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.