Analytical characterization of binding medium used in ancient Chinese artworks by pyrolysis–gas chromatography/mass spectrometry

In the present work, we attempted to characterize the natural organic binding medium mostly used in ancient Chinese artworks by using the pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) technique. Chinese lacquer, tung oil, deer glue, colophony and peach gum were broadly used as binding media in Chinese paintings or painted pottery, and have been selected as the study materials in this paper. Artificially aged samples have been analyzed by Py–GC/MS in order to establish a useful reference as convenient and rapid analyses of real samples. The method is based on the on-line derivatization in the presence of excess tetramethylammonium hydroxide (TMAH) (25% aqueous solution) as methylating agent. Analyses results revealed that this simultaneous pyrolysis with methylation derivation technique (SPM) is very useful to the characterization of Chinese lacquer, tung oil and colophony but no obvious improvement to deer glue and peach gum. The fingerprint ions of each studied binding medium were established.