Wood artefacts undergo complex alteration and degradation during ageing, and gaining information ... more Wood artefacts undergo complex alteration and degradation during ageing, and gaining information on the chemical composition of wood in archaeological artefacts is fundamental to plan conservation strategies. In this work, an integrated analytical approach based on innovative NMR spectroscopy procedures, gel permeation chromatography and analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC-MS) was applied for the first time on archaeological wood from the Oseberg collection (Norway), in order to evaluate the chemical state of preservation of the wood components, without separating them. We adopted ionic liquids (ILs) as non-derivatising solvents, thus obtaining an efficient dissolution of the wood, allowing us to overcome the difficulty of dissolving wood in its native form in conventional molecular solvents. Highly substituted lignocellulosic esters were therefore obtained under mild conditions by reacting the solubilised wood with either acetyl chloride or benzoyl chloride. A phosphytilation reaction was also performed using 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholan. As a result, the functionalised wood developed an enhanced solubility in molecular solvents, thus enabling information about modifications of lignin, depolymerisation of cellulose and structure of lignin-carbohydrate complexes to be obtained by means of spectroscopic (2D-HSQC-NMR and 31P-NMR) and chromatographic (gel permeation chromatography) techniques. Py-GC-MS was used to investigate the degradation undergone by the lignocellulosic components on the basis of their pyrolysis products, without any pre-treatment of the samples. The application of all these combined techniques enabled a comprehensive characterisation of the whole cell wall of archaeological wood and the evaluation of its state of preservation. High depletion of carbohydrates and high extent of lignin oxidation were highlighted in the alum-treated objects, whereas a good preservation state was found for the untreated wood of the Oseberg ship.
Chemical analysis of ancient residues of pharmaceutical or cosmetic preparations such as balms or... more Chemical analysis of ancient residues of pharmaceutical or cosmetic preparations such as balms or ointments is made problematic by the high complexity of these mixtures, composed of organic and inorganic materials. Consequently, a multi-analytical approach and special caution in the interpretation of the results are necessary. In order to contribute to the improvement of analytical strategies for the characterization of complex residues and to reconstruct ancient medical practices, a replica of a pharmaceutical formulation of the seventeenth century was prepared in the laboratory according to a historically documented recipe. In a round robin exercise, a portion of the preparation was analysed as a blind sample by 11 laboratories using various analytical techniques. These included spectroscopic, chromatographic and mass spectrometric methods. None of the laboratories was able to completely reconstruct the complex formulation, but each of them gave partial positive results. The round robin exercise has demonstrated that the application of a multi-analytical approach can permit a complete and reliable reconstruction of the composition. Finally, on the basis of the results, an analytical protocol for the study of residues of ancient medical and pharmaceutical preparations has been outlined.
International Biodeterioration & Biodegradation, 2014
ABSTRACT Chemical characterization is a valuable tool for assessing the decay of archaeological o... more ABSTRACT Chemical characterization is a valuable tool for assessing the decay of archaeological or historical degraded wood it and is essential in selecting the most appropriate conservation techniques. This paper reports the results on archaeological waterlogged wood remains from the roof of a Roman villa buried in AD 79 by the eruption of Vesuvius. Parts of the wooden roof were excavated in 2009 under several meters of solidified pyroclastic material in the area of the ancient shoreline, in an extremely wet environment. The sampling was undertaken in 2011 and samples were analyzed and characterized within the framework of the Herculaneum Conservation Project. The degradation of the wood was assessed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), an analytical approach that achieves semi-quantitative results on the content of lignin and polysaccharides in degraded wood. The characterization was based on a comparison of the pyrolysis profiles of archaeological wood with sound wood of the same species. To compare samples according to their state of degradation, a multivariate statistical approach based on principal component analysis (PCA) was used. The analyzed samples revealed different levels of lignin oxidation, and different amounts of residual polysaccharide components, even between samples taken from the same fragment of the roof. This means that the wood underwent different degradation pathways, such as degradation by fungi or insects.
21st International Symposium on Analytical and Applied Pyrolysis, Pyro 2016, Poster Session 2: Wednesday 11 May & Thursday 12 May, Nancy, France, 9-12 May 2016., 2016
Wood artefacts undergo complex alteration and degradation during ageing, and gaining information ... more Wood artefacts undergo complex alteration and degradation during ageing, and gaining information on the chemical composition of wood in archaeological artefacts is fundamental to plan conservation strategies. In this work, an integrated analytical approach based on innovative NMR spectroscopy procedures, gel permeation chromatography and analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC-MS) was applied for the first time on archaeological wood from the Oseberg collection (Norway), in order to evaluate the chemical state of preservation of the wood components, without separating them. We adopted ionic liquids (ILs) as non-derivatising solvents, thus obtaining an efficient dissolution of the wood, allowing us to overcome the difficulty of dissolving wood in its native form in conventional molecular solvents. Highly substituted lignocellulosic esters were therefore obtained under mild conditions by reacting the solubilised wood with either acetyl chloride or benzoyl chloride. A phosphytilation reaction was also performed using 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholan. As a result, the functionalised wood developed an enhanced solubility in molecular solvents, thus enabling information about modifications of lignin, depolymerisation of cellulose and structure of lignin-carbohydrate complexes to be obtained by means of spectroscopic (2D-HSQC-NMR and 31P-NMR) and chromatographic (gel permeation chromatography) techniques. Py-GC-MS was used to investigate the degradation undergone by the lignocellulosic components on the basis of their pyrolysis products, without any pre-treatment of the samples. The application of all these combined techniques enabled a comprehensive characterisation of the whole cell wall of archaeological wood and the evaluation of its state of preservation. High depletion of carbohydrates and high extent of lignin oxidation were highlighted in the alum-treated objects, whereas a good preservation state was found for the untreated wood of the Oseberg ship.
Chemical analysis of ancient residues of pharmaceutical or cosmetic preparations such as balms or... more Chemical analysis of ancient residues of pharmaceutical or cosmetic preparations such as balms or ointments is made problematic by the high complexity of these mixtures, composed of organic and inorganic materials. Consequently, a multi-analytical approach and special caution in the interpretation of the results are necessary. In order to contribute to the improvement of analytical strategies for the characterization of complex residues and to reconstruct ancient medical practices, a replica of a pharmaceutical formulation of the seventeenth century was prepared in the laboratory according to a historically documented recipe. In a round robin exercise, a portion of the preparation was analysed as a blind sample by 11 laboratories using various analytical techniques. These included spectroscopic, chromatographic and mass spectrometric methods. None of the laboratories was able to completely reconstruct the complex formulation, but each of them gave partial positive results. The round robin exercise has demonstrated that the application of a multi-analytical approach can permit a complete and reliable reconstruction of the composition. Finally, on the basis of the results, an analytical protocol for the study of residues of ancient medical and pharmaceutical preparations has been outlined.
International Biodeterioration & Biodegradation, 2014
ABSTRACT Chemical characterization is a valuable tool for assessing the decay of archaeological o... more ABSTRACT Chemical characterization is a valuable tool for assessing the decay of archaeological or historical degraded wood it and is essential in selecting the most appropriate conservation techniques. This paper reports the results on archaeological waterlogged wood remains from the roof of a Roman villa buried in AD 79 by the eruption of Vesuvius. Parts of the wooden roof were excavated in 2009 under several meters of solidified pyroclastic material in the area of the ancient shoreline, in an extremely wet environment. The sampling was undertaken in 2011 and samples were analyzed and characterized within the framework of the Herculaneum Conservation Project. The degradation of the wood was assessed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), an analytical approach that achieves semi-quantitative results on the content of lignin and polysaccharides in degraded wood. The characterization was based on a comparison of the pyrolysis profiles of archaeological wood with sound wood of the same species. To compare samples according to their state of degradation, a multivariate statistical approach based on principal component analysis (PCA) was used. The analyzed samples revealed different levels of lignin oxidation, and different amounts of residual polysaccharide components, even between samples taken from the same fragment of the roof. This means that the wood underwent different degradation pathways, such as degradation by fungi or insects.
21st International Symposium on Analytical and Applied Pyrolysis, Pyro 2016, Poster Session 2: Wednesday 11 May & Thursday 12 May, Nancy, France, 9-12 May 2016., 2016
Uploads
Papers by F. Modugno
POSTER by F. Modugno