Multi-pole ion trap for mass spectrometry

摘要

An ion trap includes a containment region for containing ions, and a plurality of electrodes positioned on a regular polyhedral structure encompassing the containment region. An electrode is positioned on each vertex of the encompassing structure and at least one of the polygonal surfaces includes additional electrodes configured to form a plurality of quadrupoles on the surface. Alternating RF voltage is applied to the plurality of electrodes, so that directly neighboring electrodes are of equal amplitude and opposite polarity at any point in time. This configuration on the polyhedral structure forms a potential barrier for repelling the ions from each of the regular polygonal surfaces and containing them in the trap. Mass selective filters can be formed from the quadrupoles for parallel mass analysis in different m/z windows. Application of a small DC potential to a plate electrode outside the quadrupoles preferentially depletes single charged ions for enhanced signal-to-noise analysis.

主权项

1. A method for storing ions comprising:
providing a plurality of electrodes arranged in a polyhedral structure, said polyhedral structure including a plurality of regular polygonal surfaces defining a containment region within said structure; injecting ions into said containment region of said polyhedral structure; applying RF voltage to said plurality of electrodes such that neighboring electrodes are maintained at any point in time at opposing polarities, whereby a plurality of quadrupoles are formed from said plurality of electrodes for repelling the ions from each of said regular polygonal surfaces for containing the ions within said containment region; and applying RF voltage to a quadrupole ion guide provided adjacent said polyhedral structure for guiding ions out of said containment region, wherein ions are ejected from said containment region in a mass-to-charge dependent matter, and wherein a plurality of quadrupole ion guides are provided and RF voltages of different characteristic frequencies corresponding to different mass-to-charge windows are applied to said plurality of quadrupole ion guides for parallel analysis of mass-to-charge values of a range of ions stored in said containment region.