A method is provided increasing the useful dynamic range of an ion mobility spectrometry (IMS) or an IMS-mass spectrometry (IMS-MS) device. The method includes accumulating a first sample of ions over a first time interval; providing the first sample of ions to an ion detector to provide a first frame, accumulating a second sample of ions over a second time interval, where the second time interval is different than the first time interval, and providing the second sample of ions to the ion detector to provide a second frame. First data points of the first frame are selectively combined with second data points of the second frame to provide an accumulation frame of the first and second samples of ions.