STUDIES ON THE SELECTION OF NEW MATRICES FOR ULTRAVIOLET MATRIX-ASSISTED LASER DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY/

A new group of compounds has been successfully tested as matrices for ultraviolet matrix-assisted laser desorption/ionization mass spectrome try (UV-MALDI MS). Several new matrices for UV-MALDI MS have been foun d by choosing, as potential matrices, compounds that perform an intram olecular proton transfer along an intramolecular H-bond under UV irrad iation. Compounds of this type are, for example, salicylamide, salicyl anilide, several ortho-hydroxyacetophenones and ortho-hydroxybenzophen ones. The matrix activity of these compounds is compared to the corres ponding meta- and para-isomers and to the matrix activity of such well known matrices as 2,5-dihydroxybenzoic acid and 2,4,6-trihydroxyaceto phenone. It was found that meta- and para-substituted hydroxycarbonyl compounds show either a significantly lower or no matrix activity comp ared with the ortho isomers.