Multimodal mass spectrometry imaging to study aged cognac barrels

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Mass spectrometry imaging (MSI) is based on recording mass spectra at regular intervals on a surface, which can then be used to reconstruct ion density maps that are called mass spectrometry images. Several methods exist to produce ions from the surface, and among them two are particularly popular, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and matrix assisted laser desorption-ionization (MALDI). The first makes it possible to record images of organic and inorganic ions at a spatial resolution of less than one micron, and also allows depth profile analyzes. The second allows access to larger biomolecules and, if coupled with Fourier transform mass spectrometers, provides excellent mass resolution (R > 100,000) and mass accuracy (1-2 ppm) at a spatial resolution of a few microns. These two methods are highly complementary and will be developed further for a new application area, namely cultural heritage studies. This will be exemplified on cognac barrels made from different wood and originating from different cooperages with an age of up to 150 years. Ion images will be analyzed by new algorithms for the analysis of transport and diffusion processes. The identification of metabolites will be based on LC-MSMS data of extracts which is analyzed by advanced metabolite network algorithms (‘molecular networks’). In the first part temporal changes of wood (staves) by contact to the distillate on the one side and the atmosphere on the other side will be investigated. The composition of the staves is changed by the evaporation of alcohol - the so-called Angel’s share. The analysis of cross sections of staves will lead to a better understanding of immaterial cultural heritage of traditional methods and the influence of wood barrel aging on product quality. The second part of this project is focused on the interaction of wood barrels with the fungus Baudoinia compniacensis. This fungus causes the blackening of outside and inside cellar walls, but never grows directly on the wood barrels. Therefore, we will investigate which components of the oak wood are responsible for the reduction of fungus growth. A better understanding of the molecular processes of wood fungus interaction can form the basis for environmentally friendly strategies to reduce this (an other) fungus species.