Characterization of the residues in Han Dynasty bronze lamps by pyrolysis–gas chromatography–mass spectrometry

The fuel residues in two bronze lamps excavated from Haihunhou Tomb in the Han Dynasty, in Jiangxi Province, China, were studied in this paper. The techniques of Fourier transform infrared (FT-IR) spectroscopy and pyrolysis–gas chromatography–mass spectrometry with thermal-assisted hydrolysis and methylation (THM-Py–GC/MS) were used to characterize the materials. Long-chain fatty acids, fatty alcohols and hydrocarbons were detected as the main components. By comparing the reference materials of beeswax and Chinese wax, the residues in the lamps were identified as beeswax. Furthermore, according to the morphology of the remains of the lamp fuel, the fuel remains were probably melted and then solidified, which suggests the lamps were used. Wax was found to have been used as an illuminating fuel as early as the Han Dynasty, enriching scholarly knowledge about the lighting materials used in ancient China.