Time-delayed 2-pulse studies of MALDI matrix ionization mechanisms

Individually subthreshold, time-delayed 355 nm laser pulses were used to investigate matrix-assisted laser desorption/ionization (MALDI) ion formation time scales for the matrix 2,5 dihydroxybenzoic acid. With 30 ps pulses, it was possible to identify a prompt, subnanosecond, mechanism and a slow, nanosecond, process involving at least two steps.