Matrix-assisted laser desorption ionization using lithium-substituted mordenite surface

An efficient matrix for matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) has been developed. The use of 2,4,6-trihydroxyacetophenone (THAP) on lithium-substituted zeolite has enabled ionization of low-molecular-weight compounds that are not detectable by conventional MALDI-MS. IR measurements and quantum-chemical calculations have also been carried out to understand the adsorption structure of THAP on zeolite. The mechanism of Li+ adduction from zeolite to THAP is also discussed. The important role of the water molecules adsorbed on the zeolite surface for the Li+ adduction from zeolite to THAP has been clarified. (C) 2012 Elsevier B.V. All rights reserved.