EPXMA electron probe X-ray Microanalysis

The primary methods of analyzing for lead in environmental samples are AAS, GFAAS, ASV, ICP/AES, and XRFS (Lima et al. 1995). Less commonly employed techniques include ICP/MS, gas chromato-graphy/photoionization detector (GC/PID), IDMS, DPASV, electron probe X-ray microanalysis (EPXMA), and laser microprobe mass analysis (LAMMA). The use of ICP/MS will become more routine in the future because of the sensitivity and specificity of the technique. ICP/MS is generally 3 orders of magnitude more sensitive than ICP/AES (Al-Rashdan et al. 1991). Chromatography (GC,... 

X-ray microanalysis techniques— in particular, electron probe x-ray microanalysis (EPXMA or EPMA) and SEM coupled with energy dispersive spectrometers (EDS, EDX) are, by far, one of the surface analysis techniques most extensively used in the field of art and art conservation, and they have actually become routine methods of analyzing art and archaeological objects and monitoring conservation treatments [34, 61, 63]. 

High-resolution compositional measurements are possible through use of a variety of microanalytical methods. Ideally, these should be non-destructive, can be targeted on small areas of sample, and have low minimum detection limits. Electron-probe X-ray microanalysis (EPXMA) and proton-induced X-ray emission (PIXE) techniques have both been used successfully on archaeological sediment thin sections (19, 20). Both techniques yield elemental composition data for a range of elements. EPXMA has the advantage of being nondestructive, whereas PIXE when used on thin-section samples is typically destructive conversely the detection limit for PIXE is lower than EPXMA. 

The particles were deposited on the slides by in5>actation, sedimentation and diffusion. Subsequently, the samples were analyzed by scanning electron microscopy (SEM). Information on morphology and size distribution was obtained from image analysis, while the elemental composition of particles was determined by electron probe X-ray microanalysis (EPXMA). 

Optical microscopy (OM), polarized light microscopy (PLM), phase contrast microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM) are the methods normally used for identification and quantification of the trace amounts of asbestos fibers that are encountered in the environment and lung tissue. Energy-dispersive X-ray spectrometry (EDXS) is used in both SEM and TEM for chemical analysis of individual particles, while selected-area electron diffraction (SAED) pattern analysis in TEM can provide details of the cell unit of individual particles of mass down to 10 g. It helps to differentiate between antigorite and chrysotile. Secondary ion mass spectrometry, laser microprobe mass spectrometry (EMMS), electron probe X-ray microanalysis (EPXMA), and X-ray photoelectron spectroscopy (XPS) are also analytical techniques used for asbestos chemical characterization. 

Material properties often depend on the constituents of inclusions as small as a few micrometers large or surface layers with a thickness of 0.1-100 nm. From the 1970s onward, microanalysis has become a major challenge. Initial methods such as electron probe X-ray microanalysis (EPXMA) or dynamic secondary ion mass spectrometry (SIMS) determine elements at the microscopic scale, but charge buildup and beam-induced sample damage hamper their application to nonconducting organic materials. 

The earliest commercially available X-ray spectrometer appeared on the market in 1938. Ten years later, Friedman and Birks built the prototype of the first commercial X-ray secondary emission instrument. Somewhat later, Castaing and Guinier built the first electron probe microanalyzer using a focused electron beam to induce X-ray emission of the elements present in microscopic samples using electron probe X-ray microanalysis (EPXMA). The use of protons in PIXE for chemical analysis was first demonstrated by Sterk in 1964. From the 1960s until the present day, the use of large-particle accelerators (synchrotron rings) has resulted in a dramatic... 

Because the mechanical requirements of the ED detection geometry are moderate in comparison to the WD equivalent, in the more recently developed analogs or variants of the XRE method solid-state detectors are almost exclusively employed. Such related methods are electron probe X-ray microanalysis (EPXMA) and (microscopic) proton-induced X-ray emission (/r-PIXE). It should be noted, however, that many EPXMA instruments are also equipped with WD detectors (e.g., for low-Z element analysis). Important variants of the conventional XRF technique that have achieved... 

Many interesting studies have been published on the effects of a polluted atmosphere on stone with emphasis on the more chemical aspects [39,40,41]. The physical-chemical analytical techniques employed in the study of building materials provide very accurate qualitative and quantitative results on the alterations related to the patina or crust as well as the bulk chemistry of the exposed stone. Scanning electron microscopy (SEM), Electron probe X-ray microanalysis (EPXMA), Fourier-transform infrared analysis (FTIR), X-Ray diffraction (XRD), energy dispersive X-Ray fluorescence, Ion Chromatography, are the most used techniques for the studies of sulphate black crusts as well as to evaluate the effect of exposition time of the sample stone to weathering[42,43]. 

EM PA (electron microprobe analysis) EPXMA (electron probe X-ray microanalysis)... 

Routine inorganic elemental analysis is carried out nowadays mainly by atomic spectrometric techniques based on measurement of the energy of photons. The most frequently used photons for analytical atomic spectrometry extend from the ultraviolet (UV 190-390 nm) to the visible (Vis 390-750 nm) regions. Here the analyte must be in the form of atoms in gas phase so that the photons interact easily with valence electrons. It is worth noting that techniques based on the measurement of X-rays emitted after excitation of the sample with X-rays i.e. X-ray fluorescence or XRF) or with energetic electrons (electron-probe X-ray microanalysis or EPXMA) yield elemental information directly from solid samples, but they will not be explained here instead they will be briefly treated in Section 1.5. 

EPXMA electron-probe x-ray microanalysis HG hydride generation... 

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