ABSTRACT
X-rays were discovered in 1895 by Wilhelm Conrad Röntgen who received the rst Nobel Prize in Physics, awarded in 1901, for his discovery. X-ray absorption, emission, and uorescence spectra are used in the qualitative and quantitative determination of elements in solid and liquid samples. XRA is used in the nondestructive evaluation of aws in objects, including voids or internal cracks in metals, cavities in teeth, and broken bones in humans, a technique called radiography or X-ray uoroscopy. This same technique is used to perform security screening of baggage at airports. A computerized version of radiography, computed tomography (CT) scanning or computed axial tomography (CAT), provides a powerful, high-resolution medical diagnostic tool by giving a 3D cross-sectional image of body tissues. Diffraction of X-rays by crystalline materials, a technique called X-ray crystallography, provides crystal structure identication, orientation of atomic planes in materials, and other physical information about samples. X-ray astronomy uses cosmic X-rays to study the universe, and X-ray spectrometers have been sent to the moon and Mars to study the surface rocks in situ. This chapter will focus primarily on X-ray uorescence (XRF) spectrometry and X-ray diffractometry (XRD), the techniques of most use to analytical chemists.
