Mass spectrometric analyses and imaging of materials found in paint cross-sections from replica works of art.

摘要

The use of laser desorption/ionization (LDI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry was investigated for the analysis of replica paint cross-sections, mimicking the composition of 15th and 17th century works of art.;The composition of paintings from that time period can include materials such as inorganic complexes, small molecules, and peptides/proteins. Understanding the localization and characteristics of the ions desorbed from the replica paint crosssections is essential to mapping out the stratigraphy of the sample. A section from a real work of art can be quite complex and can often show how layers migrate and interact with each other over time. Developing techniques to gain a deeper understanding of layer interactions and delocalization can aid in the conservation and restoration efforts for renowned works of art.;LDI was used for the detection of lipids that originate from the egg-containing layers of paint cross-sections created to replicate works from the Old Masters; analyses of standards mimicking old world paints were also studied for comparison. The results indicate that localization of the egg compounds within the replica paint cross-section is possible by LDI mass spectrometric imaging. Metal complexes originating from the ionization of pigments were also localized within the cross-sections through the use of LDI. Next, MADLI MS, with matrices (including 2,5-dihydroxybenzoic acid (DHB)) was used to develop methods to localize peptides found in both egg and glue binders within replica paint cross-sections. An on-section digestion protocol was modified and tested for the analysis of peptides from glues that fall within the mass range of the instrumentation used. Future work will further explore proteinaceous materials in art work.;This dissertation describes the mass spectrometric methodologies which allow for both the characterization and localization of materials that can be found in layers of replica paint cross-sections. Following a brief introduction to cultural heritage and MSI, the developed methodologies are utilized for two applications: 1) LDI MSI and MSn analyses of lipids found in replica paint cross-sections and 2) on-section enzymatic digestion for the analysis of peptides in fine art samples. It also explores the future directions for this research project which include the exploration of other mass spectrometry techniques for this novel application, such as laser ablation electrospray ionization (LAESI) MS.