Degradation by-products of ancient paper leaves from wash waters

Water cleaning of paper leaves is a preliminary step in many customary deacidification treatments of ancient books in conservation workshops. Usually, the washing solutions are considered "waste waters" and they are thrown away. In this work, an analytical protocol for the analysis of wash waters for the assessment of the conservation state of ancient books is proposed. Wash waters of leaves under different conservation conditions of a 16th-century-printed book were investigated using UV-Vis, IR, Raman, NMR, EPR, XRF, ESI-MS, ICP-MS, CE-PDA and elemental microanalysis. Analysis of the wash water extracts allowed one to identify a large number of degradation by-products, ranging from low-molecular mass organic acids to cellulose oligomers. Reasons for the very different conservation conditions of the leaves emerged, indicating that wash water analysis provides a deep insight into the conservation state and composition of leaves as well as degradation reactions occurred on them.