Leco Corporation

University of New Hampshire

Anatoli N Verentchikov

Mikhail Yavor

Viatcheslav Artaev

Joel C Mitchell

Viatcheslav Arteav

Bruce B Reinhold

Yuri Khasin

Mikhail I Yavor

A multi-reflecting, time-of-flight (MR-TOF) mass spectrometer including two quasi-planar electrostatic ion mirrors extended along drill direction (Z) and formed of parallel electrodes, separated by a field free region. The MR-TOF includes a pulsed ion source to release ion packets at a small angle to X-direction which is orthogonal to the drill direction Z. Ion packets are reflected between ion mirrors and drill along the drift direction. The mirrors are arranged to provide time-of-flight focusing ion packets on the receiver. The MR-TOF mirrors provide spatial focusing M the Y-direction orthogonal to both drift direction Z and on injection direction X. In a preferred embodiment, at least one mirror has a feature providing periodic spatial focusing of ion packets in the drift Z-direction.

Quasi-planar multi-reflecting time-of-flight mass spectrometer

A multi-reflecting time-of-flight (MR-TOF) mass spectrometer, which includes two quasi-planar electrostatic ion mirrors extended along drift direction (Z) and is formed of parallel electrodes, separated by a field-free region. The MR-TOF includes a pulsed ion source to release ion packets at a small angle to X-direction which is orthogonal to the drift direction Z. Ion packets are reflected between ion mirrors and drift along the drift direction. The mirrors are arranged to provide time-of-flight focusing ion packets on the receiver. The MR-TOF mirrors provide spatial focusing in the Y-direction orthogonal to both drift direction Z and ion injection direction X. In a preferred embodiment, at least one mirror has a feature providing periodic spatial focusing of ion packets in the drift Z-direction.

Ion manipulation systems include ion repulsion by an RF field penetrating through a mesh. Another comprises trapping ions in a symmetric RF field around a mesh. The system uses macroscopic parts, or readily available fine meshes, or miniaturized devices made by MEMS, or flexible PCB methods. One application is ion transfer from gaseous ion sources with focusing at intermediate and elevated gas pressures. Another application is the formation of pulsed ion packets for TOF MS within trap array. Such trapping is preferably accompanied by pulsed switching of RF field and by gas pulses, preferably formed by pulsed vapor desorption. Ion guidance, ion flow manipulation, trapping, preparation of pulsed ion packets, confining ions during fragmentation or exposure to ion to particle reactions and for mass separation are disclosed. Ion chromatography employs an ion passage within a gas flow and through a set of multiple traps with a mass dependent well depth.

Method and apparatus for ion manipulation using mesh in a radio frequency field

The disclosed apparatus includes a multi-reflecting time-of-flight mass spectrometer (MR-TOF MS) and an orthogonal accelerator. To improve the duty cycle of the ion injection at a low repetition rate dictated by a long flight in the MR-TOF MS, multiple measures may be taken. The incoming ion beam and the accelerator may be oriented substantially transverse to the ion path in the MR-TOF, while the initial velocity of the ion beam is compensated by tilting the accelerator and steering the beam for the same angle. To further improve the duty cycle of any multi-reflecting or multi-turn mass spectrometer, the beam may be time-compressed by modulating the axial ion velocity with an ion guide. The residence time of the ions in the accelerator may be improved by trapping the beam within an electrostatic trap. Apparatuses with a prolonged residence time in the accelerator provide improvements in both sensitivity and resolution.

Multi-reflecting time-of-flight mass spectrometer with orthogonal acceleration

An imbalanced radio frequency (RF) field creates a retarding barrier near the exit aperture of a multipole ion guide, in combination with the extracting DC field such that the barrier provides an m/z dependent cut of ion sampling. Contrary to the prior art, the mass dependent sampling provides a well-conditioned ion beam suitable for other mass spectrometric devices. The mass selective sampling is suggested for improving duty cycle of o-TOF MS, for injecting ions into a multi-reflecting TOF MS in a zoom mode, for parallel MS-MS analysis in a trap-TOF MS, as well as for moderate mass filtering in fragmentation cells and ion reactors. With the aid of resonant excitation, the mass selective ion sampling is suggested for mass analysis.

Linear ion trap with an imbalanced radio frequency field

A multiple reflecting time-of-flight mass spectrometer (MR-TOF MS) and method of analysis are disclosed. The flight path of ions is folded along a trajectory by electrostatic mirrors. The longer flight path provides higher resolution while maintaining a moderate instrument size.

Multi-reflecting time-of-flight mass spectrometer and method of use

The present invention relates generally to a multi-reflecting time-of-flight mass spectrometer (MR TOF MS). To improve mass resolving power of a planar MR TOF MS, a spatially isochronous and curved interface may be used for ion transfer in and out of the MR TOF analyzer. One embodiment comprises a planar grid-free MR TOF MS with periodic lenses in the field-free space, a linear ion trap for converting ion flow into pulses and a C-shaped isochronous interface made of electrostatic sectors. The interface allows transferring ions around the edges and fringing fields of the ion mirrors without introducing significant time spread. The interface may also provide energy filtering of ion packets. The non-correlated turn-around time of ion trap converter may be reduced by using a delayed ion extraction from the ion trap and excessive ion energy is filtered in the curved interface.

Multi-reflecting time-of-flight mass spectrometer with isochronous curved ion interface

To provide comprehensive MS&#x2014;MS analysis, a time-nested separation is employed using two time-of-flight (TOF) mass spectrometers. Parent ions are separated in a slow and long TOF, operating at low ion energy (1 to 100eV), and fragment ions are mass analyzed in a fast and short TOF, operating at much higher keV energy. A low energy fragmentation cell between TOFand TOFis tailored to accelerate fragmentation and dampening steps, mostly by shortening the cell and employing higher gas pressure. Slow separation in TOFbecomes possible with an introduction of novel TOFanalyzers. Higher performance is expected with the use of novel hybrid TOFanalyzers, combining radio frequency (RF) and quadratic DC fields. An RF field retains low-energy ions within a TOFanalyzer, while a quadratic DC field improves resolution by compensating for a large relative energy spread.

Tandem time of flight mass spectrometer and method of use

A highly sensitive multiple stage (MS ) mass spectrometer is disclosed, capable of eliminating losses of ions during the isolation stage. Ions of interest are isolated (by m/z value) without rejecting ions of other m/z values, permitting the selected ions to be dissociated, while the rest of the ion population is available for subsequent isolation, dissociation and analysis of fragment ions. One preferred instrument includes a pulsed ion source coupled with a linear array of mass selective ion trap devices, at least one trap being coupled to an external ion detector. Each ion trap is configured with a storing cell for ion trapping interspersed between a pair of guarding cells, all aligned along their z axis. Radio frequency (RF) and direct current (DC) voltages are applied to electrodes of the ion trap device to retain ions within the storing cells. Each trapping cell has a sub-region in which the dynamical motion of the ion exhibits m/z-dependent resonance frequencies along the z direction, allowing the ion motion to be selectively excited by m/z value. The AC voltages can be combined with time-resolved changes in the applied DC voltages to enable individual trapping cell to be switched between ion trapping, mass selecting and ion fragmenting modes. Ions may be selectively transferred between ions traps, and selectively dissociated within each trap to enable a higher sensitivity MS operation. Various ion trapping devices are disclosed, namely, harmonic linear traps, Paul traps, and quadrupole traps.

Growing community of inventors

St. Petersburg, Russia

Anatoli N Verentchikov