The need for quantitative analysis of materials arises in many areas of science, industry and other fields of activity. The tasks that may require knowledge of the elemental composition of a particular material are very diverse, including quality control of materials or finished products, the evaluation of precious products or automobile catalysts, the analysis of the age of archaeological finds, or the determination of the authenticity of paintings. Such a number and variety of applications makes compositional analysis methods very popular in the modern world. At the same time, given the need to use these methods on an industrial scale, the key requirements for the method, in addition to accuracy, are ease of use, low cost, and minimal time required to obtain results.
Considering the above, it is not at all surprising that the X-ray fluorescence analysis method has recently become increasingly popular. This method is based on the analysis of the so-called characteristic spectrum scattered by the sample when it is irradiated with X-rays. At its core, the characteristic spectrum is a set of energies of intra-atomic electron transitions between allowed energy levels. The energy of electronic states in an atom depends on the atomic number, and therefore the characteristic spectrum is a unique characteristic of each element of the periodic table. This allows, on the basis of the characteristic spectrum scattered by the sample, to draw conclusions about its elemental composition.
The XRF method is currently one of the most common methods for analyzing the chemical composition of materials, and the demand for XRF analyzers is growing every year. This trend is primarily due to the accuracy and speed of the method, for example, modern XRF analyzers are able to determine the grade of the alloy in just a few seconds, and it will take up to 20 seconds to accurately analyze the composition of the precious metal. Equally important is the ease of use of this method. The XRF method practically does not require sample preparation before measurements, and the spectrometers themselves are easy to use and do not require any specialized knowledge for effective use. At the same time, the method itself is non-destructive in nature, and in no way affects the appearance or performance characteristics of the samples under study. This feature makes the XRF method especially popular for quality control of finished products, or the analysis of precious materials.
Also, the advantages of the method include a variety of spectrometer models that are now available on the market, ranging from portable XRF guns for field use to benchtop analyzers for laboratories. A wide range of spectrometers allows you to choose, depending on the needs of the buyer, either a universal model with a wide range of capabilities for analyzing various materials, or ideal for solving individual specialized tasks.
However, despite all the advantages mentioned above, it should be understood that XRF is not universal and, like any other analysis method, has its limitations. The main limitation of the XRF method is light elements. Due to the strong attenuation of the low-energy characteristic radiation, in combination with the low fluorescence yield of light elements, the XRF method is not applicable for the analysis of the concentrations of elements with atomic number Z < 11. This limits the scope of this method, however, does not impair its performance in cases where light elements are either absent or knowledge of their concentration is not necessary.
Possible areas of application of the method of X-ray fluorescence analysis are quite diverse. The main areas of application are the analysis of metals and alloys (with the exception of the analysis of carbon concentration in steels), the analysis of used automotive catalysts to determine their cost, environmental monitoring of the environment, testing consumer products for compliance with international standards for the content of toxic elements. In general, when solving any task that requires quantitative information about the concentrations in the sample of elements included in the detection area (from sodium to uranium), XRF analyzers will become an indispensable tool. This is especially true for the analysis of concentrations of heavy elements, since XRF is especially sensitive to them, and the accuracy of their determination can reach tens of ppm (parts per million).
In general, the XRF method, despite its limitations, is one of the most promising methods for analyzing the chemical composition of materials. XRF gun is used in many different areas from metallurgy and the ore industry, to archeology and forensics. Due to its accuracy, ease of use and industrial scale application, the demand for this method is growing every year.