MALDI-TOF spectral analysis of C60 preparations. C60 was prepared in toluene (Panel A), in the water-soluble fullerene extracted from toluene (panel B) and in methanol (panel C). Representative aliquots of each preparation were analyzed by MALDI-TOF using α-cyano-4-hydroxycinnamic acid as the matrix. Spectra were acquired in the positive ion reflectron mode using the reflectron. The instrument was calibrated externally using a mixture of standard peptides (angiotensin II, 1046.54 Da; Substance P, 1347.736 Da; bombesin, 1619.823 Da; and ACTH clip 1–17, 2093.087 Da).