Method to perform beam-type collision-activated dissociation in the pre-existing ion injection pathway of a mass spectrometer

摘要

Described herein are methods and systems related to the use of the pre-existing ion injection pathway of a mass spectrometer to perform beam-type collision-activated dissociation, as well as other dissociation methods. The methods can be practiced using a wide range of mass spectrometer configurations and allows MSn experiments to be performed on very basic mass spectrometers, even those without secondary mass analyzers and/or collision cells. Following injection and selection of a particular ion type or population, that population can be fragmented via beam-type collision-activated dissociation (CAD), as well as other dissociation methods, using the pre-existing ion injection pathway or inlet of a mass spectrometer. For CAD applications, this is achieved by transmitting the ions back along the ion injection pathway with a high degree of kinetic energy. As the ions pass into the higher pressure regions located in or near the atmospheric pressure inlet, the ions are fragmented and then trapped. Following fragmentation and trapping, the ions can either be re-injected into the primary ion selection device or sent on to a secondary mass analyzer.

主权项

1. A mass spectrometer device for analyzing a sample, the device comprising:
a separation stage for fractionating said sample, thereby generating a fractionated sample; an ion source operably connected to said separation stage for generating ions from the fractionated sample; one or more chambers having an inlet for receiving the ions and having ion injection pathway ion optics for transmitting the ions along an ion injection pathway between the inlet and an ion selection device; the ion selection device having ion selection device ion optics, the ion selection device in fluid communication with the one or more chambers for receiving the ions and selecting a subset of the ions having a preselected range of mass-to-charge ratios; and a controller operably connected to the ion optics of the one or more chambers; wherein the controller controls the ion optics so as:
to transmit the ions along a first direction away from the inlet through the ion injection pathway into the ion selection device; andto transmit the subset of the ions having the preselected range of mass-to-charge ratios along a second direction toward the inlet through the ion injection pathway; wherein the ion injection pathway ion optics have an RF voltage component and a DC voltage component which are under independent control with respect to the ion selection device ion optics; wherein the ion injection pathway ion optics comprise two or more multipole RF devices and one or more ion lens devices, wherein the multipole RF devices and the ion lens devices are provided between the inlet and the ion selection device and wherein at least one ion lens device is provided between adjacent multipole RF devices; wherein the subset of the ions transmitted along the second direction interact with one or more gases at a pressure greater than 0.01 Torr in the inlet or ion injection pathway and undergo dissociation, thereby fragmenting at least a portion of the subset of the ions having the preselected range of mass-to-charge ratios to generate product ions.