Analysis of Organic Residue in a Wooden Vessel Excavated from a Tomb of Japanese Samurai Buried in the Seventeenth Century.

TOMBS; SEVENTEENTH century; SAMURAI; ABIETIC acid; GAS chromatography/Mass spectrometry (GC-MS); TOKUGAWA Period, Japan, 1600-1868; JAPANESE people; ARCHAEOLOGICAL excavations

An archaeological sample of organic residue in a noble wooden vessel excavated from the tomb of Japanese Samurai named Tsunamune Date who was buried in 1711 was analyzed using Fourier-transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry. The lipid extracts of plant nuts and vegetable oils were also measured as references to investigate source materials of the organic residue. The FT-IR spectrum suggests the occurrence of fatty acids in the sample, and the profile was similar to the result of IR analysis at the excavation event in 1983. This implies that the major components in the organic residue have not deteriorated, even though it has been stored at room temperature nearly 40 years. The fatty acids and their degradation products, dicarboxylic acids, were detected in the organic residue, implying that plant oil may be included in the sample. In addition, three diterpenes, pimaric acid, dehydroabietic acid, and abietic acid, and another four compounds derived from rosin were clearly identified. This result suggests that the sample analyzed here may be a mixture of lipid extracts of wax and lacquer tree nuts and rosin. Based on the ancient documents in the Edo periods (seventeenth-nineteenth centuries) in Japan, it was surmised that Tsunamune Date used the organic residues as either medical ointment or hairstyling foam in his life. [ABSTRACT FROM AUTHOR]