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.