Characterisation of oriental lacquers from Rhus Succedanea and Melanorrhoea Usitata using in situ pyrolysis/silylation-gas chromatography-mass spectrometry

Two oriental lacquers from Rhus Succedanea and Melanorrhoea Usitata were characterised by Py-GC-MS with in situ silylation using HMDS. Pyrolytic markers, which were helpful in differentiating between the lacquers, were identified in their silylated forms, and the mass spectra are presented and discussed. Aliphatic and aromatic hydrocarbons were formed as well as TMS derivatives of alkylcatechols and alkylphenols, and relative characteristic pyrolytic profiles were compared for the two lacquers. The method, here applied for the first time to the characterisation of the Vietnamese and Burmese lacquers, proved successful not only in distinguishing between the two lacquers, but also in highlighting the polymerisation processes undergone by the saps in the formation of the lacquer layers.The results obtained demonstrated that in situ Py/silylation-GC-MS with using HMDS is a suitable tool for the analysis of all oriental lacquers with possible application to diagnose their presence in samples of unknown composition.