Effective methods for the measurement of CsI cluster ions using MALDI‐MS with suitable solvent combinations and additives

A method to measure CsI cluster ions ((CsI)_nCs⁺, (CsI)_nI^?) from CsI samples in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) was developed with a 2‐(2E)‐3‐(4‐tert‐butylphenyl)‐2‐methylprop‐2‐enylidene] malononitrile (DCTB) matrix and additives. Solvent combinations in which the CsI and DCTB solutions were miscible were effective in detecting CsI cluster ions at a mass range of over m/z 2000 and are associated with a characteristic spread of DCTB within the CsI/DCTB mixture. The addition of saccharides or sugar alcohols to the CsI/DCTB mixture improved the DCTB distribution and widened the mass distribution of CsI cluster ions up to m/z 10 000 in the linear mode. Copyright © 2014 John Wiley & Sons, Ltd.