title: Application and evaluation of solvent-free matrix-assisted laser desorption/ionization mass spectrometry for the analysis of derivatized fullerenes.
abstract: A variety of derivatized fullerenes have been studied by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. Of particular emphasis has been the evaluation of a recently introduced solvent-free sample/target preparation method. Solvent-free MALDI is particularly valuable in overcoming adverse solvent-related effects, such as insolubility and/or degradation of the sample. The method was applied to fullerene derivatives susceptible to decomposition under insufficiently "soft" MALDI conditions. Analytes included the hydrofullerene: C(60)H(36), fluorofullerenes: C(60)F(x) where x = 18, 36, 46, 48 and C(70)F(x) where x = 54, 56, methano-bridged amphiphilic ligand adducts to C(60) and the [4 + 2] cycloadduct of tetracene to C(60). The new solvent-free sample preparation is established as an exceedingly valuable addition to the repertoire of preparation protocols within MALDI. The MALDI mass spectra were of very high quality throughout, providing a testimony that "soft" MALDI conditions could be achieved. Using the [4 + 2] cycloadduct of tetracene to C(60) as the model analyte for direct comparison with solvent-based MALDI, the solvent-free approach led to less fragmentation and more abundant analyte ions. Applying solvent-free sample preparation, different matrix compounds have been examined for use in the MALDI of derivatized fullerenes, including sulfur, tetracyanoquinodimethane (TCNQ), 9-nitroanthracene (9-NA) and trans-2-[3-(4-tert-butylphenyl)-2-methyl-2- propenylidene]malononitrile (DCTB). DCTB was confirmed as the best performing matrix, reducing unwanted decomposition and suppression effects.
authors.affiliation: Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK.
authors.forename: Sotirios G
authors.initials: SG
authors.lastname: Kotsiris
authors.forename: Yury V
authors.initials: YV
authors.lastname: Vasil'ev
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Streletskii
authors.forename: Ming
authors.initials: M
authors.lastname: Han
authors.forename: Lewis P
authors.initials: LP
authors.lastname: Mark
authors.forename: Olga V
authors.initials: OV
authors.lastname: Boltalina
authors.forename: Nikos
authors.initials: N
authors.lastname: Chronakis
authors.forename: Michael
authors.initials: M
authors.lastname: Orfanopoulos
authors.forename: Hartmut
authors.initials: H
authors.lastname: Hungerbühler
authors.forename: Thomas
authors.initials: T
authors.lastname: Drewello