Abstract: A time of flight mass spectrometer includes means for gating the flow of ions from the source to the detector with a modulation function, the frequency of which is swept. The detected ion current is obtained as a function of the ion current modulation frequency to derive an ion mass interferogram output in the frequency domain. The interferogram output is Fourier transformed from the frequency domain to the time domain to obtain a time of flight mass spectrum output in the time domain. The Fourier transform time of flight mass spectrometer provides increased duty cycle and signal-to-noise ratio for a given scan time.

Abstract: Methods and apparatus for time dispersive ion spectroscopy such as ion mobility spectroscopy. The methods include ionizing molecules of a sample and controllably admitting pulses of the resulting ions into a drift region. The drift region has an electric field therein which forces the admitted ions through the drift region. Ions emitted from the drift region during a gate open period simultaneous with the ion admission period are exclusively detected resulting in an ion detection signal. Data is recorded for the frequency rate at which the ion pulses are admitted to the drift region and the associated ion detector signal. The frequency of admitted ion pulses is scanned over a relevant range during which the ion admission period also varies. Data recorded for frequency and ion detection can be recorded and/or transformed such as by a Fourier transform to produce time dispersive spectra in the form of ion intensity or quantity as a function of the time period necessary for the ions to transit the drift region.

Abstract: A method and apparatus for resolving overlapped chromatographic peaks or other overlapped data obtained from operation of a differential migration apparatus used to analyze a substance whose composition is to be determined. The invention involves using a second analytical apparatus, such as a spectrometer, to supplement the data obtained from the basic differential migration apparatus. A multi-channel detector is used to monitor and record the various sets of data obtained from these apparatus. Data corresponding to regions of overlap identified by the apparatus are assembled in a measured data set. An estimated data set is then compiled describing the estimated migrational time behavior of each of a plurality of compounds present within the overlapped region. An identifying data set is then calculated based upon the estimated data set and the measured data set.