USE OF ANALYTICAL PYROLYSIS TO CHARACTERIZE EGYPTIAN PAINTING LAYERS

An Egyptian wooden sarcophagus and a cartonnage (664-525 B.C.) were su bjected to pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS) a nd Fourier-transform infrared spectroscopy (FT-IR) in order to charact erize pigments and organic binding media. The aim of these investigati ons is to acquire a better knowledge of the painting technique used in ancient Egypt. Results showed that PY-GC-MS offered a rapid tool to d iscriminate between wax-based- and animal protein-based binders and to recognize the use of mixtures of the two products. FT-IR corroborated the pyrolysis findings, but sometimes provided less unequivocal resul ts than PY-GC-MS. As an additional benefit, PY-GC-MS allowed the ident ification of a yellow pigment as the arsenic sulphide orpiment by mean s of the volatile As-4 among the pyrolysis fragments.