Raman spectroscopy |
Abbreviated Journal |
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Volume |
42 |
Issue |
4 |
Pages |
808-814 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
The control of damage to individual environmental particles by a laser beam during Raman spectroscopy carried out in ambient air is generally well understood. The nature and control of damage under vacuum conditions (e.g. in the scanning electron microscopy with energy X-ray detection combined with micro-Raman spectroscopyinterfaced SEM-EDX/MRS) are more complex and less well comprehended. The physical and chemical processes that affect the damage caused to small particles by lasers still remain somewhat unclear, but certainly the atmosphere (vacuum/air) and the beam intensity have very significant influences. Furthermore, it has been determined that some particles (e.g. haematite), although stable under an electron beam, are damaged by the laser beam, hampering their analysis. Additionally, when simultaneous analyses by SEM/EDX and MRS are considered, the correct choice of the collection surface plays a crucial role. As a result, the following collection substrates were tested to determine their influence on the laser beam damage process to the particle: silver and aluminium foils and silicon wafers. A test study was performed using artificial examples of haematite (Fe2O3) particles. Exposure of Fe2O3 particles in vacuum to 514- and 785-nm laser radiation often leads to their melting, transformation and evaporation. The dependence of the damage caused by the laser beam on the particle structure is reported here. Molecular and crystallographic changes have also been revealed. Formation of magnetite (as an effect of re-crystallisation) and Raman inactive structures was detected. |
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Wos |
000290484700033 |
Publication Date |
2010-09-27 |
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ISSN |
0377-0486 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:89518 |
Serial |
7751 |
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Author |
Worobiec, A.; Potgieter-Vermaak, S.; Brooker, A.; Darchuk, L.; Stefaniak, E.; Van Grieken, R. |
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Title |
Interfaced SEM/EDX and micro-Raman spectrometry for characterisation of heterogeneous environmental particles: fundamental and practical challenges |
Type |
A1 Journal article |
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Year |
2010 |
Publication |
Microchemical journal |
Abbreviated Journal |
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Volume |
94 |
Issue |
1 |
Pages |
65-72 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
The molecular character of atmospheric particulate matter is of prime importance when interpreting air pollution trends and its subsequent influence on environmental monitoring and preventative conservation. The known methods of estimating the molecular composition normally involve elemental analysis of particles (both as bulk and computer controlled analyses of single particles) with subsequent multivariate analyses to clusterise the elements in groups of elements that are closely related to each other. With this approach one can at best suggest associations. Evidently the application of molecular spectroscopy in addition to elemental concentration profiles would provide intimate information regarding the nature of the particles and consequently their fate. This paper gives an overview of research performed in our laboratory and describes the optimisation of experimental parameters to use scanning electron microscopy with energy-dispersive X-ray detection (SEM/EDX) or electron probe X-ray microanalysis (EPXMA) in parallel with micro-Raman Spectrometry (MRS) to investigate single environmental particles. The challenges associated with the two stand-alone techniques are revealed and consequently those posed with an interfaced approach are discussed. Preliminary results, of an initial investigation of the SEM/EDX interfaced with MRS to ultra-fine heterogeneous environmental particles, are given. |
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000273238800011 |
Publication Date |
2009-09-10 |
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0026-265x; 0026-265x |
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UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:79801 |
Serial |
8114 |
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Author |
de Maeyer-Worobiec, A.; Stefaniak, E.A.; Brooker, A.; Van Grieken, R. |
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Title |
Application of combined SEM/EDX and μ-Raman approaches for the chemical and structural characterisation of fine particulates |
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P3 Proceeding |
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Year |
2007 |
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P3 Proceeding; Laboratory Experimental Medicine and Pediatrics (LEMP); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Call Number |
UA @ admin @ c:irua:64633 |
Serial |
7470 |
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