NOVEL LINEAR ION TRAP FOR MASS SPECTROMETRY

摘要

A method for manipulating ions in an ion trap includes storing ions, spatially compressing, and ejecting selected ions according to mass-to-charge ratio. An ion trap includes an injection port, an arm having a first and a second end for confining and spatially compressing the ions, and an ejection port for ejecting the ions from the second end. The arm includes two pairs of opposing electrodes, which provide a quadrupole electric field potential at any cross- section of the ion trap. The distance between opposing electrodes and the cross-sectional area of the electrodes increases from the first to second end. The electrodes may be tapered cylindrical rods or of hyperbolic cross-section. Ions selected for ejection are spatially compressed into a region at the second (wider) end. The ion trap may include one arm, with either orthogonal or axial ejection, or two arms with a central insert for orthogonal ejection.