Pyrolysis Gas Chromatographyª²Mass Spectrometry Applied to Identification of Oils in
Ancient Paintings
He Ling1,Nie Maiqian2,Giuseppe Chiavari3
£¨1.School of Sciences£¬Xi'an¡¡Jiaotong¡¡University£¬Xi'an 710049£¬China; 2. School
of Environmental and Municipal Engineering, Xi'an University of Architecture and
Technology, Xi'an 710055,China; 3. Department of Chemistry, University of Bologna, Bologna
40126, Italy)
Abstract£ºThe siccative oils were identified via pyrolysis gas chromatographyª²mass
spectrometry for linseed oil, walnut oil, poppy oil and tung oil used as binding media in
ancient paintings. The finger marker as a convenient and rapid reference for the
characterization of real samples was established according to the analysis of aged
standard oil layers and evaluated while the simultaneous pyrolysis with methylation
derivation technique was adopted. The results indicate that it is possible to identify and
distinguish these siccative oils because the unsaturated acid had changed into azelaic due
to oxidation and polymerization during the drying process to make the chromatogram of
siccative oils have a typical peak of C9 compound (methylated azelaic acid) and provide a
finger marker of m£¯z 217, and the concentration ratio of palmitic acid to stearic
acid remains constant with time to facilitate the differentiation of oils. The proposed
method is expected to effectively identify individual siccative oils as binding media in
ancient paintings.
Keywords£ºsiccative oil; pyrolysis gas chromatographyª²mass spectrometry; binding media;
palmiti cacid; stearic acid