Molecular pattern recognition of fresh and aged shellac

Two GC-MS procedures for the characterization of shellac, an animal resin widely used in the field of art, were developed. One procedure was based on pyrolysis assisted by the hexamethyldisilazane reaction on-line with GC-MS and the other on the saponification of the sample assisted by microwave followed by GC-MS analysis. The former is a rapid and valuable method for resin identification and the latter gives a more in depth understanding of its composition. Butolic, aleuritic and its derivative acids together with typical sesquiterpenoid compounds were the main molecules identified and used as markers for the molecular pattern recognition of the resin in fresh and old samples (19(th) century shellac from the Solvemini Collection and gilding samples from the 15(th) century frescoes of the Duomo of Monza).