Laser desorption-ionization time of flight mass spectrometry of various carbon materials

The possibilities of commercially available MALDI-TOF mass spectrometric instrumentation equipped with 337 nm nitrogen laser in carbon materials analysis have been examined. Laser desorption-ionization of synthetic diamond, graphite, glassy carbon, carbon nanotubes, and diamond-like thin layer results in the formation of two positively charged (C-n(+); n = 1-31 and odd-numbered 44-346) and one n negatively charged carbon cluster set (C-n(-); n = 1-19). Fullerene C-60 was analyzed for comparison. From the C clusters mass spectra, several similarities, concerning "magic number" ions with high signal intensities, can be observed. It is concluded that differing carbon materials are subjected by UV-Iaser pulses to similar physico-chemical changes. Heavy carbon clusters of low stability and characteristic loss of neutral C-3 particle in case of the smaller clusters during post-source decay (PSD) implies that the species observed do not possess stable fullerene structure, which might have been expected for C, species with n <= 20. (c) 2005 Elsevier Ltd. All rights reserved.