Two-step-method extraction of endohedral metallofullerenes

A new and efficient extraction method of endohedral metallofullerenes, especially of rare-earth elements encapsulated metallofullerenes, has been reported in this paper. Soxhlet-extraction of raw soot with toluene was used in the first step to wash away most accompanying C-60, C-70. Then pyridine was chosen as solvent to obtain high-temperature and high pressure extract. Two kinds of extract were analysed by DEI-MS and LDI-MS, the results indicate that this two-step method can provide the extract which has the highest fraction of endohedral metallofullerenes. So it will greatly simplify the following separation and purification processes of metallofullerenes.