The gas-phase basicities of three common matrices used in matrix-assisted laser desorption/ionization (MALDI) have been investigated using laser desorption with Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. In bracketing type experiments, laser- desorbed ions from 2,5-dihydroxy-benzoic acid, α-cyano-4-hydroxy-cinnamic acid and sinapic acid were tested for their ability to protonate test substances. This study was not limited to protonated matrix species but also included prominent fragments.

Keywords: MALDI, FT-ICR, proton affinity, fragmentation, matrix