Ion mobility spectrometer, and method for analysing substances

An ion mobility spectrometer, comprising:

• at least one ion packet provision device configured to provide packets of ions in succession separated from one another at time intervals;
• an ion detector;
• at least one drift chamber through which ions from one or more of the packets of ions are guided over a predetermined distance in a drift direction to the ion detector, wherein the at least one drift chamber discharges the ions at the ion detector;
• and
• an ion modification area positioned between the ion packet provision device and the at least one drift chamber, wherein the ion modification area comprises an input electrode arrangement on a first the side facing toward the ion packet provision device and an output electrode arrangement on a second side facing toward the at least one drift chamber;
• and a modification chamber for receiving ions arranged between the input electrode arrangement and the output electrode arrangement, wherein the ion modification area is configured to carry out one or more modifications on the ions located in the modification chamber.