Partial separation of fullerenes by gradient sublimation

An experimental technique is investigated to separate/enrich fullerenes of metallofullerenes, exploiting differences in sublimation temperatures without the use of solvents. Fullerenes are sublimed out of the soot and deposited on a quartz rod along a temperature gradient (gradient sublimation). In a position-sensitive experiment the composition of the deposit on the rod is monitored by laser-desorption mass spectrometry. Strongly enriched regions containing specific fullerene molecules (i.e., C[sub 84] or LaC[sub 82]) are observed. Furthermore, C[sub 74], which could not be extracted from the soot by organic solvents, sublimes out of the soot. 26 refs., 6 figs.