Synergism between SEM/EDX microanalysis and multivariate analysis for a suitable classification of Roman and Byzantine papyri

Elder manuscripts constitute a remarkable source of potential information about antiquity societies, where the inks more than the supports represent the most valuable informative evidence. However, the achievement of this information requires the use of powerful analytical tools. In this work, we assayed Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray (EDX) spectrometry as an adequate analytical tool for the evaluation of the elemental composition of the inks and supports of several Roman and Byzantine papyri in the Palau-Ribes collection, Barcelona (Spain). The elemental composition of the papyri studied served successfully to establish a proper statistical classification and/or differentiation between papyri, according to their historical period. Various chemometric approaches were assayed for that purpose, but the principal component analysis and particularly the linear discriminant analysis allowed us to group the papyri studied, from which we could retrieve information about their similarities and differences. Using the linear discriminant analysis and based on the five most statistically significant elements, we obtained two equations for the papyri classification.