title: Generation of CsI cluster ions for mass calibration in matrix-assisted laser desorption/ionization mass spectrometry.
abstract: A simple method was developed for the generation of cesium iodide (CsI) cluster ions up to m/z over 20,000 in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). Calibration ions in both positive and negative ion modes can readily be generated from a single MALDI spot of CsI(3) with 2-[(2E)-3-(4-tert-butylphenyl)-2-methylprop-2-enylidene] malononitrile (DCTB) matrix. The major cluster ion series observed in the positive ion mode is [(CsI)(n)Cs](+), and in the negative ion mode is [(CsI)(n)I](-). In both cluster series, ions spread evenly every 259.81 units. The easy method described here for the production of CsI cluster ions should be useful for MALDI MS calibrations.
authors.affiliation: Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, Eindhoven, The Netherlands. x.w.lou@tue.nl
authors.forename: Xianwen
authors.initials: X
authors.lastname: Lou
authors.forename: Joost L J
authors.initials: JL
authors.lastname: van Dongen
authors.forename: E W
authors.initials: EW
authors.lastname: Meijer