Certain embodiments described herein are directed to rod assemblies such as, for example, quadrupole, hexapole and octupole rod assemblies. In some instances, the rod assemblies include at least one pole comprising an integral fluid path configured to fluidically couple an ion volume formed by the assembly to an outer volume of the assembly to remove fluid within the ion volume to the outer volume while containing ions of a selected mass-to-charge range.

A high-voltage power source for applying high voltage to a nozzle of an ESI ion source includes a charge release assistant section (26) including switch circuits (62 and 65) and other elements for forcing electric charges accumulated at output terminals to be discharged in a polarity-switching operation, whereby the positive/negative switching of the polarity of the output voltage can be quickly performed. In the mass spectrometer according to the present invention, for example, when the voltage applied to the nozzle needs to be changed from Vi to V.sub.2 (where V.sub.1 and V.sub.2 are positive, and V.sub.1>V.sub.2), a voltage control section (20) under the command of a main controller (9) operates a positive voltage generation section (21) and negative voltage generation section (23) so as to temporarily provide a negative output voltage. After a predetermined period of time, the voltage control section operates the positive voltage generation section (21) and negative voltage generation section (23) so as to provide voltage V.sub.2. If the voltage was simply changed from V.sub.1 to V.sub.2, the voltage would decrease slowly and require considerable time for the change. The positive/negative switching of the polarity induces the discharging of the electric charges accumulated at the output terminals, and consequently, the voltage-switching operation from V.sub.1 to V.sub.2 is quickly performed.

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.

A focusing ion guiding apparatus includes at least one ion guiding inlet and ion guiding outlet connected to each other via a transport axial line; at least one group of focusing electrode structures comprising at least one smooth and non-concave focusing electrode or focusing electrode array to which a focusing voltage is applied, the focusing electrode structure causing the ions transported in the apparatus to be radially focused for many times under the action of a focusing electric field formed by the focusing electrode structure; and a neutral gas flow transported in the axial direction, a diffusion path of the gas flow in an at least partially radial direction relative to the axial direction being blocked by the focusing electrode or its bearing substrate to increase a transport velocity of the gas flow in the axial direction and reduce retention or turbulence of the transported ions.

A first multipole assembly includes a first plurality of rod electrodes arranged about an axis and configured to confine ions radially about the axis. A second multipole assembly disposed adjacent to the first multipole assembly includes a second plurality of rod electrodes arranged about the axis and configured to confine the ions radially about the axis. An orientation of the first multipole assembly about the axis is rotationally offset relative to an orientation of the second multipole assembly about the axis.

An ion guide includes electrodes elongated along an axis from an entrance end to an exit end and spaced around the axis to surround an interior. The electrodes have polygonal shapes with inside surfaces disposed at a radius from the axis and having an electrode width tangential to a circle inscribed by the electrodes. An aspect ratio of the electrode width to the radius varies along the axis. The electrodes are configured to generate a two-dimensional RF electrical field in the interior having a multipole composition comprising one or more lower-order multipole components and one or more higher-order multipole components and varying along the axis in accordance with the varying aspect ratio, and having an RF voltage amplitude that varies along the axis.

A mass spectrometer includes a first vacuum chamber, which is provided with an atmospheric pressure interface communicating with an external atmospheric pressure environment and to a first vacuum pump, the range of working pressure P1 of the first vacuum chamber being P1>30 mbar; a second vacuum chamber, which is connected to the first vacuum chamber by means of a vacuum interface to receive the analyte from the first vacuum chamber and to a second vacuum pump, the range of working pressure P2 of the second vacuum chamber being 0.5 mbar≤P2≤30 mbar; and a third vacuum chamber, which is connected to the second vacuum chamber by means of a vacuum interface to receive the analyte from the second vacuum chamber and to a third vacuum pump, the first vacuum pump or the second vacuum pump being used as a forepump of the third vacuum pump.

A method of manufacturing a multipole device includes the steps of: (a) forming an intermediate device by assembling a plurality of components including a plurality of precursor multipole electrodes, wherein the plurality of precursor multipole electrodes in the assembled device extend along and are distributed around a central axis; (b) forming a multipole device from the intermediate device by machining the precursor multipole electrodes within the intermediate device to provide a plurality of multipole electrodes having a predetermined spatial relationship; wherein a first component of the multipole device that includes a multipole electrode is attached non-permanently to a second component of the multipole device, the first component including a first alignment formation, and the second component including a second alignment portion configured to engage with the first alignment formation on the first component so as to facilitate alignment of the first component and the second component when the first component and the second component are attached, thereby allowing the first component to be detached from and then reattached to the second component while retaining the predetermined spatial relationship between the plurality of multipole electrodes.

A single type quadrupole mass spectrometer equipped with an ion source by the ESI method, which is a small device including a vacuum pump having a relatively small evacuation speed. The internal diameter of a desolvation tube for introducing ions from an ionization chamber into a first intermediate vacuum chamber is set to 0.4 mm φ, which is large for a small mass spectrometer. The evacuation speed of a rotary pump is determined so that the product of the cross-sectional opening area of the desolvation tube and the pressure in the first intermediate vacuum chamber falls within a range of 15 to 40 mm.sup.2.Math.Pa. This can ensure high detection sensitivity and reduce clogging of the desolvation tube due to droplets. Since the pressure in the first intermediate vacuum chamber does not need to be increased more than necessary, a small rotary pump having a small evacuation speed can be used.

To acquire a mass spectrum for a wide mass range, a normal analysis execution controlling unit controls components to repeatedly perform measurement while changing setting m/z by a predetermined m/z at a time, and a mass spectrum summarizing processing unit summarizes data pieces each obtained by each time of measurement to generate the mass spectrum. Radio-frequency voltage applied to an ion guide and the like is changed based on the setting m/z. The radio-frequency voltage for the setting m/z is determined using a table in which a relationship between a position on an axis between upper and lower limits of the mass range and the radio-frequency voltage is substantially the same regardless of the mass range.