Caroline TOKARSKI, researcher from Institute of Chemistry & Biology of Membranes & Nano-objects – CNRS, Proteome Platform, University of Bordeaux will give a lecture on “How proteomics and advanced mass spectrometry are reshaping what we can learn about paintings, objects and cultural heritage” the 15th  November 2022 at the Institute for Analytical Sciences (11:00 am – seminar room).

Abstract: For 20 years now, bio-mass spectrometry has been changing the analytical landscape of art, archaeology and cultural heritage. Alongside the technical improvements, the continuous emergence of new applications allows improved structural elucidation of ancient components and interacting biomolecules – as varied in structure as in their complexities, that are ancient lipids, polysaccharides and proteins. From a few micrograms of precious sample from an object, it is now possible to obtain protein identity sequences and to discriminate biological species on a single amino acid basis. In addition to this improved investigative process, enhancing knowledge of artworks / heritage objects and preservation approaches, we are now confronting, in heritage mass spectrometry, an even more complex issue of chemical decoding of biomolecular networks, their fine characterization, the study of cross-linking mechanisms, as well as the understanding of their modifications and interactions.

This presentation will illustrate how protein/lipid chemical signatures inform about ancient material manufacturing processes and conservation practices, and the impact of these procedures on macromolecules’ structures. It will also illustrate how molecular information informs on societal, cultural and economic aspects of the past communities.

In this context, the presentation will describe our latest developments in bottom up, top-down and hydrogen deuterium exchange mass spectrometry to address complex questions of molecular interaction in networks in unaged and aged forms. Protein conformational changes and pigment interactions occurring during paint formulation, drying and ageing will be discussed. Analytical evidence of protein crosslinking in historic artworks and objects will be presented and discussed. Other examples will also demonstrate the whole mass spectrometry capabilities in elucidating restoration procedures, based on specific chemical signature monitoring. The presentation will show how our most recent miniaturized analytical procedures for trace level analysis have provided insight into artists’ working methods or objects’ provenance. Finally, the presentation will show how high resolution (lateral and mass) MALDI imaging can decode the biomolecular organization of paint layers by identifying and mapping both high and low molecular weight ions for molecular structure characterization. We will demonstrate the suitability of the technique to locate and monitor intact materials and by-products within samples, at the surface, within the layers and at layer interfaces of artworks.

These examples will be illustrated by several outstanding cases of study from the Metropolitan Museum of Art collection in the context of the ARCHE international laboratory – ARt and Cultural HEritage: Natural Organic Polymers by Mass Spectrometry. Painted textiles and storage jars from ancient Egypt, African sculptures and Power Figures, Egyptian ivories, Chimú feather work, Coptic manuscripts, and paintings spanning the 15th to the 20th centuries will be a part of this presentation.