Patent ID: 7064317
Filing Date: 2006-06-20
Classification: H01J

Abstract:
1. A method of operating an ion trap, comprising: (a) creating an ion trapping potential within a chamber of said ion trap with an electrode assembly of said ion trap; (b) disposing a population of ions in an area defined by said ion trapping potential, wherein (i) said population of ions includes a first subpopulation of ions and a second subpopulation of ions, (ii) each ion of said first subpopulation of ions carries multiple charges, (iii) each ion of said first subpopulation of ions has a mass-to-charge ratio which is the same or different as other ions of said first subpopulation of ions such that ions of said first subpopulation of ions define a range of mass-to-charge ratios, and (iv) each ion of said second subpopulation of ions carries a charge which is opposite to a charge carried by each ion of said first subpopulation of ions; and (c) exposing said population of ions to a first resonance excitation frequency during a mass-to-charge altering reaction between said first subpopulation of ions and said second subpopulation of ions, said first resonance excitation frequency being tuned so that (i) when an ion of said first subpopulation of ions attains a first predetermined mass-to-charge ratio, said ion having said first predetermined mass-to-charge ratio is selectively inhibited from reacting with ions of said second subpopulation of ions and (ii) ions of said first subpopulation of ions having said first predetermined mass-to-charge ratio are selectively accumulated in said chamber of said ion trap during said exposure of said population of ions to said first resonance excitation frequency.