Abstract: An apparatus comprising an ion selecting device; an individual ion counter device; and an interface device integral with the ion selecting device and downstream of an ion separating chamber of the ion selecting device. The interface device comprises a tagging particle generator and a tagging chamber. Sample gas containing ions of a selected mobility enters the tagging chamber from the ion selecting device and is exposed to uncharged neutral tagging particles from the tagging particle generator. The ions collide with the tagging particles to form a mixture of tagged ions and uncharged neutral tagging particles which is then separated in a tagged ions separator forming part of the individual ion counting device before the separated tagged ions are counted.

Abstract: The invention provides an apparatus for increasing a number concentration of molecules of an analyte of interest in real time from a sample gas flow containing ionised molecules of the analyte, aerosol particles and other molecules, the apparatus comprising: an ion-concentrating chamber having: an inlet for receiving the sample gas flow; an ion outlet; and at least one other outlet; the ion-concentrating chamber being connected or connectable to a gas flow generating and controlling device for establishing a gas flow velocity field within the ion-concentrating chamber to direct the aerosol particles and other molecules of the sample gas flow to the at least one other outlet; and one or more electrodes arranged in an axially spaced apart manner along the ion-concentrating chamber for creating an electric field within the ion-concentrating chamber to direct the ionised analyte molecules in the sample gas flow to the ion outlet, wherein the electrodes are configured such that an absolute value of the stren

Abstract: The invention provides a method and apparatus subjecting an analyte in an ion concentrating chamber to an electric and velocity field to concentrate analyte ions into a smaller space.

Abstract: An apparatus comprising an ion selecting device; an individual ion counter device; and an interface device integral with the ion selecting device and downstream of an ion separating chamber of the ion selecting device. The interface device comprises a tagging particle generator and a tagging chamber. Sample gas containing ions of a selected mobility enters the tagging chamber from the ion selecting device and is exposed to uncharged neutral tagging particles from the tagging particle generator. The ions collide with the tagging particles to form a mixture of tagged ions and uncharged neutral tagging particles which is then separated in a tagged ions separator forming part of the individual ion counting device before the separated tagged ions are counted.

Abstract: The invention provides a method for increasing the number concentration of molecules of an analyte of interest in real time from a sample gas flow containing the analyte and other molecules; the method comprising: (a) when the analyte molecules of interest in the sample gas flow are non-ionised or are not ionised to a desired extent, exposing the sample gas flow to an ionising entity to bring about formation of ions of the analyte and then passing the sample gas flow through an ion-concentrating chamber; or (b) when the analyte molecules of interest in the sample gas flow are already ionised, passing the sample gas flow through an ion-concentrating chamber without first exposing the sample gas flow to an ionising entity; whereby, in the ion-concentrating chamber, analyte ions and other molecules are subjected to an electric field and a velocity field such that analyte ions are concentrated by the combined effects of the electric field and velocity field into a smaller space; wherein the ion-concentrating c

Abstract: The invention provides a device for extracting a vaporizable analyte from a sample gas containing the analyte and unwanted aerosol particles; the device comprising a vapour extraction chamber (2), first (3) and second (4) inlets, and first (5) and second (6) outlets; the vapour extraction chamber (2) being provided with or being linked to a heat source for heating the vapour extraction chamber (2) to a desired temperature to facilitate vaporization of analyte present in the sample gas; the first (3) and second (4) inlets being linked to an upstream end of the vapour extraction chamber (2) and the first (5) and second (6) outlets being linked to a downstream end of the extraction chamber (2); the first inlet (3) allowing a sample of gas containing the analyte and unwanted aerosol particles to be introduced into the vapour extraction chamber (2); the second inlet (4) being connected or connectable to a clean gas supply that does not contain the analyte or unwanted aerosol particles; the device being configur

Abstract: Apparatuses for increasing the effective size of gas-entrained particles in a particle detector are disclosed. In one embodiment, an apparatus comprises an evaporation chamber, a condenser in fluid communication with the evaporation chamber, and an inlet in fluid communication with the condenser for receiving a stream of sample gas containing gas-entrained particles. The evaporation chamber includes a heating element and a porous support surrounding the heating element. The porous support carries thereon a working fluid, and the heating element vaporizes the working fluid to form vapor within the evaporation chamber. The porous support may include a portion which extends into a working fluid reservoir.

Abstract: The invention provides a method of separating and collecting ions of a predetermined ion mobility from a gaseous mixture of ions of different ion mobilities using a differential mobility analyser apparatus, wherein the differential mobility analyser apparatus comprises an ion-separation chamber having: (a) a sample gas flow inlet; (b) a focusing chamber, an opening at one end of which serves as the sample gas flow inlet through which sample gas can flow into the ion-separation chamber; (c) a sheath gas inlet connected or connectable to a supply of sheath gas; (d) a sheath gas outlet; (e) an ion outlet through which the ions of predetermined ion mobility can be collected; and (f) two or more electrodes arranged to provide an ion-separating electric field across the ion-separation chamber; wherein the focusing chamber is oriented at an angle of from 30° to 90° relative to a direction of flow of the sheath gas along the ion-separation chamber; and wherein a focusing zone is provided in the focusing chamber,

Abstract: The invention provides a method of separating and collecting ions of a predetermined ion mobility from a gaseous mixture of ions of different ion mobilities using a differential mobility analyser apparatus, wherein the differential mobility analyser apparatus comprises an ion-separation chamber having: (a) a sample gas flow inlet; (b) a focusing chamber, an opening at one end of which serves as the sample gas flow inlet through which sample gas can flow into the ion-separation chamber; (c) a sheath gas inlet connected or connectable to a supply of sheath gas; (d) a sheath gas outlet; (e) an ion outlet through which the ions of predetermined ion mobility can be collected; and (f) two or more electrodes arranged to provide an ion-separating electric field across the ion-separation chamber; wherein the focusing chamber is oriented at an angle of from 30° to 90° relative to a direction of flow of the sheath gas along the ion-separation chamber; and wherein a focusing zone is provided in the focusing chamber,

Abstract: The invention provides an apparatus for increasing the size of gas-entrained particles in order to render the gas-entrained particles detectable by a particle detector, the apparatus comprising an evaporation chamber (2) and a condenser (7); the evaporation chamber (2) having an inlet (1) for admitting gas into the evaporation chamber and an outlet through which vapour-laden gas may leave the evaporation chamber; the evaporation chamber (2) having disposed therein a heating element (3) and a porous support (6), the heating element being in direct contact with the porous support, wherein the porous support (6) carries thereon a vaporisable substance and the heating element (3) is heatable to vaporise the vaporisable substance to form vapour within the evaporation chamber (2); the condenser (2) being in fluid communication with the outlet of the evaporation chamber, and the condenser (7) having an outlet for connection to the particle detector.

Abstract: The invention provides a method for obtaining aerosol particle size distributions with a scanning mobility particle sizer (SMPS) device comprising a differential mobility analyzer (DMA); which method comprises the stages: (i) collecting a first data set of particle concentrations vs. size for a size range from a predetermined minimal size Dmin to an intermediate size Dt by varying a voltage applied to a DMA column of an SMPS from Vmin to Vt1 at a first sheath flow rate Qsh1; (ii) changing the sheath flow rate from the first sheath flow rate Qsh1 to a second sheath flow rate Qsh2; (iii) collecting a second data set of particle concentrations vs.

Abstract: The invention provides a method for obtaining aerosol particle size distributions with a scanning mobility particle sizer (SMPS) device comprising a differential mobility analyzer (DMA); which method comprises the stages: (i) collecting a first data set of particle concentrations vs. size for a size range from a predetermined minimal size Dmin to an intermediate size Dt by varying a voltage applied to a DMA column of an SMPS from Vmin to Vt1 at a first sheath flow rate Qsh1; (ii) changing the sheath flow rate from the first sheath flow rate Qsh1 to a second sheath flow rate Qsh2; (iii) collecting a second data set of particle concentrations vs.

Abstract: The invention provides an apparatus set up for diluting aerosols; the apparatus comprising: (i) a dilution chamber (1); (ii) an aerosol inlet (2) on one side of the dilution chamber for admitting an aerosol into the dilution chamber; (iii) an aerosol outlet (3) on the same or another side of the dilution chamber through which diluted aerosol particles can leave the dilution chamber; (iv) a diluent gas inlet (4) for admitting into the chamber a diluent gas; (v) a diluent gas outlet (5) through which diluent gas can leave the dilution chamber; (vi) a gas flow maintenance system (6) that provides circulation of the diluent gas through the dilution chamber; and (vii) means for determining the extent of dilution of the aerosol leaving the aerosol outlet. The invention also provides methods of diluting and counting aerosol particles using the apparatus of the invention.

Abstract: The invention provides an apparatus for charging or altering the charge of gas-entrained particles in an aerosol, the apparatus comprising: (a) an ion generating chamber (1) containing a first electrode (2) for generating a corona discharge, the first electrode (2) being connected to a power supply of sufficiently high voltage to create the corona discharge; the ion generating chamber (1) having an ion outlet (10) through which ions generated by the corona discharge can leave the chamber (1); (b) a particle charging chamber (5) in which charging or altering the charge of gas-entrained particles in an aerosol takes place, the particle charging chamber (5) being in fluid communication with the ion generation chamber (1) and having an inlet and an aerosol outlet; and (c) an electrically non-conductive interface body (7) positioned between the aerosol particle charging chamber (5) and the ion generating chamber (1), the interface body (7) having a hollow interior which is in fluid communication with the ion gen

Abstract: The invention provides an apparatus for increasing the size of gas-entrained particles in order to render the gas-entrained particles detectable by a particle detector, the apparatus comprising an evaporation chamber (2) and a condenser (7); the apparatus is configured so that vapour-laden gas from the evaporation chamber can flow into the condenser and condensation of the vaporisable substance onto gas-entrained particles in the condenser takes place to increase the size of the particles so that they are capable of being detected by a particle detector.

Abstract: The invention provides an apparatus for increasing the size of gas-entrained particles in order to render the gas-entrained particles detectable by a particle detector, the apparatus comprising an evaporation chamber (2) and a condenser (7); the apparatus is configured so that vapour-laden gas from the evaporation chamber can flow into the condenser and condensation of the vaporisable substance onto gas-entrained particles in the condenser takes place to increase the size of the particles so that they are capable of being detected by a particle detector.

Abstract: A nanoparticle size classifier comprising a variable flow rate system with a single diffusion element 3 placed inside a cell 2 containing inlet 1 and outlets 6 and 7, an aerosol filter 8, flow meter 9, pump 10 and pump controller 11, which enables a plurality of measurements to be obtained by means of passing an aerosol through the diffusion element 3 at various flow rates. Preferably, outlet of the diffusion cell is connected to a particle counter 5 via a three-way valve 6. The diffusion element has a net or screen that permit air through but capture some particles. In a preferred embodiment, the nanoparticle size classifier is connected to a PC 12 (a notebook or a palm-size computer) to acquire and process data.

Abstract: The invention provides an apparatus for increasing the size of gas-entrained particles in order to render the gas-entrained particles detectable by a particle detector, the apparatus comprising an evaporation chamber (2) and a condenser (7); the apparatus is configured so that vapour-laden gas from the evaporation chamber can flow into the condenser and condensation of the vaporisable substance onto gas-entrained particles in the condenser takes place to increase the size of the particles so that they are capable of being detected by a particle detector.

Abstract: A nanoparticle size classifier comprising a variable flow rate system with a single diffusion element 3 placed inside a cell 2 containing inlet 1 and outlets 6 and 7, an aerosol filter 8, flow meter 9, pump 10 and pump controller 11, which enables a plurality of measurements to be obtained by means of passing an aerosol through the diffusion element 3 at various flow rates. Preferably, outlet of the diffusion cell is connected to a particle counter 5 via a three-way valve 6. The diffusion element has a net or screen that permit air through but capture some particles.

Abstract: Ions in a steady flow sample are counted by colliding the ions in a mixing chamber with a numerical excess of uncharged or neutral aerosol particles, suitably glycerol, entrained in air, to transfer respective charges from the ions to charge individual aerosol particles and passing the gases through a separating chamber subjected to an electric field to direct the charged aerosol particles to impinge upon an optical particle counter.