Ion Beam Mass Pre-Separator

A mass spectrometer system, comprising:

• a continuous flux ion source for producing a beam of ions comprising ions having a first range of mass-to-charge (m/z) ratios;
• an ion flux separator disposed in fluid communication with the ion source and comprising:
• an electrode arrangement having a length extending in an axial direction between a first end thereof and a second end thereof, the second end opposite the first end, and the first end configured to introduce the beam of ions from the continuous flux ion source into an ion transmission space of the electrode arrangement;
• wherein the electrode arrangement comprises a single quadrupole electrode assembly comprising a substantially parallel arrangement of four non-segmented, rod-shaped electrodes;
• and,
• wherein the electronic controller is configured to apply the RF potential to at least some of the non-segmented rod-shaped electrodes;
• and,
• an electronic controller in electrical communication with the electrode arrangement and configured to apply an RF potential and a DC potential to at least an electrode of the electrode arrangement forming a plurality of separate ion beamlets, each ion beamlet having m/z ratios within a different second range of m/z ratios, and each second range of m/z ratios being within the first range of m/z ratios;
• at least one mass analyzer in fluid communication with the ion flux separator for receiving separately each one of the separate ion beamlets;
• and,
• wherein the beam of ions is split into a plurality of spatially separate ion beamlets of narrower m/z ratio ranges than the first range of m/z ratios, stored in separate independently controlled ion storage cells, released from each storage cell when a predetermined amount of ions have accumulated in the storage cells and analyzed in at least one mass analyzer.

A method of mass spectrometry, comprising:

• using a continuous flux ion source, producing a beam of ions having mass-to-charge (m/z) ratios within a predetermined first range of m/z ratios;
• introducing the beam of ions into an ion flux separator that is disposed between the ion source and at least one mass analyzer, the ion flux separator having a length extending in an axial direction, wherein the ion flux separator comprises a single quadrupole electrode assembly comprising a substantially parallel arrangement of four non-segmented, rod-shaped electrodes;
• applying an RF potential and a DC potential to at least an electrode of the ion flux separator, thereby establishing a ponderomotive RF electric field and a mass-independent DC electric field, the RF potential and the DC potential applied such that a ratio of the strength of the ponderomotive RF electric field to the strength of the mass-independent DC electric field in a transverse dimension orthogonal to the axial direction varies along the length of the ion flux separator, wherein applying the DC potential comprises providing at least one DC-biased extraction electrode arranged adjacent to one side of the quadrupole electrode assembly;
• extracting ions having different m/z ratios at different respective locations along the length of the ion flux separator, the extracted ions forming a plurality of separate ion beamlets, each ion beamlet consisting essentially of ions having m/z ratios within a different second range of m/z ratios, and each second range of m/z ratios being within the first range of m/z ratios;
• and,
• using the at least one mass analyzer, receiving separately each of the plurality of separate ion beams for performing in aggregate an analysis of the introduced ion beam, wherein the beam of ions is split into a plurality of spatially separate ion beamlets of narrower m/z ratio ranges than the first range of m/z ratios, stored in separate independently controlled ion storage cells, released from each storage cell when a predetermined amount of ions have accumulated in the storage cells and analyzed in at least one mass analyzer.