Abstract: A fluid sampling system has a drift cell (60) enclosing a first fluid. An inlet chamber (62) communicates with the body of first fluid via an orifice (74). A series of negative pressure pulses is applied to the first fluid, causing a sample of a second fluid to be drawn in through the orifice (74). The sample is then entrained into the air flow of a closed loop circulatory system and is detected or measured by an ion mobility spectrometer. A second chamber may be linked to the first chamber, with the negative pressure pulses provided by the second chamber.

Abstract: A fluid sampling system has a fluid enclosing element, such as drift cell (60), enclosing a volume of a first fluid. A body of a second fluid, for example in an inlet chamber (62), communicates with the body of first fluid via a small orifice (74). A series of negative pressure pulses is applied to the first fluid by an electromechanical transducer (92), each negative pulse causing a sample of the second fluid to be drawn in through the orifice (74). The sample is then entrained into the air flow of a closed loop circulatory system, and can be detected or measured by any appropriate equipment such as an ion mobility spectrometer.

Abstract: A drift chamber for an ion mobility spectrometer includes an array of conductive electrodes (12, 14, 16, 18) mounted upon a common insulating substrate (10) such as a printed circuit board. The printed circuit board may also form one side of a rectangular enclosure (24), thus allowing the drift chamber to be substantially smaller than previously. The printed circuit board may have a track (60) around its periphery to which the rectangular enclosure (24) can be attached, thus creating a gas-tight seal.

Abstract: A method and apparatus for detecting the presence of vapor-producing substances such as explosives contained within an item of baggage, in which the item of baggage is enclosed in a chamber and the air pressure in the chamber is varied cyclically in order to mix at least a portion of the air in the item of baggage with that in the chamber. A vapor detector is then used to detect the presence in the chamber air of vapors given off by an explosive substance or drug (e.g., cannabis) contained within the item of baggage.