Atomic spectrometry update: review of advances in X-ray fluorescence spectrometry and its special applications

Three-dimensional chemical imaging by XRF spectrometry techniques continues to advance in both experimental methods and quantitative data evaluation and reconstruction strategies. These techniques are gaining interest across various research fields, ranging from material science and environmental and Earth sciences to life science and biomedical imaging. Two primary techniques associated with 3D XRF spectrometry are reviewed in this update: XRF spectrometry CT and confocal XRF spectrometry. There has been an increase in the building of in-house specialised 2D XRF spectrometry instruments. Attention to various components, e.g. coating of optics, has improved performance. There was an increase during the review period in the use of SR-XRF spectrometry in conjunction with complementary X-ray spectroscopic and imaging techniques for integrating spatially resolved elemental data with information on speciation and structural and morphological images. Applications of μXRF spectrometry continued to expand in fields such as biomedical, environmental and materials sciences and cultural heritage research. These applications were primarily carried out at specialised hard-X-ray micro- and nano-probe facilities by combining SR-XRF spectrometry with micro- and nano-XAS, XRD analysis, ptychography and various forms of tomographic techniques. The TXRF spectrometry technique continues to be successfully implemented in medical research because of its outstanding performance as a microanalytical method. Changes in the elemental profiles of small organs from, e.g. rats, can be detected. The introduction of a versatile pipetting instrument made possible significant advances in the strategic identification of errors in sample morphology. MacroXRF spectrometry continues to play a significant role in cultural heritage applications. Instrumentation is constantly expanding with new functionalities such as simultaneous measurement with reflectance image spectroscopy and luminescence imaging spectroscopy. The investigation of papyrus fragments was enhanced by upgrading a novel mobile macroXRF spectrometer scanner with new high-performing mechatronics and a high-throughput detection system.