Abstract: An electrospray ion source for a mass spectrometer for generating ions of an analyte from a sample comprising the analyte dissolved in a liquid solvent comprises: an electrode receiving the sample and comprising at least a first plurality of protrusions protruding from a base, each protrusion of the at least a first plurality of protrusions having a respective tip; and a voltage source, wherein, in operation of the electrospray ion source, the sample is caused to move, in the presence of a gas or air, from the base to each protrusion tip along a respective protrusion exterior so as to form a respective stream of charged particles emitted towards an ion inlet aperture of the mass spectrometer under application of voltage applied to the electrode from the voltage source.

Abstract: An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U? (r, ?, z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U?(r, ?, z) is the result of a perturbation W to an ideal field U(r, ?, z) which, for example, is hypologarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, ?, z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than 2 n radians over an ion detection period Tm.

Abstract: This invention relates to mass spectrometry that includes ion trapping in at least one of the stages of mass analysis. In particular, although not exclusively, this invention relates to tandem mass spectrometry where precursor ions and fragment ions are analysed. A method of mass spectrometry is provided comprising the sequential steps of: accumulating in an ion store a sample of one type of ions to be analysed; accumulating in the ion store a sample of another type of ions to be analysed; and mass analysing the combined samples of the ions; wherein the method comprises accumulating the sample of the one type of ions and/or the sample of another type of ions to achieve a target number of ions based on the results of a previous measurement of the respective type of ions.

Abstract: Methods and analyzers useful for time of flight mass spectrometry are provided.

Abstract: The present invention provides a method of reflecting ions in a multireflection time of flight mass spectrometer comprising providing an ion mirror having a plurality of electrodes, the ion mirror having a cross section with a first, minor axis (Y) and a second, major axis (X) each perpendicular to a longitudinal axis (Z) of the ion mirror which lies generally in the direction of time of flight separation of the ions in the mirror; guiding ions towards the ion mirror; applying a voltage to the electrodes so as to create an electric field which: (a) causes the mean trajectory of the ions to intersect a plane of symmetry of the ion mirror which contains the longitudinal (Z) and major axes (X) of the mirror; (b) causes the ions to reflect in the ion mirror; and (c) causes the ions to exit the ion mirror in a direction such that the mean trajectory of ions passing through the ion mirror has a component of movement in a direction (Y) perpendicular to and diverging from the said plane of symmetry thereof.

Abstract: A method of operating a gas-filled collision cell in a mass spectrometer is provided. The collision cell has a longitudinal axis. Ions are caused to enter the collision cell. A trapping field is generated within the collision cell so as to trap the ions within a trapping volume of the collision cell, the trapping volume being defined by the trapping field and extending along the longitudinal axis. Trapped ions are processed in the collision cell and a DC potential gradient is provided, using an electrode arrangement, resulting in a non-zero electric field at all points along the axial length of the trapping volume so as to cause processed ions to exit the collision cell. The electric field along the axial length of the trapping volume has a standard deviation that is no greater than its mean value.

Abstract: An ion transfer tube for a mass spectrometer comprises a tube member having an inlet end and an outlet end; and at least one bore extending through the tube member from the inlet end to the outlet end, the at least one bore having a non-circular cross section. A method of forming an ion transfer tube comprises the steps of providing a tube member having a length and an internal bore, the internal bore having a wall of circular cross section; and etching or eroding portions of the tube member adjacent to the wall so as to form an enlarged bore having a non-circular cross section.

Abstract: This invention relates to a method of trapping ions and to an ion trapping assembly. In particular, the present invention has application in gas-assisted trapping of ions in an ion trap prior to a mass analysis of the ions in a mass spectrometer. The invention provides a method of trapping ions in a target ion trap of an ion trapping assembly that comprises a series of volumes arranged such that ions can traverse from one volume to the next, the volumes including the target ion trap, whereby ions are allowed to pass repeatedly through the volumes such that they also pass into and out from the target ion trap without being trapped. Potentials may be used to reflect the ions from respective ends of the ion trapping assembly. Optionally, a potential well and/or gas-assisted cooling may be used to cause the ions to settle in the target ion trap.

Abstract: An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U?(r, ?, z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U?(r, ?, z) is the result of a perturbation W to an ideal field U(r, ?, z) which, for example, is hyperlogarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, ?, z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than 2 ? radians over an ion detection period Tm.

Abstract: A method of operating a gas-filled collision cell in a mass spectrometer is provided. The collision cell has a longitudinal axis. Ions are caused to enter the collision cell. A trapping field is generated within the collision cell so as to trap the ions within a trapping volume of the collision cell, the trapping volume being defined by the trapping field and extending along the longitudinal axis. Trapped ions are processed in the collision cell and a DC potential gradient is provided, using an electrode arrangement, resulting in a non-zero electric field at all points along the axial length of the trapping volume so as to cause processed ions to exit the collision cell. The electric field along the axial length of the trapping volume has a standard deviation that is no greater than its mean value.

Abstract: An electrospray ion source for a mass spectrometer for generating ions of an analyte from a sample comprising the analyte dissolved in a liquid solvent comprises: an electrode receiving the sample and comprising at least a first plurality of protrusions protruding from a base, each protrusion of the at least a first plurality of protrusions having a respective tip; and a voltage source, wherein, in operation of the electrospray ion source, the sample is caused to move, in the presence of a gas or air, from the base to each protrusion tip along a respective protrusion exterior so as to form a respective stream of charged particles emitted towards an ion inlet aperture of the mass spectrometer under application of voltage applied to the electrode from the voltage source.

Abstract: An ion transfer arrangement for transporting ions between higher and lower pressure regions of the mass spectrometer comprises an ion transfer conduit 60. The conduit 60 has an inlet opening towards a relatively high pressure chamber 40 and an outlet 70 opening towards a relatively low pressure chamber. The conduit 60 also has at least one side wall surrounding an ion transfer channel 115. The side wall includes a plurality of apertures 140 formed in the longitudinal direction of the side wall so as to permit a flow of gas from within the ion transfer channel 115 to a lower pressure region outside of the side wall of the conduit 60.

Abstract: An electrospray ion source for a mass spectrometer includes an electrode comprising at least a first plurality of protrusions protruding from a base, each protrusion of the at least a first plurality of protrusions having a respective tip; a conduit for delivering an analyte-bearing liquid to the electrode; and a voltage source, wherein, in operation of the electrospray ion source, the analyte-bearing liquid is caused to move, in the presence of a gas or air, from the base to each protrusion tip along a respective protrusion exterior so as to form a respective stream of charged particles emitted towards an ion inlet aperture of the mass spectrometer under application of voltage applied to the electrode from the voltage source.

Abstract: An ion transfer tube for a mass spectrometer comprises a core member and a first jacket tube member at least partially enclosing the core member and providing one or more channels therethrough. A method of forming an ion transfer tube, comprises: providing a first jacket tube member having a length and an internal bore, the internal bore passing along the length and defining an interior surface of circular cross section; removing at least one portion of the first jacket tube member adjacent to the interior surface so as to form at least one groove, channel, slot, recess or embayment of or in the interior surface; and providing a core member within the bore of the jacket tube member such that remnant portions of the interior surface of circular cross section mate against portions of an exterior surface of the core member.

Abstract: There is provided of an on mobility spectrometer for separating ions according to their on mobility comprising, in various aspects: a drift tube having therein a drift space and in the drift space at least two on separation paths of different lengths: a straight drift tube having therein a helical ion separation path; a helical on separation path surrounding an axially extending inner electrode assembly; and a drift tube for separating ions according to their ion mobility wherein a rotating arcuate electric field is applied in operation to separate ions having an ion mobility such that their rotational velocity in the drift tube is matched to the rotational velocity of the rotating arcuate electric field. Various methods for separating ions according to their on mobility are also provided.

Abstract: An electrostatic trap such as an orbitrap is disclosed, with an electrode structure. An electrostatic trapping field of the form U?(r, ?, z) is generated to trap ions within the trap so that they undergo isochronous oscillations. The trapping field U?(r, ?, z) is the result of a perturbation W to an ideal field U(r, ?, z) which, for example, is hyperlogarithmic in the case of an orbitrap. The perturbation W may be introduced in various ways, such as by distorting the geometry of the trap so that it no longer follows an equipotential of the ideal field U(r, ?, z), or by adding a distortion field (either electric or magnetic). The magnitude of the perturbation is such that at least some of the trapped ions have an absolute phase spread of more than zero but less than 2 ? radians over an ion detection period Tm.

Abstract: Methods and analysers useful for time of flight mass spectrometry are provided.

Abstract: A method of separating charged particles using an analyser is provided, the method comprising: causing a beam of charged particles to fly through the analyser and undergo within the analyser at least one full oscillation in the direction of an analyser axis (z) of the analyser whilst orbiting about the axis (z) along a main flight path; constraining the arcuate divergence of the beam as it flies through the analyser; and separating the charged particles according to their flight time. An analyser for performing the method is also provided. At least one arcuate focusing lens is preferably used to constrain the divergence, which may comprise a pair of opposed electrodes located either side of the beam.

Abstract: A method of transporting gas and entrained ions between higher and lower pressure regions of a mass spectrometer comprises providing an ion transfer conduit 60 between the higher and lower pressure regions. The ion transfer conduit 60 includes an electrode assembly 300 which defines an ion transfer channel. The electrode assembly 300 has a first set of ring electrodes 305 of a first width D1, and a second set of ring electrodes of a second width D2 (?D1) and interleaved with the first ring electrodes 305. A DC voltage of magnitude V1 and a first polarity is supplied to the first ring electrodes 205 and a DC voltage of magnitude V2 which may be less than or equal to the magnitude of V1 but with an opposed polarity is applied to the second ring electrodes 310. The pressure of the ion transfer conduit 60 is controlled so as to maintain viscous flow of gas and ions within the ion transfer channel.

Abstract: An ion transfer arrangement for transporting ions between higher and lower pressure regions of the mass spectrometer comprises an ion transfer conduit 60. The conduit 60 has an inlet opening towards a relatively high pressure chamber 40 and an outlet 70 opening towards a relatively low pressure chamber. The conduit 60 also has at least one side wall surrounding an ion transfer channel 115. The side wall includes a plurality of apertures 140 formed in the longitudinal direction of the side wall so as to permit a flow of gas from within the ion transfer channel 115 to a lower pressure region outside of the side wall of the conduit 60.