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

Abstract

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 nano-tubes, 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 negatively charged carbon cluster set ( C n - ; n = 1 – 19 ). Fullerene C 60 was analyzed for comparison. From the C n + 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-laser 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 n species with n ⩽ 20.