Neutral/Ion reactor in adiabatic supersonic gas flow for ion mobility time-of-flight mass spectrometry

A method of analyzing gaseous ions, neutral species or mixtures of ions and neutral species comprising:

• introducing said ions and/or neutral species into a gas flow formation region to form a gas flow of said ions and/or neutral species, said gas flow formation region comprising a sectioned capillary having at least two electrodes;
• introducing said gas flow of ions and/or neutral species into at least one sectioned radio-frequency multipole ion guide, said sectioned ion guide comprising a plurality of electrically isolated electrode sections;
• applying voltage selected from the group consisting of DC voltages, AC voltage, RF voltages, and any combination thereof, to one or more sections of said at least one sectioned radio-frequency multipole ion guide, wherein said step of applying voltage to said multipole ion guide comprises producing a resonant rotating field which extracts specific ions from said gas flow and causes said specific ions to follow a rotational orbit around the central axis of said multipole ion guide;
• and
• detecting said gas flow of ions and/or neutral species.