INTRODUCTION

X-ray fluorescence (XRF) spectrometry is an instrumental method based on the measurement of characteristic X-ray photons caused by the excitation of atomic inner-shell electrons by a primary X-ray source. The XRF method can be used for both qualitative and quantitative analysis of liquids, powders, and solid materials. The X-rays produced by an X-ray tube include characteristic lines that correspond to the anode material and a continuum known as Bremsstrahlung radiation. Both types of X-rays can be used to excite atoms and thus induce X-rays. XRF instrumentation can be divided into one of two categories: Wavelength Dispersive X-ray Fluorescence (WDXRF) and Energy Dispersive X-ray Fluorescence (EDXRF). The main factor distinguishing these technologies is the method used to separate the spectrum emitted by the atoms in the sample. The energy of the X-ray photon is characteristic for a given electron transition in an atom and is qualitative in nature. The intensity of the emitted radiation is indicative of the number of atoms in the sample and constitutes the quantitative nature of the method.