Time-resolved fluorescence and mass spectroscopic measurements were carried out for 2,4,6-trihydroxyacetophenone, one of the typical organic matrix molecules for matrix-assisted laser desorption ionization (MALDI), on a zeolite surface to understand the correlation between the electronic relaxation lifetime of matrix molecules and their fragmentation peaks on mass spectra. It has been clarified that fast relaxation of the excess vibrational energy stored in the matrix molecules to the surrounding media after the photoexcitation is important to prevent the dissociation of the matrix molecules. (C) 2012 Elsevier B.V. All rights reserved.