Multifractal analysis of elemental distributions in SEM/EDX images of palladium conditioned ET-AAS platforms

Abstract

A tool of non-linear physics, the multifractal analysis of density distributions, is applied to the analysis of elemental dot maps imaged by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX). This example concerns distribution patterns of palladium modifier deposits on the graphite platform of an electrothermal atomic absorption spectrometer (ET-AAS). The geometries of palladium distributions were quantitatively determined by multifractal analysis for two types of modifiers: (i) 0.1% (w/v) tetraamminepalladium (II) chloride and (ii) 0.1% (w/v) tetraamminepalladium (II) chloride with 1% (w/v) ammonium oxalate. The multifractal spectra of the generalized fractal dimensions (D _b (q)) do not differ forq = 0 (D _b (0) ≈ 1.80±0.08), which reflects the surface topography of the graphite platform. For higher moments ofq significant differences occur (e.g.,D _b (10) ≈ 1.35±0.13 without ammonium oxalate andD _b (10) ≈ 1.55±0.10 in the presence of ammonium oxalate). These multifractal characteristics, which are due to different probabilities of deposition processes, were observed over a spatial range around 0.01–1 mm. The quantitative assessment of the geometrical distributions substantiate that ammonium oxalate promotes processes which lead to a more homogeneous distribution of palladium, thus enhancing the stabilizing effect.