Possible precursor of perylene in sediments of Lake Biwa elucidated by stable carbon isotope composition

We determined the stable carbon isotope compositions (δ13C values) of perylene and compounds coexisting with it to elucidate the precursor of perylene in sediments of Lake Biwa. Although we found a high amount of friedelin (6.5 μg g-1) in extracts, originating mainly from C3 angiosperms, its δ13C value (-30.8‰±0.1‰) was different from that of perylene (-27.8‰±0.3‰). The δ13C values of friedelin and perylene lay within the ranges for Japanese angiosperms (C3, -37.5‰ to -28.6‰) and gymnosperms (C3, -28.3‰ to -26.0‰), respectively. Since these values were clearly more negative than those of Japanese aquatic plants (C3, -16.5‰ to -14.6‰), it can be considered that the perylene originated from the land, principally from gymnosperms.