Imaging and quantification of trace metals in thin biological specimens using microprobe techniques: Synchrotron induced X-ray fluorescence microprobe and nuclear microprobe

Abstract

The combination of Synchrotron X-Ray Fluorescence microprobe (SXRF) with other micro-analytical techniques based on accelerated particle beams, such as Rutherford Backscattering Spectrometry (RBS), and Particle Induced X-ray Emission (PIXE) enable to quantify SXRF results of thin biological specimens. The same specimens were analysed by both techniques. The average thickness calculated by RBS of discrete tissue regions in equivalent sample sections was used to normalise SXRF data. Analysing the same sample region with PIXE technique, simultaneously to RBS, can validate the methodology once it will enable to compare concentrations obtained for elements that are detected by both SXRF and PIXE. Major departures were found for the quantification of Ca and Ti. For Cr and Fe a good agreement was found between both micro-analytical techniques. Differences below 20% were obtained for the majority of the elements and samples analysed. The procedure can be applied to produce quantitative elemental maps and it will be advantageous to quantify toxic elements present at low concentrations in tissues, such as Cr, Ni and Pb, which can only be efficiently assessed by SXRF.