Abstract: An apparatus for the collection of a chemical sample from the fingers of an individual for subsequent analytical analysis comprises a token having a base and a substrate on the base. The substrate defines an area such that when the token is removed from a token dispenser the fingers of the individual come into contact with the substrate. Sufficient force must be applied by the fingers of the individual to the substrate when the token is removed from the token dispenser that a chemical sample is transferred from the fingers of the individual to the substrate. The token is then presented for analysis. The substrate may be polytetrafluoroethylene or cotton. A token handler for use in association with the token and an analyzer is also disclosed. Additionally, a method of using the token to obtain a chemical sample from the fingers of an individual is disclosed.

Abstract: The gas pressure in an ion mobility spectrometer is controlled to maintain near-constant pressure in the drift region by adjusting gas flows in response to a pressure transducer output. The pressure in the system may be referenced to ambient pressure. The increase in pressure stability achieved permits the expected drift times of target analytes to be determined much more accurately than otherwise, and thereby allows more specific detection parameters to be used. This in turn results in a significantly improved false alarm rate for the device.

Abstract: There is provided an assembly for preferentially separating and collecting particles that are gathered from the surface of an article such as an item of baggage. The assembly features an impactor and a suction anvil that is displaceable from a collection medium. The anvil is displaceable from the collection medium so that the medium may be removed and analyzed for traces of substances such as explosives or narcotics. There is also provided, in combination with the assembly, a vacuum head and conduit for gathering the particles and a suction unit for creating the suction force. The collection medium containing collected particles is moved from the impactor to an analyzer by a stage movement device. The analyzer includes an analysis unit, such as an Ion Mobility Spectrometer, and a displaceable heater anvil.

Abstract: An ion mobility spectrometer for detecting substances such as narcotics and explosives, has inlets for a sample gas and a drift gas. The gas can be ambient air, bottled air, or another gas source. To ensure accuracy and prevent drifting of analyte peaks, the air is dried. A two stage dryer is provided comprising a first dryer, preferably a dryer which chills the air and removes water by condensation. This removes the bulk of the water. The second dryer includes a suitable absorbent, and reduces the water content to around 1-10 .mu.g/L, i.e. a level which will not substantially affect the performance of the IMS apparatus. The first dryer substantially reduces the load on the second dryer, and enables an extended period of use before the absorbent material in the second dryer either needs to be replaced or regenerated. The increased stability of calibrant and analyte peak positions allows detection windows to be narrowed, resulting in significantly lower false alarm rates.