MATRIX-ASSISTED LASER DESORPTION IONISATION MASS-SPECTRA OF ANTIBIOTIC AND CRYPTAND COMPLEXES OF ALKALI-METAL IONS - A COMPARISON WITH ELECTROSPRAY-IONIZATION MASS-SPECTRA/

Matrix-assisted laser desorption/ionisation (MALDI) mass spectra of sa mples containing valinomycin and all of the alkali metal ions suggest that the relative concentrations of metal complexes in solution play a role in determining relative peak intensities. However, in analogous studies performed using three cryptand ligands the most intense peak f rom a metal complex in each case was that due to the lithium complex, indicating that MALDI is not a reliable guide to the metal ion selecti vities of this class of ligands.