Ion Mobility Spectrometry

Abstract

1. An ion mobility spectrometer having a drift region (20) and the reaction region (5), characterized in that it is arranged to dope the reaction region (5) reaction without doping the drift region (20) and comprises at least two working selectively modifier (30 and 31) of ions arranged one after another along the trajectory of ions such that at least one of them when working removes the adducts of doping ions. ! 2. A spectrometer according to claim 1, characterized in that at least one of the modifiers (30, 31) of ions is adapted to generate an electric field sufficiently strong to fragment ions. ! 3. A spectrometer according to claim 1, characterized in that at least one of the ion modifiers is configured to increase the temperature to a level sufficient to fragment ions. ! 4. Spectrometer according to any one of claims 1-3, characterized in that it comprises a channel (32) for flow of filtered gas through the drift region (20) to remove therefrom any dopant. ! 5. Spectrometer according to any one of claims 1-3, characterized in that it comprises a circuit (8) for supplying alloying dopant vapor to the reaction region (5) close to the drift region (20) and removal of the dopant vapor at the opposite end of the reaction region (5) to a dopant coming out of the drift region (20). ! 6. Spectrometer according to any one of claims 1-3, characterized in that it comprises an electrostatic gate (21) situated between the reaction region (5) and the drift region (20). ! 7. Spectrometer according to any one of claims 1-3, characterized in that it is adapted to control the modifiers (30, 31) of ions in response to the detected