GC-MS analyses of ring degraded triterpenoids in event deposits

Abstract

Ring degraded triterpenoids, in which cyclic structure is opened and/or cleaved, were commonly identified in sediments and peats. These degraded triterpenoids such as des-A, des-E, and C ring-cleaved triterpenoids are considered to be formed by microbial and/or photochemical processes during transport and deposition. In the present study, we analyzed the ring degraded triterpenoids using GC-MS in the event deposits such as turbiditic sediments of the Miocene Kawabata Formation from Yubari, central Hokkaido, and a tsunami deposit in the Holocene peat core from Kiritappu area, eastern Hokkaido. We identified various des-A and des-E triterpenoids and C-ring cleaved triterpenoids including aliphatic and aromatic hydrocarbons as well as ketones. In addition, mass spectra of unidentified des-A triterpenoids were reported.