US 7,459,679 B2 · Method and apparatus for mass selective axial transport using pulsed axial field

Abstract

A mass spectrometer system has an elongated rod set having an entrance end, an exit end, a plurality of rods and a central longitudinal axis. The mass spectrometer system is operable to perform the following steps: a) admitting a first plurality of groups of ions into the entrance end of the rod set; b) producing a field between the plurality of rods to confine the first plurality of groups of ions in the rod set; c) selecting a first mass/charge range for a first group of ions in the first plurality of groups of ions; d) providing a first radial excitement field to radially displace the first group of ions within the first mass/charge range from the central longitudinal axis, and concurrently retaining a second group of ions closer to the central longitudinal axis than the first group of ions, the second group of ions being within a second mass/charge range disjoint from the first mass/charge range; and then e) providing a first axial force acting on the first group of ions by providing an axial acceleration field. The first axial force is not provided during step d).

Claims22

Dependent claims

A method of operating a mass spectrometer system having an elongated rod set, the rod set having an entrance end, an exit end, a plurality of rods and a central longitudinal axis, the method comprising:

a) admitting a first plurality of groups of ions into the entrance end of the rod set;
b) producing a field between the plurality of rods to confine the first plurality of groups of ions in the rod set;
c) selecting a first mass/charge range for a first group of ions in the first plurality of groups of ions;
d) providing a first radial excitement field to radially displace the first group of ions within the first mass/charge range from the central longitudinal axis, and concurrently retaining a second group of ions closer to the central longitudinal axis than the first group of ions, the second group of ions being within a second mass/charge range disjoint from the first mass/charge range;
and then
e) providing a first axial force acting on the first group of ions by providing an axial acceleration field;
wherein the first axial force is not provided during step d).

4 more elements

A mass spectrometer system comprising:

a) an ion source;
b) a rod set, the rod set having a plurality of rods extending along a longitudinal axis, an entrance end for admitting ions from the ion source, and an exit end for ejecting ions traversing the longitudinal axis of the rod set;
c) a voltage supply module for producing an RF field between the plurality of rods of the rod set;
and,
d) a controller for controlling the voltage supply module to provide a radial excitement field to, i) during an excitation phase of operation, radially displace a first group of ions within a selected mass/charge range from the central longitudinal axis, and concurrently retain a second group of ions closer to the central longitudinal axis than the first group of ions, the second group of ions being within a second mass/charge range disjoint from the selected mass/charge range;
and then ii) during an axial acceleration phase of operation, provided an axial force acting on the first group of ions by providing an axial acceleration field;
wherein the controller is further operable to control the voltage supply module to interrupt the axial acceleration field during the excitation phase of operation such that the derived axial force is not provided during the excitation phase of operation.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for mass selective axial transport using pulsed axial field

Life of this patent

Method and apparatus for mass selective axial transport using pulsed axial field

Life of this patent

Abstract

Claims22