Historical proteinaceous-based pictorial binders’ analysis: a novel proteomic minimally invasive approach

Operating micro-invasive sampling when dealing with the chemical investigation of precious historical works of art is, without doubts, mandatory. Recently, scientific research in the field of Cultural Heritage has been often devoted to the development of innovative strategies for quasi non-invasive sampling on works of art to extract, for example, proteins and/or lipids composing the pictorial binders gaining extensive awareness about the materials employed by the artist. In this work, we propose a novel minimally invasive method for the sampling and characterization of protein-based painting binders. We apply a hydrophilic gel, previously functionalized with trypsin and chymotrypsin, on the artwork surface to perform an in-situ digestion of proteinaceous binders. Peptides are identified by means of a proteomic bottom-up approach combined with a high resolution/accuracy mass spectrometry technique. A wooden polychrome statue belonging to the XV century was chosen as a sample to assess the proposed protocol on a historical painting layer, as illustrated herein.