An apparatus for mass spectrometry comprises a portion generator (10) for creating localized analyte portions in synchronization with trigger pulses, a transfer system (20) coupled to the portion generator (10) for transporting the localized analyte portions, a plasma ionizer unit (30) coupled to the transfer system (20) for atomizing, vaporizing and ionizing received analyte portions with plasma, a mass analyzer (41) coupled to the plasma ionizer unit (30) for analyzing received analyte portions, the mass analyzer (41) comprising at least one detector, and a data acquisition electronics (50) connected to the at least one detector for acquiring signals (43) generated by the at least one detector. The apparatus further includes a signal delay device (60) for receiving the trigger pulses (11) and delivering delayed signals (61) corresponding to the trigger pulses to account for a delay experienced by the particles to be analyzed between portion generation and detection.