X-ray fluorescence investigation on yellow pigments based on lead, tin and antimony through the comparison between laboratory and portable instruments

Abstract

© 2017 Elsevier Masson SAS This paper presents an investigation of yellow pigments based on lead, tin and antimony through X-ray fluorescence spectroscopy with the aim of comparing portable and laboratory instruments and discussing the potential application on artworks. Artificial yellow pigments, based on Pb-Sb-Sn, and produced in our laboratory, were chosen in order to have a well-known and already characterized sample set. The differentiation in artworks of these pigments is still a challenge if non-invasive portable X-ray spectrometers are used, as commonly occurs in practice. The analysis was performed by using the Bruker M4 Tornado laboratory equipment and the Assing Surface Monitor II portable apparatus. Scanning electron microscopy with energy dispersive spectroscopy was also applied for a semi-quantitative analysis of the chosen pigments. In order to perform a significant statistical comparison of acquired and processed data, all the analyses have been carried out by using the same sample, the same acquisition set-up and, at the same time, operative conditions for both instruments. A chemometric approach, based on the principal component analysis and multivariate analytical tools, was applied in order to verify the spectral differences, and related informative content, between the different produced yellow pigments. The multivariate approach revealed instrumental differences between the two systems and allowed the comparison of the common characteristics of the analyzed pigments set. The potential of this new approach is also linked to the possibility of differentiating artificial yellow pigments, both in terms of composition and, above all, in terms of recipes for their production.