Abstract: Apparatus include a plurality of electrodes arranged in a sequence along a propagation axis between an ion inlet and an ion outlet to define an ion path and volume, wherein the electrodes are configured to receive respective voltages to produce an electric field in the volume that urges ions to propagate along the ion path downstream towards the ion outlet, wherein the sequence includes at least a first sequence portion including first and last electrodes configured to receive voltages according to a first function, and including at least one intermediate electrode situated between the first and last electrodes wherein the at least one intermediate electrode is configured to receive a voltage defining a voltage dip relative to the first function. Atmospheric flow tubes include a tube body and a central electrode configured to receive a time varying voltage configured to reduce a loss of the ions as the gas and ions flow along the flow tube volume to the flow tube outlet.

Abstract: A method is disclosed for detecting organophosphorus compounds and illicit drugs using an ion detector. A vapor sample containing at least one analyte and at least one dopant is ionized. A proton-bound adduct ion is formed between the analyte and the dopant in a reaction region defined between the ionization source and the ion detector.

Abstract: A method is disclosed for detecting organophosphorus compounds and illicit drugs using an ion detector. A vapor sample containing at least one analyte and at least one dopant is ionized. A proton-bound adduct ion is formed between the analyte and the dopant in a reaction region defined between the ionization source and the ion detector.

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: An enhanced swipe sampler and method of making are described. The swipe sampler is made of a fabric containing selected glass, metal oxide, and/or oxide-coated glass or metal fibers. Fibers are modified with silane ligands that are directly attached to the surface of the fibers to functionalize the sampling surface of the fabric. The swipe sampler collects various target analytes including explosives and other threat agents on the surface of the sampler.

Abstract: An enhanced swipe sampler and method of making are described. The swipe sampler is made of a fabric containing selected glass, metal oxide, and/or oxide-coated glass or metal fibers. Fibers are modified with silane ligands that are directly attached to the surface of the fibers to functionalize the sampling surface of the fabric. The swipe sampler collects various target analytes including explosives and other threat agents on the surface of the sampler.

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: A UV-LED photoemission ionization source and process are disclosed that provide ionization of analytes including volatile molecular species and organic residues for detection with various ion analyzers. The UV-LED source produces low-energy UV light (200 nm to 400 nm) that yields photoemission electrons from various conducting surfaces. These photoemission electrons provide direct and indirect ionization of analytes including trace organic residues without need of high electric fields.

Abstract: A UV-LED photoemission ionization source and process are disclosed that provide ionization of analytes including volatile molecular species and organic residues for detection with various ion analyzers. The UV-LED source produces low-energy UV light (200 nm to 400 nm) that yields photoemission electrons from various conducting surfaces. These photoemission electrons provide direct and indirect ionization of analytes including trace organic residues without need of high electric fields.