In the outgoing period of the project, specifically carried out at the Museum Conservation Institute - MCI (Smithsonian Institution), the identification of suitable procedure to get the simultaneous extraction of dyes and protein from a single sample was achieved. This step, developed on madder, cochineal, indigo and weld dyed and undyed wool samples, actually brought to two different protocols, which can be used based on the state of conservation of the textile (i.e. for a strong soil contamination, one is more effective than the other): a slightly modified urea protocol and a recently proposed new TCEP/CAA procedure.
In addition, different methods of cleanup and workflow for proteins and dyes were investigated to develop protocols that did not result in a loss of aliquots of the analytes of interest and to maximize the recovery of both components from the extracting solution. These protocols investigated the application of two types of paramagnetic beads, unmodified and carboxylate-coated hydrophilic magnetic beads, and dialysis and stage-tip protocols.
This aimed at ensuring the same high efficiency in terms of analytical sensitivity for both dye and protein, as in their single workflow.
Once the best procedures were identified, during the second year they were applied to same kind of specimens but subjected to a thermal aging protocol. The laboratory dyed and undyed mock-ups were subjected to a progressive thermal ramp, from 200°C to 300°C at different times, thus trying to simulate the conditions of charred archaeological samples to evaluate its effectiveness and determine the survival threshold of proteins and dyes at the various thermal aging steps. These data were compared with FTIR analysis and morphological information by SEM, to also have a correlation between destructive analysis and morphological appearance and nondestructive investigations. A threshold of protein survival was defined, thus allowing us to trace a path for the first time in evaluating the degradation process and the temperatures reached based on protein modifications.
In returning phase at Sapienza University of Rome, Dept of Environmental Biology, the project focused on evaluating the latest aging to reconstruct the trend of protein modifications at different thermal conditions and photo-oxidative stress conditions and then move on to analyzing the archaeological samples from the Vesuvian Area and Greek area. This fundamental step, currently being finalized, aims to validate and enrich the information obtained from the mock-ups by comparing it with unique findings, revealing new information which may be a new key to open a door on the history and events of these materials.
