Thermo Finnigan LLC

University of Florida Research Foundation, Incorporated

Michael William Belford

Jean-Jacques Dunyach

Jean Jacques Dunyach

Satendra Prasad

Mark E Hardman

Michael W Senko

Jae C Schwartz

Viatcheslav V Kovtoun

Roger Guevremont

Philip M Remes

Richard Alan Yost

Randy W Purves

R Paul Atherton

Bennett S Kalafut

Berg A Tehlirian

Ragnar Dworschak

Dhruva D Kulkarni

Christopher Karl Hilton

Richard Yost

Adjusting compensation voltage (CV) parameters of an ion mobility device is described. In one instance, the CV parameters are adjusted to reflect a different CV range, a number of CV steps, or a CV step size to increase throughput of a mass spectrometer.

Compensation voltage adjustment for ion mobility separation

A FAIMS device interfaces between an ionization source and a mass spectrometer. The FAIMS device includes inner and outer electrodes having radially opposed surfaces, which define there between a gap through which ions are transported. A waveform generator is configured to apply a selected one of two distinct periodic waveforms to the electrodes, consisting of: a first waveform characterized by equal high and low amplitudes and periods and a second waveform including a bi-sinusoidal waveform superimposed with a DC compensation voltage. The device is configured to toggle between a transmission mode of operation in which ions are passed through the device with no spatial separation when the first waveform is applied to the inner and/or outer electrodes and a separation mode of operation in which spatial separation of the ions occurs in the gap when the bi-sinusoidal waveform and DC voltage are applied to the inner and/or outer electrodes.

FAIMS device for separation or transmission of ions

A method of operating a system comprising a chromatograph and a mass spectrometer comprises: (a) providing an abundance threshold and a list comprising respective entries for precursor ion species of interest comprising respective precursor-ion m/z ratios; (b) transmitting a first sample fraction portion comprising a plurality of sample-fraction ion species through an ion mobility spectrometer operated in non-dispersive mode to the mass spectrometer; (c) detecting a respective abundance at each of a plurality of sample-fraction m/z ratios; and (d) upon detection of an above-threshold ion abundance at an m/z-ratio corresponding to a first precursor ion species of interest: (d1) inletting a second sample fraction portion into the ion mobility spectrometer operated in dispersive mode such that ions of the first precursor-ion species are preferentially transmitted therethrough; (d2) fragmenting the preferentially-transmitted ions so as to generate product ion species; and (d3) detecting the product ion species.

System comprising a mass spectrometer coupled to a FAIMS apparatus and methods of operation

A method is described for identifying the occurrence and location of charging of ion optic devices arranged along the ion path of a mass spectrometer. The method includes repeatedly performing a sequence of introducing a beam of discharge ions to a location on the ion path, and subsequently measuring the intensities of opposite-polarity sample ions delivered to a mass analyzer, with the discharge ions being delivered to a location further downstream in the ion path at each successive sequence.

Identifying the occurrence and location of charging in the ion path of a mass spectrometer

A method for transmitting ions entrained in a flowing carrier gas into and through a gap defined by a pair of mutually facing curved electrodes comprises: inputting the ions and flowing gas into the gap through an ion inlet orifice of a first one of the pair of electrodes, the ion inlet orifice comprising an orifice wall, an orifice inlet end and an orifice outlet end, the orifice wall being smoothly convexly curved between the inlet end and the outlet end, wherein a width of the gap and a flow rate of the carrier gas through the ion inlet orifice and gap are such that the gas flow is laminar within the ion inlet orifice and gap.

Method for transmitting ions and carrier gas between mutually facing curved electrodes

A ion source for a mass spectrometer comprises: a capillary having a nozzle for emitting a nebulized fluid sample; an electrode of the capillary; a high voltage power supply; a second electrode disposed within or configurable to be disposed within a path of the nebulized fluid sample; and at least one switch for selecting application of an electrical potential provided by the high voltage power supply to either or both of the capillary electrode or the second electrode, wherein the capillary and capillary electrode are configurable so as to ionize the nebulized fluid sample by electrospray ionization and the second electrode is configurable so as to ionize the nebulized sample by atmospheric pressure chemical ionization.

Interchangeable ion source for electrospray and atmospheric pressure chemical ionization

A system for analyzing ions comprises: an ion source; a FAIMS cell comprising: (a) a gas inlet; (b) an outer electrode having a generally concave inner surface and comprising: (i) an ion inlet operable to receive the ions from the ion source and a carrier gas from the gas inlet; and (ii) an ion outlet; and (c) an inner electrode having a conduit therethrough and having a generally convex outer surface disposed in a spaced-apart and facing arrangement relative to the inner surface of the outer electrode defining at least one annular on separation region therebetween; and a mass analyzer for mass analyzing ions transmitted by the FAIMS cell through the ion outlet, wherein the inner electrode is moveable between a first position and a second position, the first and second positions facilitating movement of the ions through the at least one annular ion separation region and the conduit, respectively.

FAIMS having a displaceable electrode for on/off operation

A High Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) apparatus comprises (a) a first and a second gas inlet; (b) an expansion chamber receiving ions from an ion source and the first and second gas flows from the first and second gas inlets, respectively; (c) an outer electrode having a generally concave inner surface and comprising: (i) an ion inlet operable to receive, from the expansion chamber, the ions and a combined gas flow comprising portions of the first and second gas flows; and (ii) an ion outlet; and (d) an inner electrode having a generally convex outer surface that is disposed in a spaced-apart and facing arrangement relative to the inner surface of the outer electrode for defining an ion separation region therebetween, wherein the combined gas flow and a portion of the ions travel through the ion separation region from the ion inlet to the ion outlet.

Control of gas flow in high field asymmetric waveform ion mobility spectrometry

A system for analyzing ions comprises: an ion source; a FAIMS cell comprising: (a) a gas inlet; (b) an outer electrode having a generally concave inner surface and comprising: (i) an ion inlet operable to receive the ions from the ion source and a carrier gas from the gas inlet; and (ii) an ion outlet; and (c) an inner electrode having a conduit therethrough and having a generally convex outer surface that is disposed in a spaced-apart and facing arrangement relative to the inner surface of the outer electrode for defining an ion separation region therebetween; and a mass analyzer for mass analyzing ions transmitted by the FAIMS cell through the ion outlet, wherein the inner electrode is moveable between a first position and a second position, the first position facilitating movement of the ions through the ion separation region, the second position facilitating movement of the ions through the conduit.

A combined rf-only/FAIMS apparatus is disclosed for use in mass spectrometry and other applications. The disclosed apparatus includes a plurality of curved electrodes arranged around a central ion transmission channel. FAIMS functionality is removed electronically when not desired by application of radio frequency (rf) waveforms to the curved electrodes.

Quadrupole FAIMS apparatus

A high field asymmetric waveform ion mobility spectrometer (FAIMS) includes at least two focusing electrodes that are separated one from the other by a gap, which decreases in width along a direction of ion flow. Within the gap is disposed an electrode assembly including a first electrode and a second electrode, approximately flat surfaces of the first and second electrodes facing one another so as to define a space of approximately uniform thicknesses therebetween. During use electrical signals are applied via an electrical contact on at least one of the first electrode and the second electrode, and on each one of the at least two focusing electrodes. The electrical signals are for establishing electrode electric field conditions within the space between the first electrode and the second, for selectively transmitting ions therethrough and for directing the selectively transmitted ions in a direction away from one of the at least two focusing electrodes and toward a central portion of the space.

Flat plate FAIMS with lateral ion focusing

A FAIMS cell has an elongated inner electrode with a longitudinal axis extending along a first direction. The inner electrode has a curved outer surface that defines a circle when viewed in a cross section that is taken in a plane normal to the longitudinal axis, which itself passes through the center of the circle so defined. An outer electrode having an inner surface is disposed in a spaced-apart facing relationship relative to the outer surface of the inner electrode so as to define an analytical gap therebetween. A first ion inlet orifice is defined through a first portion of the outer electrode, and an ion outlet orifice is defined through a second portion of the outer electrode. In particular, the first ion inlet orifice has a first ion injection axis that does not pass through the center of the circle. Furthermore, the second electrode does not have defined through any portion thereof an ion inlet orifice having an ion injection axis that passes through the center of the circle.

FAIMS cell having an offset ion inlet orifice

A method for analyzing ions includes providing a desolvation chamber in communication with an analytical gap of a FAIMS analyzer, via an ion inlet orifice. A flow of ions is introduced into the desolvation chamber along a flow path that is toward the ion inlet orifice and into the analytical gap of the FAIMS analyzer. A flow of a desolvation gas is provided into the desolvation chamber via a first gas inlet, such that a portion of the flow of the desolvation gas is counter-current to the flow of ions. A flow of a carrier gas is provided separately via a second gas inlet, which is defined downstream relative to the desolvation chamber. In particular, the composition of the carrier gas is different than the composition of the desolvation gas. Accordingly, the flow of the carrier gas is provided substantially into the analytical gap for transporting ions along a path between the ion inlet orifice and an ion outlet orifice of the analytical gap.

FAIMS cell with separate desolvation and carrier gas inlets

A combined rf-only/FAIMS analyzer is disclosed for use in mass spectrometry and other applications. The disclosed apparatus includes a plurality of flat-plate electrodes arranged around a longitudinal axis of the apparatus so as to define generally a parallelogram in a cross section taken in a plane that is normal to the longitudinal axis. FAIMS is removed electronically when not desired by application of radio frequency (rf) waveforms to the flat-plate electrodes.

A FAIMS cell including one of side-to-side cylindrical geometry electrodes and stacked-plate electrodes is adapted with a medial surface feature for focusing ions along a lateral direction within an ion separation region of the FAIMS cell. The medial surface feature is provided as one of a recessed channel within an electrode surface and a protruding ridge extending from an electrode surface. The medial surface feature is aligned with a defined aggregate direction of ion travel within the ion separation region for focusing ions along the lateral direction in opposition to the tendency of ions to spread out as a result of space charge repulsion, ion-ion repulsive forces, diffusion and gas flows. The electrical field and fluid dynamic effects produced by the medial surface feature beneficially affect ion transmission efficiency through the FAIMS cell.

Growing community of inventors

Los Altos, CA, United States of America

Michael William Belford