Atomic spectrometry update: review of advances in X-ray fluorescence spectrometry

Abstract

This review of 89 references covers advances in X-ray fluorescence spectrometry and its special applications, published from April 2024 to March 2025 inclusive. It provides critical insights into developments in instrumentation, methodologies and data handling, representing significant progress in XRF spectrometry. Applications of cultural heritage are also covered. Highlights of this review period include notable research findings. A method was developed to overcome self-absorption effects in confocal XRF spectrometry, enabling quantitative and distortion-free 3D elemental analysis by combining sample density information from μCT with mass attenuation coefficients from absorption measurements. Additionally, compositional data from fundamental parameter quantification of reference-free XRF spectrometry for ‘dark matrix’ elements like C, N and O in the soft X-ray region were incorporated. Using SR-XRF spectrometry, quantitative nano-characterisation of ion beam-implanted samples, particularly focusing on Ga dopants in silicon, was achieved. This method detected a minimum of 3000 Ga atoms per pixel with a 1 s integration (171 nm² spot) and 650 Ga atoms with a 25 s integration, corresponding to LODs of 18 impurities per nm² and 3.8 impurities per nm², respectively. The determination of elemental profiles in size-segregated airborne particulates with high time-dependent resolution (in <1 h) made significant progress with the development of an impactor specifically designed for TXRF spectrometry. A laboratory scanning-free GEXRF spectrometry setup featuring off-the-shelf equipment such as a Cr X-ray tube and a CMOS detector, showed remarkable results, providing measurements close to those obtained from SR facilities, such as the line height of Ti-oxide nanostructures (58 nm) and HfO₂ thicknesses (2.3 nm). We can expect a considerable increase of research in this area in the future. This year, reviews were published highlighting the advancements and applications of hand-held XRF spectrometry techniques over time, specifically for measuring bone lead and for determining the elemental composition of food samples. A comprehensive review provided an overview of synchrotron applications for cultural heritage over the past decade.