Abstract: The methods herein provide for analysis of ion populations. Certain aspects include: obtaining a first data set that includes: a first binary On-OFF frequency sweep across a range of frequencies resulting in a first raw data in the time domain and obtaining a second data set that includes: a second binary On-OFF frequency sweep 180° out of phase from the first binary On-OFF frequency sweep so as to result in a second raw data in the time domain from received ion current resulting from the second binary On-OFF frequency sweep. Thereafter the two data sets are combined to provide for raw mobility signals of the ion populations in the time domain for each m/z over a range of selected m/z values. Additional aspects include a hybrid system for performing the methods disclosed herein.

Abstract: The methods herein provide for analysis of ion populations. Certain aspects include: obtaining a first data set that includes: a first binary On-OFF frequency sweep across a range of frequencies resulting in a first raw data in the time domain and obtaining a second data set that includes: a second binary On-OFF frequency sweep 180° out of phase from the first binary On-OFF frequency sweep so as to result in a second raw data in the time domain from received ion current resulting from the second binary On-OFF frequency sweep. Thereafter the two data sets are combined to provide for raw mobility signals of the ion populations in the time domain for each m/z over a range of selected m/z values. Additional aspects include a hybrid system for performing the methods disclosed herein.

Abstract: A method for selective detection of volatile and non-volatile explosives in a mass spectrometer or ion mobility spectrometer at a parts-per-quadrillion level without preconcentration is disclosed. The method comprises the steps of ionizing a carrier gas with an ionization source to form reactant ions or reactant adduct ions comprising nitrate ions (NO3?); selectively reacting the reactant ions or reactant adduct ions with at least one volatile or non-volatile explosive analyte at a carrier gas pressure of at least about 100 Ton in a reaction region disposed between the ionization source and an ion detector, the reaction region having a length which provides a residence time (tr) for reactant ions therein of at least about 0.

Abstract: A system and method are disclosed that provide selective detection of gas-phase target analytes at concentrations below 1 part-per-trillion including explosives, explosives compounds, and other threat agents involving chemical adduct ions between reactant ions and the target analytes for detection of the target analytes.

Abstract: An ion funnel trap is described that includes a inlet portion, a trapping portion, and a outlet portion that couples, in normal operation, with an ion funnel. The ion trap operates efficiently at a pressure of ˜1 Torr and provides for: 1) removal of low mass-to-charge (m/z) ion species, 2) ion accumulation efficiency of up to 80%, 3) charge capacity of ˜10,000,000 elementary charges, 4) ion ejection time of 40 to 200 ?s, and 5) optimized variable ion accumulation times. Ion accumulation with low concentration peptide mixtures has shown an increase in analyte signal-to-noise ratios (SNR) of a factor of 30, and a greater than 10-fold improvement in SNR for multiply charged analytes.

Abstract: Particular aspects provide novel methods for analysis of ion populations, the methods comprising filtering and selecting an ion population using a low-field dual-gate ion mobility spectrometer comprising a drift tube, the spectrometer operating at a pressure of at least 100 Torr, to provide mobility-selected ions. Certain aspects comprise: (i) subsequently accumulating the low-field selected ions in an ion trap (e.g., an MS ion trap) and mass spectrometry analysis; (ii) introducing the low-field selected ions into a high-field ion mobility spectrometer for separating thereby (optionally followed by mass spectrometry); and (iii) introducing the low-field selected ions into an ion trap mass spectrometer, and subsequently into a second low-field ion mobility spectrometer (e.g., a non-dual gate spectrometer operating at less than about 100 Torr). Additional aspects provide novel apparatus and combination thereof for performing the disclosed methods.