Targeted analysis for tandem mass spectrometry

摘要

A tandem mass spectrometer and method are described. Precursor ions are generated in an ion source and an ion injector injects ions towards a downstream ion guide via a single or multi reflection TOF device that separates ions into packets in accordance with their m/z. A single pass ion page in the path of the precursor ions between the ion injector and the ion guide is controlled so that (only a subset of precursor ion packets, containing precursor ions of interest, is allowed onward transmission to the ion guide. A high resolution mass spectrometer is provided for analysis of those ions, or their fragments, which have been allowed passage through the ion gate. The technique permits multiple m/z ranges to be selected from a wise mass range of precursors, with optional fragmentation of one or more of the chosen ion species.

主权项

1. A method of analyzing substances by mass spectrometry, comprising the steps of:
(a) generating precursor ions in an ion source; (b) guiding the precursor ions along an input axis into an ion accelerator; (c) ejecting the precursor ions from the ion accelerator along an output axis towards a time-of-flight (TOF) mass analyser, wherein the output axis is substantially orthogonal with respect to the input axis; (d) separating the precursor ions according to their mass-to-charge ratios (m/z's) in the TOF mass analyser, such that the precursor ions arrive at an ion gate located downstream of the TOF mass analyser as a temporally separated plurality of ion packets, each ion packet containing ions of a respective one of a plurality of different ion species; (e) controlling the ion gate so as to sequentially select from the plurality of ion packets arriving at the ion gate, a subset of a plurality of ion packets deriving from a subset of precursor ion species of interest; (f) mixing the selected subset of the plurality of ion packets; and (g) analyzing the resulting ion population derived from the mixed selected subset of ion packets in a high resolution mass analyzer.