X-rays spectrometry

Modem trace analysis is interested in detailed information about the distribution of elements in microareas and their chemical binding forms (specia-tion). The limited sample mass implies methods with absolute detection limits as high as possible. Use of the sputtering process as a sampling technique localises the analytical zone at the outer layers of a solid, and allows analysis to progress into the interior. 

Solid and slurry sampling using the graphite furnace have been reviewed [220,221]. A monograph dealing with solid sample analysis is available [222]. 

Applications Specific applications of the direct spectrometric analysis methods of solid samples of Table 8.36 are given under the specific headings. One investigation that is practically only possible by direct solids analysis is checking the homogeneity of polymers [136,137] this is of significance for reference materials and for quality control. A method for the assessment of microhomogeneity should meet various requirements [223]  

Obviously, direct SS-GF-ZAAS fulfils these criteria. A carefully performed homogeneity study using SS-GF-ZAAS was reported for the VDA CRMs (Cd in polyethylene) [137,223,224]. Solid sampling also allows analysis of high-purity materials (blank-free, low limits of analysis). 

Rtihl [141] has reported on very large scale SS-GFAAS and XRF analysis of Cd in polymers for product control purposes in the automobile industry (approximately 20 000 parts per year) as a reaction on a Swedish law for environmental protection (upper limit of 75ppm). Another sample of direct SS-GFAAS in industry is the control of all raw materials, processing steps, and products for adhesive tapes for the content of Cu, Mn, Fe, Cd and Pb, which act as a rubber poison by catalytic effects [144]. 

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The section on Spectroscopy has been retained but with some revisions and expansion. The section includes ultraviolet-visible spectroscopy, fluorescence, infrared and Raman spectroscopy, and X-ray spectrometry. Detection limits are listed for the elements when using flame emission, flame atomic absorption, electrothermal atomic absorption, argon induction coupled plasma, and flame atomic fluorescence. Nuclear magnetic resonance embraces tables for the nuclear properties of the elements, proton chemical shifts and coupling constants, and similar material for carbon-13, boron-11, nitrogen-15, fluorine-19, silicon-19, and phosphoms-31. 

Figure 8.30 K emission spectrum of tin. The ] and P2 lines are at 0.491 A and 0.426 A, respectively. (Reproduced, with permission, from Jenkins, R., An Introduction to X-ray Spectrometry, p. 22, Hey den, London, 1976)...

R. E. Van Grieken and A. A. Markowicz, Handbook of X-ray Spectrometry, Methods and Techniques, Marcel Dekker, Inc., New York, 1993. 

POSSIBILITY OF USING GRASING EMISSION IN WAVE DISPERSION X-RAY SPECTROMETRIES... 

THE POTENTIAL OF TOTAL REFLECTION X-RAY SPECTROMETRY FOR STUDY OF THE BLOOD SERUM... 

The electron-optical performance of the EPMA system is indistinguishable from that of a conventional scanning electron microscope (SEM) thus, EPMA combines all of the imaging capabilities of a SEM with quantitative elemental analysis using both energy- and wavelength-dispersive X-ray spectrometry. ... 

The principle application of XRF thin-film analysis is in the simultaneous determination of composition and thickness. The technique has been used for the routine analysis of single-layer films since 1977 and multiple-layer films since 1986. Two main sources of publications in the fields are the annual volumes of Advances in X-Ray Analysis by Plenum Press, New York, and the Journal of X-Ray Spectrometry by Heyden and Sons, London. Typical examples on the analysis of single-layer films and multiple-layer films are used to illustrate the capabilities of the technique. 

Although XRF is generally the X-ray spectrometry method of choice for analysis of major and trace elements in bulk specimens, useful PIXE measurements can be made. A detailed review of the main considerations for thick-target PEXE provides guidance for trace analysis with known and unknown matrices and bulk analysis when the constituents are unknown. Campbell and Cookson also discuss the increased importance of secondary fluorescence and geometrical accuracy for bulk measurements. 

Another application involves the measurement of copper via the radioisotope Cu (12.6-hour half-life). Since Cu decays by electron capture to Ni ( Cu Ni), a necessary consequence is the emission of X rays from Ni at 7.5 keV. By using X-ray spectrometry following irradiation, sensitive Cu analysis can be accomplished. Because of the short range of the low-energy X rays, near-surface analytical data are obtained without chemical etching. A combination of neutron activation with X-ray spectrometry also can be applied to other elements, such as Zn and Ge. 

In X-ray spectrometry, attenuation, deflection and interference must be considered. Attenuation is described by the well-known Lambert-Beer law and the mass attenuation coefficient as given for conventional XRF. 

K. L. Williams An Introduction to X-Ray Spectrometry, AUen and Unwin, London 1987. 

The composition of steels or other metals is commonly analyzed by emission or X-ray spectrometry during and after the production process. Both methods have to be calibrated by solid samples. These are either exactly analyzed samples taken from the same process or synthetic melted mixtures of the matrix with added accompanying elements (RMs). Available CRMs are then used to control the slope of the calibration function. Today, available RMs and CRMs are increasingly and exclusively used in spectral laboratories as the chemical analysis became much restricted and typical control laboratories were totally closed (Slickers 1993). 

X-ray spectrometry is regularly being reviewed [225, 226]. An overview of X-ray techniques is available [227]. A handbook of X-ray spectrometry has appeared [228]. XRS techniques generate some 5000 literature references yearly. 

K. Tsuji, R. van Grieken and J. Injuk (eds), X-Ray Spectrometry. Recent Technological Advances, John Wiley Sons, Ltd, Chichester (2004). 

K. L. Williams, Introduction to X-ray Spectrometry, Allen Unwin, London (1987). 

E. P. Bertin, Introduction to X-ray Spectrometry Analysis, Plenum, New York, NY (1985). 

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