Microdistributional analysis

Particle-induced XRF (PIXE) has many advantages over conventional XRF. Irradiations are performed in ion accelarators (Muminov and Haidarov, 1980). It ensures up to 100 times better detection limits and values of 0.1-1 mg/kg can be obtained even in routine analysis. Accuracy and precision normally lie in the 1-5% range. The proton beam can be focused to a extremely small spot (d I p.m) which permits microdistribution analysis of elements with Z = 25 80. In this interval lies the best sensitivity... 

Every effort is made here to achieve the highest possible absolute power of detection. Microdistribution analysis represents the primary field of application for microprobe techniques based on beams of laser photons, electrons, or ions, including electron microprobe analysis (EPMA), electron energy-loss spectrometry (EELS), particle-induced X-ray spectrometry (PIXE), secondary ion mass spectrometry (SIMS), and laser vaporization (laser ablation). These are exploited in conjunction with optical atomic emission spectrometry and mass spectrometry, as well as various forms of laser spectrometry that are still under development, such as laser atomic ab.sorption spectrometry (LAAS), resonance ionization spectrometry (RIS). resonance ionization mass spectrometry (RIMS), laser-enhanced ionization (LEI) spectrometry, and laser-induced fluorescence (LIF) spectrometry [36]-[44],... 

Surface analysis is in turn a specialized form of microdistribution analysis, one that provides information on the coverage, distribution, and content of components either at the surface of a solid or in discrete layers located near the surface. Elemental... 

Nakamura T., NagaoK., andTakaokaN. (1999) Microdistribution of primordial noble gases in CM chondrites determined by in situ laser microprobe analysis decipherment of nebular processes. Geochim. Cosmochim. Acta 63, 241-255. 

Study of the metal microdistribution in CCA treated wood and its pyrolysis residue by energy dispersive X-ray analysis coupled to scanning electron microscopy (SEM-EDXA),... 

Helsen L. and Van den Buick E. (1998) The Microdistribution of Copper, Chromium and Arsenic in CCA Treated Wood and Its Pyrolysis Residue Using Energy Dispersive X-Ray Analysis in Scanning Electron Microscopy. Hoizforschung, 52 (6), 607-614. 

PIXE. Proton-induced x-ray emission (PIXE) is a relatively nondestructive technique with detection limits in the parts per million range (Torok and Van Grieken 1994). It has been used in studies of the microdistribution of toxic metals (e.g., lead) in thin-sliced sections of tissues (Lindh et al. 1978 Lowe et al. 1993 Schidlovsky et al. 1990). The simultaneous quantification of a large number of elements in a sample makes PIXE an important analytical tool for use in diverse toxicological studies (Johansson and Campbell 1988). Those applications were recently discussed in a report on elemental analysis of renal slices (Lowe et al. 1993). However, the shallow sampling depth (tens of microns) of the proton beam restricts applications of PIXE to measurements of surface distributions. 

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