An apparatus for elemental analysis of particles such as single cells or single beads by mass spectrometry is described. The apparatus includes means for particle introduction; means to vaporize, atomize and ionize elements associated with a particle; means to separate the ions according to their mass-to-charge ratio; means to detect the separated ions, means to digitize the output of the means to detect the ions; means to transfer and/or to process and/or record the data output of the means to digitize, having means to detect the presence of a particle in a mass spectrometer; and means to synchronize one of the means for ion detection, data digitization, transfer, processing and recording with the means to detect the presence of a particle. Methods and computer readable code implementing aspects of the apparatus, and for reducing the rates of data generation, digitization, transfer, processing and recording are also described.