PYROLYSIS-GAS CHROMATOGRAPHY MASS-SPECTROMETRY OF NATURAL RESINS USED FOR ARTISTIC OBJECTS

Eight resins used as protective layers for paintings, small sculptures, jewelries and artistic furniture, namely, Manila copal, colophony, Venice turpentine, elemi, shellac, dammar, sandarac and mastic were subjected to pyrolysis gas chromatography-mass spectrometry (PY-GC-MS). Significant mass spectral ions were monitored in each pyrogram. A table for identification of such resins based on the most significant ions in the mass spectra of the pyrolysis fragments is proposed. The results of PY-GC-MS analysis of a sample from the earth globe Giovanni Enriques, attributed to the Venetian geographer Vincenzo Coronelli (1650-1718) (Museo della Specola, Department of Astronomy, University of Bologna), are reported as an example of practical application of the method to a real artistic sample.