US 2020/0051800 A1 · METHODS AND APPARATUS FOR IMPROVED TANDEM MASS SPECTROMETRY DUTY CYCLE

Abstract

A method for parallel accumulation and serial fragmentation of ions, wherein ions are injected into a device capable of serial ejection using a pseudopotential barrier created by an RF voltage. In all instances, the ions may be filtered prior to accumulation in the device capable of serial ejection. In some cases this filtering may take the form of discrete isolation windows using isolation waveforms with multiple notches. In some cases these waveforms may be applied to a quadrupole mass filter. Following accumulation of the precursor ions, the initial population may be serially ejected using a pseudopotential barrier created by an RF voltage. Following serial ejection, the individual precursor ion populations are analyzed. In some cases, this analysis might involve additional rounds of ion isolation and manipulation (e.g., MSn, CID, ETD, etc.).

Claims24

Dependent claims

A method for mass spectrometric analysis of ions of a plurality of ion species generated by ionization of a sample, comprising:

(a) isolating a plurality of portions of the ions, each portion consisting of a subset of the ion species within a respective range of mass-to-charge (m/z) values;
(b) simultaneously retaining the isolated plurality of portions of the ions in an ion storage apparatus, wherein the retaining is at least partially facilitated by applying an auxiliary radio-frequency (RF) voltage waveform to a one of two electrode members of the ion storage apparatus, thereby generating a pseudopotential between the two electrode members, each electrode member either consisting of a single electrode or comprising a group of electrodes;
(c) releasing the retained isolated portions of the ion species one at a time from the ion storage apparatus, the releasing comprising one or more of:
varying a DC potential applied to a one of the electrode members, varying DC potentials applied to both of the electrode members, or reducing an amplitude of the applied auxiliary RF voltage waveform;
and
(d) fragmenting or reacting each released portion of the ion species to thereby generate a respective set of product ion species and mass analyzing the product ion species.

3 more elements

A mass spectrometer system comprising:

(i) an ionization source;
(ii) a mass filter apparatus configured to receive ions from the ionization source;
(iii) a fragmentation or reaction cell configured to receive ions filtered according to mass-to-charge ratio (m/z) by the mass filter and to trap and/or fragment or react the received ions so as to thereby generate product ions;
(iv) a mass analyzer configured to receive, mass analyze and detect the product ions;
(v) an ion guide having an axis, the ion guide comprising:
(a) an entrance lens configured to receive the filtered ions from the mass filter;
(b) an exit lens disposed downstream from the entrance lens and configured to transmit the filtered ions to the fragmentation or reaction cell;
and
(c) a plurality of electrodes disposed between the entrance and exit lenses;
and
(vi) one or more power supplies electrically coupled to the ion guide, the fragmentation or reaction cell and the mass analyzer, the one or more power supplies are configured to:
supply an oscillatory radio-frequency (RF) voltage to the plurality of electrodes that confines ions within the ion guide to a vicinity of the axis;
supply an auxiliary radio-frequency (RF) voltage waveform either to the exit lens or, with phase synchronicity, to all of the electrodes disposed between the entrance and exit lenses;
and
supply a variable DC potential difference between the plurality of electrodes and the exit lens.

12 more elements

A mass spectrometer system comprising:

(i) an ionization source;
(ii) a mass filter apparatus configured to receive ions from the ionization source;
(iii) a fragmentation or reaction cell configured to receive ions filtered according to mass-to-charge ratio (m/z) by the mass filter and to trap and/or fragment or react the received ions so as to thereby generate product ions;
(iv) a mass analyzer configured to receive, mass analyze and detect the product ions;
(v) an ion guide configured to receive the filtered ions from the mass filter and to transmit the filtered ions to the fragmentation or reaction cell, the ion guide comprising:
an entrance end and an ion exit end;
an axis extending between the ion entrance and exit ends;
and
a sequence of sections disposed along the axis from the entrance lens to the exit lens, each section comprising:
a stack of two or more plate electrodes, each plate electrode comprising an aperture, the plurality of apertures of all plate electrodes defining an ion channel through the ion guide;
(vi) one or more power supplies electrically coupled to the ion guide, the fragmentation or reaction cell and the mass analyzer, wherein the one or more power supplies are configured to:
supply a radio-frequency (RF) confining voltage to the stack of plate electrodes, a phase difference of the RF confining voltage being 180 degrees between each pair of adjacent plate electrodes;
supply an auxiliary RF voltage waveform to all plate electrodes of a section, each of a phase, amplitude and frequency of the provided auxiliary RF voltage being identical among all electrodes of the section;
and
supply a DC potential difference between the section to which the auxiliary RF voltage is provided and a second section that is adjacent thereto.

12 more elements

A mass spectrometer system comprising:

(i) an ionization source;
(ii) a mass filter apparatus configured to receive ions from the ionization source;
(iii) a fragmentation or reaction cell configured to receive ions filtered according to mass-to-charge ratio (m/z) by the mass filter and to trap and/or fragment or react the received ions so as to thereby generate product ions;
(iv) a mass analyzer configured to receive, mass analyze and detect the product ions;
(v) an ion guide configured to receive the filtered ions from the mass filter and to transmit the filtered ions to the fragmentation or reaction cell, the ion guide comprising:
an entrance end and an ion exit end;
an axis extending between the ion entrance and exit ends;
and
a sequence of sections disposed along the axis from the entrance lens to the exit lens, each section comprising:
a respective plurality of rod electrode segments, each rod electrode segment disposed about and parallel to the axis;
(vi) one or more power supplies electrically coupled to the ion guide, the fragmentation or reaction cell and the mass analyzer, wherein the one or more power supplies are configured to:
supply a radio-frequency (RF) confining voltage to the rod electrode segments;
supply an auxiliary RF voltage waveform to all rod electrode segments of a section, wherein a phase, amplitude and frequency of the provided auxiliary RF voltage is identical among all rod electrode segments of the section;
and
supply a DC potential difference between the section to which the auxiliary RF voltage is provided and a second section that is adjacent thereto.

12 more elements

Dependencies are inferred from the claim text.

Methods and apparatus for improved tandem mass spectrometry duty cycle

Life of this patent

Methods and apparatus for improved tandem mass spectrometry duty cycle

Life of this patent

Abstract

Claims24