Because of their unusual electronic structures and properties,potential applications of fullerene pyrrolidine derivatives have attracted much interest in many fields,especially in materials science.In this study,eight fulleropyrrolidine derivatives were characterized by ion trap mass spectrometry(ESI IT-MS)under electrospray ionization condition.The obtained results showed that fullerene-N-methylpyrrolidine derivatives are readily ionized with the loss of one electron by negative-ion ESI IT-MS.Some fullerene-N-methyl pyrrolidine derivatives can be protonated with positive-ion ESI IT-MS or deprotonated with negative-ion ESI IT-MS when there are some groups or atoms in the molecular structure easy to catch or lose active hydrogen.The pyrrole ring of fulleropyrrolidine derivatives is easy to lose during the process of negative-ion ESI IT-MS/MS,and C60 can be observed in all the ESI IT-MS/MS spectra of fullerene pyrrolidine derivatives.Retro-cycloaddition reactions take place in the structure of the pyrrole ring to produce mono-substituted methanofullerene with the loss of CH2‖N—CH3.Useful informations about molecular weight and structure can be obtained by ESI-MS and ESI MS/MS.