Characterization of Tang Dynasty lamp oil remains by using pyrolysis gas chromatography and mass spectrometry

• Archaeological lamp oil remains was analyzed.
• Direct Py-GC/MS, THM-Py-GC/MS, and Py-GC/MS with double-shot methods were carried out for the analyses.
• perilla oil, cedar oil and compounds from urushi were identified in the lamp oil remains.

This paper presents the results of the analysis investigation of the lamp oil remains from a Tang Dynasty tomb (901 AD) in Lin An County, Zhejiang Province of China. The techniques applied include direct pyrolysis gas chromatography and mass spectrometry (Py-GC/MS), Py-GC/MS with in-situ hydrolysis and methylation, as well as Py-GC/MS with double-shot method. Through the analysis, plant oil—most likely perilla oil was identified in the sample. The detection of the aromatic compounds (such as calamene, calamenene, cycloisolongifolene, 8,9-dehydro-neoisolongifolene, cadalene, cedrene, ylangene, cuparene and cedrol) indicates the presence of cedar oil and other essential oils in the lamp remains. Unexpectedly, the marker compounds of urushi including methyl 7-(2,3-dimethoxyphenyl) heptanoate, methyl 9-(2,3-dimethoxyphenyl) nonanoate and 1,2-dimethoxy-3-pentadecylbenzene were also detected in the sample.