More insight into characterization of the waterlogged wooden part of Acqualadroni Roman Rostrum by solid-state NMR

Abstract

Solid-state NMR spectroscopy was applied to characterize the wooden part of a roman Rostrum recovered in the Tyrrhenian Sea in the Acqualadroni area (Messina, Italy). The Acqualadroni Rostrum has been, in the recent past, investigated to establish its provenance and conservation. In this paper, solid-state NMR was used to obtain information on the conservation state of the wood as a preliminary step for the conservation process.A wooden sample of this artifact, collected by coring, was divided in four parts in order to correlate the conservation state to the depth. Results were compared with those obtained for a modern wood of the same species.A structural study was performed by acquiring 13C cross-polarization magic angle spinning spectra to evaluate the cellulose crystallinity degree and the lignin condensation degree. In addition, the holocellulose–lignin ratio and the cellulose–lignin residual interactions were determined through variable contact time experiments and relaxation times determination respectively.Being the solid-state NMR a non-destructive technique, all measurements were performed with no modification of the samples such as solvent extraction or other chemical treatment, making the samples available for further analytical investigation.