Matrix-enhanced cluster-SIMS

Abstract We have used 23 keV C60+ projectiles in the event-by-event bombardment and detection mode to investigate the emission of the gramicidin S [M − H]− ion embedded in a matrix of sinapic acid. We have observed an increase in the gramicidin S [M − H]− ion of approximately eight times by controlling the ratio of gramicidin S to sinapic acid. The maximum of the gramicidin S [M − H]− yield occurs at a matrix/analyte ratio of 10:1. This ratio is different from those typically used in matrix-assisted laser desorption/ionization.