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

Abstract

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.