Application of sulfur as a matrix for laser desorption/ionization in the characterization of halogenated fullerenes

The application of sulfur as a matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) analysis of highly chlorinated and fluorinated fullerenes is reported. Control over fluorofullerene fragmentation which resulted in the domination of the molecular peak C(60)F(36)(-) was achieved, with the optimal matrix-to-analyte ratio found to be 1000:1. We suggest the possible mechanism of the molecular ion formation according to the charge transfer between the sulfur anions and C(60)F(36). For the first time the LDI and MALDI mass spectra of the highly chlorinated fullerene C(60)Cl(x)(x(max) approximately 32) are presented. The formation of odd chlorine ions (positive and negative) is observed. We conclude that use of sulfur as a matrix leads to a significant decrease in fragmentation of the halogenated fullerenes.