Abstract: Disclosed herein is a method of and an apparatus for combined ion mobility and mass spectrometry analysis, the method comprising the following steps: introducing precursor ions (34) into a trap configured for trapping ions and for selectively ejecting trapped ions according to their m/z ratio, selectively ejecting precursor ions (34) having m/z values falling within at least one controllable ejection window from said trap (15), sequentially releasing precursor ions (34) from said IMS (16) according to their ion mobility, introducing said released precursor ions (34) into a mass filter (26) having a controllable mass window, fragmenting the precursor ions (34) transmitted through said mass filter (26) to generate fragment ions, and carrying out a mass spectrometry measurement on said fragment ions, wherein each fragment ion is associated with a mass window and an ion mobility (IM) range.