Multi-Technique Characterization of Pictorial Organic Binders on XV Century Polychrome Sculptures by Combining Micro- and Non-Invasive Sampling Approaches

A stony sculptural composition of the Nativity Scene is preserved in Altamura’s Cathedral (Apulia, Italy). This commonly called Apulian “presepe”, attributed to an unknown stonemason, composed polychrome carbonate white stone sculptures. While earlier stratigraphic tests have unveiled a complex superimposition painting layers—meaning that several editions sculptures succeeded from 16th 20th century—a chemical investigation intended identify organic binding media used layers was undertaken. Drawing on current literature, two strategies were exploited: non-invasive situ digestion analysis and approach based micro-removal film followed by Bligh Dyer extraction protocol. Both peptide lipid mixtures analyzed matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) reversed-phase liquid chromatography coupled mass electrospray ionization (RPLC-ESI-MS). Attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) examinations also performed micro-samples films before lipids proteins extraction. human keratins found be common contaminants artwork’s surfaces, traces animal collagen, siccative oils, egg evidenced different sampling zones sculptures, thus suggesting use non-homogeneous techniques colored layers.