Abstract: A mass spectrometer system including a device for supplying a protonated ion species; a single chamber having an entrance and an exit slit, the chamber receiving the supplied protonated ion and transmitting a reprotonated ion through the exit slit; a device for supplying a predetermined reagent gas within the chamber; a device for supplying an electron beam in said chamber such that the electron beam reacts with the supplied predetermined reagent gas to provide neutral reagent gas and protonated reagent gas within the chamber, the supplied ion species reacting with the neutral reagent gas to neutralize the ion species, thereby providing neutral species within the chamber, the neutral species reacting with the protonated reagent gas to provide reionized species within the chamber; and a device, coupled to the exit slit of the chamber, for extracting the reionized species.