A nebulizer for a charged aerosol detection (CAD) system is disclosed. The nebulizer is provided with a spray emitter for generating a spray of droplets within a central region of a spray chamber. The central region is separated from an upper region by a horizontally projecting rib, which defines a passageway between the central and upper regions. The major direction of droplet travel within the upper region is substantially reversed with respect to the major direction of droplet travel within the central region. Larger droplets are unable to negotiate the turn from the central to upper regions and impinge on a rear surface of the spray chamber. Removal of larger droplets has the advantageous effect of enabling the detector to sense a smaller range of particle sizes, which establishes a relatively steady electrical current at the detector.

The invention relates to a method and the device which is required for its performing for the determination of the isotope ratio of carbon and/or nitrogen in an aqueous mobile phase which contains a sample. The method comprises the following steps: introduction of the aqueous mobile phase into a reactor (i), heating of the aqueous mobile phase with addition of oxygen in the reactor to a temperature of higher than 600° C. for the formation of a water containing sample gas (ii), reduction of the nitrogen oxides being present in the sample gas as well as removal of the contained oxygen (iii), removal of water from the sample gas by chemical drying and/or membrane gas drying (iv) and introduction of the dried sample gas into an isotope mass spectrometer (v). It is essential for the present invention that the introduction in step (i) is realized by introducing the aqueous mobile phase in a capillary tube which leads into the reactor with a gas mixture of oxygen and at least one inert gas, wherein the mass flow of oxygen and inert gas is regulated or controlled by at least one mass flow controller which is upstream with respect to the introduction and that after step (iv) removed water is actively pumped off.

A nebulizer for a charged aerosol detection (CAD) system is disclosed. The nebulizer is provided with a spray emitter for generating a spray of droplets within a central region of a spray chamber. The central region is separated from an upper region by a horizontally projecting rib, which defines a passageway between the central and upper regions. The major direction of droplet travel within the upper region is substantially reversed with respect to the major direction of droplet travel within the central region. Larger droplets are unable to negotiate the turn from the central to upper regions and impinge on a rear surface of the spray chamber. Removal of larger droplets has the advantageous effect of enabling the detector to sense a smaller range of particle sizes, which establishes a relatively steady electrical current at the detector.

A nebulizer for a charged aerosol detection (CAD) system is disclosed. The nebulizer is provided with a spray emitter for generating a spray of droplets within a central region of a spray chamber. The central region is separated from an upper region by a horizontally projecting rib, which defines a passageway between the central and upper regions. The major direction of droplet travel within the upper region is substantially reversed with respect to the major direction of droplet travel within the central region. Larger droplets are unable to negotiate the turn from the central to upper regions and impinge on a rear surface of the spray chamber. Removal of larger droplets has the advantageous effect of enabling the detector to sense a smaller range of particle sizes, which establishes a relatively steady electrical current at the detector.