Device for ion sorting by m/z

A system for sorting ions by mass-to-charge ratio (m/z) values, comprising:

• a first array of N evenly spaced, parallel, and coplanar electrodes;
• a second array of N evenly spaced, parallel, and coplanar electrodes aligned with the first array so that there is a uniform gap between the first array and the second array and so that each electrode of the first array is aligned with a corresponding electrode of the second array in a plane that is perpendicular to the plane of the first array,
• a radio frequency (RF) voltage source and circuit that applies an RF voltage across each electrode of the first array and its corresponding electrode of the second array that varies in amplitude with each succeeding electrode of the first array according to an RF voltage amplitude gradient and changes phase by 180 degrees with each succeeding electrode of the first array in order to produce an array of N−1 different quadrupole RF electric fields in the uniform gap;
• a direct current (DC) voltage source and circuit that superimpose a DC voltage on each electrode of the first array and its corresponding electrode of the second array that varies in voltage with each succeeding electrode of the first array according to a DC voltage gradient in order to produce a DC electric field in the uniform gap so that, when ions of an ion beam of a mass spectrometer are introduced in the uniform gap near a quadrupole RF electric field with a lower RF voltage amplitude, the DC electric field causes the ions to drift toward quadrupole RF electric fields with increasing RF voltage amplitudes where the ions are trapped according to their m/z values;
• an enclosure that encloses the first array and the second array, receives the beam of ions through an ion inlet, receives a cooling gas through a gas inlet, and confines the cooling gas under vacuum so that cooling gas cools the ions in the uniform gap sufficiently to prevent the ions from being trapped in a quadrupole RF electric fields that do not correspond to the m/z values of the ions,
• wherein the enclosure further includes an inlet wall electrode that includes the ion inlet and the inlet wall electrode is DC biased with respect to the electrodes of the first array and the electrodes of the second array so that the ions are drawn into the enclosure through the ion inlet,
• wherein the enclosure further includes an outlet wall electrode that includes an ion outlet positioned proximate to a quadrupole RF electric field of the N−1 different quadrupole RF electric fields in the uniform gap that has the highest RF voltage amplitude and the outlet wall electrode is DC biased with respect to the electrodes of the first array and the electrodes of the second array so that ions trapped in the quadrupole RF electric field of the N−1 different quadrupole RF electric fields in the uniform gap that has the highest RF voltage amplitude are ejected from the enclosure through the ion outlet,
• wherein the RF voltage source is sequentially stepped to lower RF voltage amplitudes to shift ions trapped in the N−1 different quadrupole RF electric fields to adjacent quadrupole RF electric fields and sequentially eject all trapped ions out through the ion outlet.

A method for sorting ions by mass-to-charge ratio (m/z) values, comprising:

• applying an radio frequency (RF) voltage across each electrode of a first array of N evenly spaced, parallel, and coplanar electrodes and its corresponding electrode of a second array of N evenly spaced, parallel, and coplanar electrodes that varies in amplitude with each succeeding electrode of the first array according to an RF voltage amplitude gradient and changes phase by 180 degrees with each succeeding electrode of the first array in order to produce an array of N−1 different quadrupole RF electric fields in a uniform gap between the first array and the second array,
• wherein the first array and the second array are aligned so that each electrode of the first array is aligned with a corresponding electrode of the second array in a plane that is perpendicular to the plane of the first array;
• and
• superimposing a direct current (DC) voltage on each electrode of the first array and its corresponding electrode of the second array that varies in voltage with each succeeding electrode of the first array according to a DC voltage gradient in order to produce a DC electric field in the uniform gap so that, when ions of an ion beam of a mass spectrometer are introduced in the uniform gap near a quadrupole RF electric field with a lower RF voltage amplitude, the DC electric field causes the ions to drift toward quadrupole RF electric fields with increasing RF voltage amplitudes where the ions are trapped according to their m/z values,
• wherein the N electrodes of the first array are N metal layers of a first printed circuit board (PCB) and the N electrodes of the second array are N metal layers of a second PCB, and
• wherein the first PCB further includes N−1 metal layers between the N metal layers and the second PCB includes N−1 metal layers between the N metal layers.