PyGC/MS, NMR, TEM, FT-IRを用いたYOKOGUSHIアプリケーションが「日本化学会 第98年会」で発表されました


続報は「日本化学会 第99年会」(2019, March16-19@甲南大学)で発表されます。

"Detection of the gum from a Japanese lacquer film"
N.Niimura, H.Nishioka, H.Terashima, O.Kamo, Y.Shimoikeda, H.Sasakawa


Japanese lacquer has been used as the coating material for a long time, because it dries into a tough film. There are lots of historical artistic handicrafts, art objects and architectures coated with Japanese lacquer. Some of them are designated national treasures and others are registered on the World Heritage List. In restoration work, it is important to characterize the lacquer. The lacquer sap just tapped from lacquer trees is a milky-white water-in-oil emulsion. The main component of the oil is urushiol, and plant gum is solved in the water. Detection of the gum is important to identify the lacquer film.
We have reported that pyrolysis gas chromatography/mass spectrometry (PyGC/MS) is effective to characterize Japanese lacquer films.1-4 However, the gum has not been detected from the lacquer films using this method. In this study, we successfully detected it using Py chemical ionization (CI) MS, solid state nuclear magnetic resonance (NMR) spectroscopy and Fourier transform-infrared spectroscopy (FT-IR). Furthermore, a large number of cavities with a diameter of several tens of nm to several µm were observed in the cross-section transmission electron microscopy (TEM) image. It was found that the gum is in the cavities. As described above, the lacquer sap is water-in-oil emulsion. During the drying process of the emulsion to form the lacquer film, water evaporates and the cavities are left, in which the gum is deposited.


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