ESI-MS is a soft ionization MS method newly developed, which can detect a sort of compounds existing as ions in solution. According to the capability of accepting electron of fullerenes, the mixtures of fullerenes in toluene may be determined directly by ESI-MS without pre-ionization. The negative-ion ESI mass spectra indicate that there have C60, C70, C76, C80, C82, C84, C86, C88, C90, C92, C94 and C96 in the mixture of fullerenes. The same results were obtained by pre-ionization using potassium-naphthalide as reducing agent. It indicated that the ability of accepting electron of fullerenes in the process of ESI-MS is the same as in the reaction process using potassium-naphthanlide as reducing agent.

Key words: FULLERENES, MASS SPECTRUM ANALYSIS