High-resolution solid-state CPMAS NMR study of archaeological woods.

High-resolution nuclear magnetic resonance of carbon-13 was employed to characterize archaeological wood samples from the 11th century excavation site in the lake Paladru at Charavines, France. Structural and chemical modifications were assessed by comparing the structural features of archaeological wood of beech with modern wood. The main results concern the strong decrease of a sugar moiety with a complete disappearance of hemicelluloses. During aging in a water environment, the beta-O-4 interunit linkages of lignins have not been degraded. The analysis of the NMR spectra reveals that the residues occurring during depletion of sugars were not recombined inside the lignocellulosic matrix. Finally, in this article we illustrate the possibility of analyzing small amounts (4-6 mg) of starting material within reasonable experimental time using modern equipment.