XRF and state-of-the-art related techniques to the study of teeth, tartar and oral tissues

H. J. SÁNCHEZ; M.S. GRENÓN

X-Ray Fluorescence in Biological Sciences: Principles, Instrumentation and Applications

John Wiley & Sons

Lugar: Chichester; Año: 2022; p. 491 - 507

In 1913, Moseley presented his empirical law that related the atomic number with characteristics x-ray emitted by the elements [1]. Briefly, Moselse´s Law states that the square root of the characteristics x-ray energies is proportional to the atomic number. This equation represents the birth of qualitative analysis by x-ray characteristic emissions. Subsequently, many authors established several rules and laws in order to settle a relationship between the number of photons on a certain element, emitted by an excited sample, and the concentration of that element. It was not until the 1950´s that Sherman [2] and later in 1966 Shiraiwa and Fujino [3] presented the formal description of the fluorescent intensity emitted by an excited sample in terms of the concentrations of the elements present in the sample and the fundamental parameters associated. Since then, x-ray fluorescence (XRF) analysis has become a well-established technique providing precise and accurate quantitative determinations of the concentrations of practically every type of sample in a variety of conditions. In particular, samples of biological sources, even in-vivo ones. The technological advances during the second half of the last century gave place to innovation with respect to the typical excitation/emission methodology. Thus, the access to more intense sources of x-ray photons like rotating x-ray tubes and the advent of synchrotron light facilities allowed to reduce detection limits and to get extreme beam conformations and collimations. In addition, more powerful and versatile detection devices allowed to set up singular and particular geometries. All these changes leaded to new methodologies and innovative techniques such as Micro-XRF Analysis [4], Spatially Resolved XRF Analysis [5], Total Reflection XRF Analysis [6], Grazing Incidence [7], and Grazing Exit Analysis [8], and many other techniques associated to x-ray fluorescence such as the novel EDIXS technique [9].