Ricerc@Sapienza

tThis paper presents an investigation of yellow pigments based on lead, tin and antimony through X-rayfluorescence spectroscopy with the aim of comparing portable and laboratory instruments and discussingthe potential application on artworks. Artificial yellow pigments, based on Pb-Sb-Sn, and produced inour laboratory, were chosen in order to have a well-known and already characterized sample set. Thedifferentiation in artworks of these pigments is still a challenge if non-invasive portable X-ray spectro-meters are used, as commonly occurs in practice. The analysis was performed by using the Bruker M4Tornado laboratory equipment and the Assing Surface Monitor II portable apparatus. Scanning electronmicroscopy with energy dispersive spectroscopy was also applied for a semi-quantitative analysis ofthe chosen pigments. In order to perform a significant statistical comparison of acquired and processeddata, 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 theprincipal component analysis and multivariate analytical tools, was applied in order to verify the spec-tral differences, and related informative content, between the different produced yellow pigments. Themultivariate approach revealed instrumental differences between the two systems and allowed the com-parison of the common characteristics of the analyzed pigments set. The potential of this new approachis also linked to the possibility of differentiating artificial yellow pigments, both in terms of compositionand, above all, in terms of recipes for their production.