Identification of organic binding media in ancient architectural decoration by THM–Py–GC/MS

Abstract

Animal glue, pine resin, starch, and tung oil were commonly used as binding media in ancient architectural decoration in China. Gum benzoin was also recorded in ancient Chinese literature but has not been detected in Chinese architectural decoration yet. To obtain comprehensive information on ancient binding media, this study investigated two types of gum benzoin using pyrolysis–gas chromatography/mass spectrometry with thermal-assisted hydrolysis and methylation (THM–Py–GC/MS). Subsequently, organic binding media used in the architectural decoration of Shuxiang Temple, which is a Royal Manchu temple in the Qing dynasty, were analyzed. Heat-boiled tung oil was identified as the major binding medium in architectural decoration. In addition, animal glue, blood, starch, pine resin, and gum benzoin from Styrax benzoin Dryand and Qi (urushiol-based lacquer) were also determined. For the first time, gum benzoin was detected as a binding medium in architectural decoration in China. The identification of various organic binding media used in the architectural decoration can provide scientific support to the ongoing conservation project related to Shuxiang Temple.