Abstract: A device to assist with the insertion of a nasal bridle includes an insertion guide and an introducer that is attached to bridle tape. The guide is switchable between two configurations: a substantially straight configuration and a second configuration in which an exit aperture at an upper end of the guide is either at a downwardly oriented angle and/or displaced laterally from the guide longitudinal axis, for example by causing the upper end of the guide to adopt a u-bend. The guide is inserted into a nostril while straight and then adopts its second configuration. The introducer is pushed through the guide and, at the exit, is guided beyond the septum into and out of the opposite nostril. Introducer and tape are pulled through the nasal passage before removing the guide. The guide therefore ensures that introducer and tape are held clear of the septum, reducing discomfort.

Abstract: A detecting method using an IMS apparatus with a preconcentrator outside its inlet aperture. Analyte vapor is adsorbed during a first phase when substantially no gas is admitted to the reaction region. The preconcentrator is then energized to desorb the analyte molecules and create a volume of desorbed molecules outside the IMS housing. Next, a pressure pulser is energized momentarily to drop pressure in the housing and draw in a small sip of the analyte molecules from the desorbed volume through the aperture. This is repeated until the concentration of analyte molecules in the desorbed volume is too low for accurate analysis, following which the apparatus enters another adsorption phase.

Abstract: A device to assist with the insertion of a nasal bridle includes an elongated insertion guide made of flexible resilient material. The guide includes an exit aperture at its upper end and is switchable between two configurations. In a first configuration, the guide is substantially straight enabling it to be more easily passed into or removed from a nasal cavity. In a second configuration, the exit aperture is either at a downwardly oriented angle and/or displaced laterally from the guide longitudinal direction, for example by causing the upper end of the guide to adopt a u-bend. This enables an introducer, attached to nasal bridle tape, to be passed through the guide and guided beyond the septum and into the opposite nostril. The introducer is then pulled through the nasal passage, with the bridle tape following. The bridle tape may then be used to secure a feeding tube.

Abstract: IMS apparatus has an inlet with a preconcentrator opening into a reaction region where analyte molecules are ionized and passed via a shutter to a drift region for collection and analysis. A pump and filter arrangement supplies a flushing flow of clean gas to the housing in opposition to ion flow. A pressure pulser connects with the housing and is momentarily switched to cause a short drop in pressure, in the housing to draw in a bolus of analyte sample from the preconcentrator. Just prior to admitting a bolus of sample, the pump is turned off so that the flushing flow drops substantially to zero, thereby prolonging the time the analyte molecules spend in the reaction region.

Abstract: An ion mobility spectrometer has a pair of electrodes and midway along the drill chamber. A high field is applied between the electrodes and sufficient to modify ions in the region of the electrodes such that they move at a different rate towards the collector plate. This is used to modify the time of flight of selected ions or ion clusters and enable identification of ambiguous peaks on the IMS spectrum.

Abstract: A detecting method using an IMS apparatus with a preconcentrator outside its inlet aperture. Analyte vapor is adsorbed during a first phase when substantially no gas is admitted to the reaction region. The preconcentrator is then energized to desorb the analyte molecules and create a volume of desorbed molecules outside the IMS housing. Next, a pressure pulser is energized momentarily to drop pressure in the housing and draw in a small sip of the analyte molecules from the desorbed volume through the aperture. This is repeated until the concentration of analyte molecules in the desorbed volume is too low for accurate analysis, following which the apparatus enters another adsorption phase.

Abstract: An IMS system or the like has dopant contained in a way such that it is only released when needed. The dopant could be contained in a device (50) similar to an ink-jet printer and released as droplets (55) when required. Alternatively, the dopant could be trapped in material (156) of a molecular sieve (150) in such a way that it is not normally released into air flowing through the sieve but can be released by energizing a heater (157) in the sieve.

Abstract: An IMS or other analytical instrument has a corona discharge needle (20) to ionize sample gases or vapours. A gate (3) is opened or closed to admit or prevent entry of the ions produced by the corona discharge to a drift chamber (4). The operation of the corona discharge needle (20) and the gate (3) are controlled such that the gate is open during at least two discharges, to admit faster ions produced by the most recent discharge together with slower ions produced by an earlier discharge.

Abstract: A vapor generator system (1, 101) for an IMS (4, 104) or other apparatus has a chamber (9, 109) in which vapor is produced. A fan or other flow generator (6, 106) is connected to an inlet (8, 108) of the vapor chamber (9, 109) and its outlet (13, 113) is connected to an adsorbent passage (14, 114), such as formed by a bore through a block (15) of carbon. When the fan (6, 106) is on gas flows through the vapor chamber (9, 109) and the adsorbent passage (14, 114) to the IMS (4, 104) or other outlet, with little vapor being adsorbed in the passage. When the fan (6, 106) is off, any vapor molecules that escape to the adsorbent passage (14, 114) do so at a low rate such that substantially all is adsorbed and no vapor escapes.

Abstract: A field asymmetric ion mobility spectrometer (FAIMS) has an analyte ion source assembly by which an analyte substance is ionized and supplied to the inlet of the spectrometer. The ion source assembly has an upstream source of clean, dry air and two ion sources of opposite polarity arranged at the same distance along the flow path. The ion sources are arranged so that the overall charge of the plasma produced is substantially neutral. The analyte substance is admitted via an inlet downstream of the ion sources and flows into a reaction region of enlarged cross section to slow the flow and increase the time for which the analyte molecules are exposed to the plasma.

Abstract: IMS apparatus has a preconcentrator outside its inlet aperture. Analyte vapor is adsorbed during a first phase when substantially no gas is admitted to the reaction region. The preconcentrator is then energized to desorb the analyte molecules and create a volume of desorbed molecules outside the IMS housing. Next, a pressure pulser is energized momentarily to drop pressure in the housing and draw in a small sip of the analyte molecules from the desorbed volume through the aperture. This is repeated until the concentration of analyte molecules in the desorbed volume is too low for accurate analysis, following which the apparatus enters another adsorption phase.

Abstract: IMS apparatus has an inlet with a preconcentrator opening into a reaction region where analyte molecules are ionized and passed via a shutter to a drift region for collection and analysis. A pump and filter arrangement supplies a flushing flow of clean gas to the housing in opposition to ion flow. A pressure pulser connects with the housing and is momentarily switched to cause a short drop in pressure, in the housing to draw in a bolus of analyte sample from the preconcentrator. Just prior to admitting a bolus of sample, the pump is turned off so that the flushing flow drops substantially to zero, thereby prolonging the time the analyte molecules spend in the reaction region.

Abstract: IMS apparatus has an inlet with a preconcentrator opening into a reaction region where analyte molecules are ionized and passed via a shutter to a drift region for collection and analysis. A pump and filter arrangement supplies a flushing flow of clean gas to the housing in opposition to ion flow. A pressure pulser connects with the housing and is momentarily switched to cause a short drop in pressure, in the housing to draw in a bolus of analyte sample from the preconcentrator. Just prior to admitting a bolus of sample, the pump is turned off so that the flushing flow drops substantially to zero, thereby prolonging the time the analyte molecules spend in the reaction region.

Abstract: A detection system comprises a housing having a sample inlet and a gas outlet, and a preconcentrator. The preconcentrator can include a microelectromechanical system (MEMS) configured to accumulate or release a dopant at selected times, and can be located inside or outside the housing. The detection system can include an ion mobility spectrometer, a mass spectrometer, or a combination thereof. A method of analyzing a substance comprises supplying a sample gas or vapor comprising the substance, accumulating a dopant in a first preconcentrator, releasing the dopant at selected times from the preconcentrator to an area containing the sample, ionizing the substance to generate detectable species, separating the detectable species, and determining the detectable species by a detection unit. The system and method allow the rapid introduction and removal of dopant to facilitate fast and accurate identification of the sample.

Abstract: An ion mobility spectrometer has a pair of electrodes and midway along the drift chamber. A high field is applied between the electrodes and sufficient to modify ions in the region of thee electrodes such that they move at a different rate towards the collector plate. This is used to modify the time of flight of selected ions or ion clusters and enable identification of ambiguous peaks on the IMS spectrum.

Abstract: An ion mobility spectrometer has two drift chambers and a common, doped reaction region. Each drift chamber includes an ion modifier, such as one that fragments the doped ions by a high electrical field. One of the drift chambers is doped and the other is undoped. In this way, the dopant adducts are removed by the modification process but then recombine with dopant only in the doped chamber so that different outputs are produced by the two drift chambers.

Abstract: A field asymmetric ion mobility spectrometer (FAIMS) has an analyte ion source assembly by which an analyte substance is ionized and supplied to the inlet of the spectrometer. The ion source assembly has an upstream source of clean, dry air and two ion sources of opposite polarity arranged at the same distance along the flow path. The ion sources are arranged so that the overall charge of the plasma produced is substantially neutral. The analyte substance is admitted via an inlet downstream of the ion sources and flows into a reaction region of enlarged cross section to slow the flow and increase the time for which the analyte molecules are exposed to the plasma.

Abstract: A field asymmetric ion mobility spectrometer (FAIMS) has an analyte ion source assembly by which an analyte substance is ionized and supplied to the inlet of the spectrometer. The ion source assembly has an upstream source of clean, dry air and two ion sources of opposite polarity arranged at the same distance along the flow path. The ion sources are arranged so that the overall charge of the plasma produced is substantially neutral. The analyte substance is admitted via an inlet downstream of the ion sources and flows into a reaction region of enlarged cross section to slow the flow and increase the time for which the analyte molecules are exposed to the plasma.

Abstract: A vapour generator system (1, 101) for an IMS (4, 104) or other apparatus has a chamber (9, 109) in which vapour is produced. A fan or other flow generator (6, 106) is connected to an inlet (8, 108) of the vapour chamber (9, 109) and its outlet (13, 113) is connected to an adsorbent passage (14, 114), such as formed by a bore through a block (15) of carbon. When the fan (6, 106) is on gas flows through the vapour chamber (9, 109) and the adsorbent passage (14, 114) to the IMS (4, 104) or other outlet, with little vapour being adsorbed in the passage. When the fan (6, 106) is off, any vapour molecules that escape to the adsorbent passage (14, 114) do so at a low rate such that substantially all is adsorbed and no vapour escapes.

Abstract: An IMS detector has a pin-hole or capillary inlet having a coating of an adsorbent material, such as polydimethylsiloxane, which is adsorbent to an analyte substance of interest. The analyte is adsorbed into the material until a heater is energized to heat the adsorbent material and release the adsorbed analyte substance for detection in a detector.