Abstract: A method of mass spectrometry comprises the steps of ionizing the mixture of the sample and the matrix by repeated irradiation with primary particle beam pulses; introducing the produced ions into a mass analyzer and separating the ions with the mass analyzer according to their mass/charge ratios; detecting signals indicative of the number of the separated ions with an array detector; and integrating the detected signals during data collection periods in synchrony with the irradiation pulses of the primary particle beam. The data collection periods have a predetermined duration and predetermined start times relative to the primary particle beam pulses.