Abstract:
Differential mobility spectrometry is performed under vacuum. Ions generated in a high pressure region are received from the inlet orifice of a vacuum chamber using a first ion guide located in the vacuum chamber. The first ion guide focuses the generated ions on a DMS device inlet end using a plurality of tapered electrodes. The DMS device is coaxial and adjacent to the first ion guide. The DMS device separates the focused ions using a plurality of electrodes. The inscribed diameter at the DMS device inlet end is larger than the inscribed diameter at the first ion guide exit end to maximize ion transfer. The separated ions are received from the DMS device using a second ion guide coaxial and adjacent to the DMS device. The second ion guide focuses the separated ions on an exit orifice of the vacuum chamber using a plurality of tapered electrodes.
Abstract:
A mass spectrometer is provided having an ion source for generating ions from a sample in a high pressure region, a first vacuum chamber having an inlet aperture, and an exit aperture. The at least one ion guide can be between the inlet and exit apertures and can include an entrance end and an exit end. The at least one ion guide can have a plurality of electrodes arranged around a central axis defining an ion channel, each of the plurality of electrodes being tapered, a planar surface of each of the plurality of tapered electrodes facing the interior of the at least one ion guide, and the surface gradually being narrowed and tilted inward to provide a smaller inscribed radius at the exit; and a power supply for providing an RF voltage to the at least one ion guide.
Abstract:
Ions are generated in a high pressure region and are passed into a vacuum chamber having an inlet and an exit aperture. The configuration of the inlet aperture and the pressure difference between the high pressure region and the vacuum chamber provides a supersonic free jet expansion that has a barrel shock of predetermined diameter. At least one ion guide is provided between the inlet and exit apertures having a predetermined cross-section defining an internal volume wherein the cross-section of the at least one ion guide is sized to be at least 50% of the predetermined diameter of the barrel shock of the supersonic free jet expansion. An RF voltage is provided to the at least one ion guide. Radial gas conductance is reduced in a first section of the at least one ion guide for damping shock waves resulting from the supersonic free jet expansion.
Abstract:
A mass spectrometer is provided having an ion source for generating ions from a sample in a high pressure region, a first vacuum chamber having an inlet aperture, and an exit aperture. The at least one ion guide can be between the inlet and exit apertures and can include an entrance end and an exit end. The at least one ion guide can have a plurality of electrodes arranged around a central axis defining an ion channel, each of the plurality of electrodes being tapered, a planar surface of each of the plurality of tapered electrodes facing the interior of the at least one ion guide, and the surface gradually being narrowed and tilted inward to provide a smaller inscribed radius at the exit; and a power supply for providing an RF voltage to the at least one ion guide.
Abstract:
Differential mobility spectrometry is performed under vacuum. Ions generated in a high pressure region are received from the inlet orifice of a vacuum chamber using a first ion guide located in the vacuum chamber. The first ion guide focuses the generated ions on a DMS device inlet end using a plurality of tapered electrodes. The DMS device is coaxial and adjacent to the first ion guide. The DMS device separates the focused ions using a plurality of electrodes. The inscribed diameter at the DMS device inlet end is larger than the inscribed diameter at the first ion guide exit end to maximize ion transfer. The separated ions are received from the DMS device using a second ion guide coaxial and adjacent to the DMS device. The second ion guide focuses the separated ions on an exit orifice of the vacuum chamber using a plurality of tapered electrodes.