Higher fullerenes(C84,C90,C92,C94 and C96) were successfully isolated from the Soxhlet extract of the synthetical "Graphote Smokes" soot(GS sample) by using a big Cosmosil Buckysep(Phenomenex) column(250 mm × 10 mm) with a large injection.The fractions isolated have been determined by high performance liquid chro-matography(HPLC) and laser desorption mass spectrometry(LDMS).It is found that there are different fullerenes molecules in different fractions with retention time.The result indicates that fullerenes do exist in GS samples.Also,it excludes the suspicion to some extent that fullerene molecules might be generated by the laser desorption process in the LDMS.In addition,it also provides the experimental basis for the study of natural higher fullerenes and might be helpful to figure out the question if higher fullerenes do exist in the natural samples.
Pyrite framboids were found in the Permian-Triassic boundary at Meishan Section,while their sulfur isotopes were determined.The majority of framboids is less than 5μm in diameter,with some large-sized framboids.Also,euhedral gypsums were observed in the boundary clay.The authors suppose that most of the pyrite framboids formed just below the redox boundary and stopped growing after entering the lower water column.The result indicates that it was probably lower dysoxia condition in the temporal ocean.Moreover,the authors also presume that some pyrite was oxidated to sulfates accompanying the fluctuation of redox condition,which would probably be the origin of the negative sulfur isotopes of gypsum and CAS reported before.In addition,sulfur isotope of framboidal pyrite suggests that sulfur is originated from bacterial sulfate reduction in anoxic condition.Therefore, this study confirms that the ocean was widely anoxic during the Permian-Triassic transitional period. However,the redox condition in temporal ocean was probably not stable,with short-term fluctuations.
