Abstract: In a method for classifying and separating particles in a fluid stream in which the particles are sprayed and electrically charged and deflected in an electrical field one portion of the stream of the charged or ionized particles respectively is introduced into a first separation device operated as an analyzer (4) and is deflected under variation of the applied high voltage or the electric field respectively, whereby particles reach a detector chamber (10) according to separation criteria like, for example charge or particle size. This high voltage and/or field strength corresponding to a species collected in the detector chamber (10) is read and/or stored as a reference value. The particle stream is fed into a separator (5), in which the previously acquired high voltage and/or field strength is applied and particles of the species deflected in the analyzer (4) into the detector chamber (10) are enriched and discharged correspondingly.