Bruker Daltonik Gmbh

Other

Bruker Dalton K Gmbh

Andreas Brekenfeld

Jochen Franzen

Ralf Hartmer

Christoph Gebhardt

Craig M Whitehouse

Melvin Andrew Park

Michael Schubert

Carsten Stoermer

Mark Ridgeway

Desmond Allen Kaplan

Christian Gebhardt

Thomas Wehkamp

Martin Engel

The invention relates to hybrid IMS/MS systems and provides hybrid IMS/MS system comprising an RF funnel, an ion mobility analyzer and a mass analyzer wherein the RF funnel is arranged non-collinearly to the ion mobility analyzer, preferably a TIMS analyzer (TIMS=trapped ion mobility spectrometry).

Hybrid mass spectrometric system

The invention relates to an ionization chamber for connection to a mass spectrometer. The ionization chamber has a temperature-control block with a gas inlet and a gas channel which starts at the gas inlet and leads into a gas outlet. A temperature-control device is positioned along the gas channel and ensures that a gas flowing in the gas channel is brought to a specific temperature, i.e. it is heated or cooled, before it enters the ionization chamber. The temperature-control block has a formed part into which a structure of the gas channel is incorporated and which is fabricated by means of a sol-gel process, for example out of a glass or ceramic material.

Ionization chamber with temperature-controlled gas feed

The invention involves electrospray ionization of dissolved substances at atmospheric pressure in the ion source of a mass spectrometer. A chip with a multitude of spray nozzles is proposed, where each individual spray nozzle is surrounded by several sheath gas nozzles, preferably in a symmetric arrangement, for the jet-like introduction of a sheath gas. A shared attracting-voltage electrode is positioned substantially opposite the spray nozzles. The attracting-voltage electrode may have a tapering (e.g. funnel-shaped) opening above each spray nozzle so that the sheath gas jets are forced to closely envelop the spray jet, which is comprised of ions and very fine droplets. Heavier ions and droplets are thus prevented from discharging on the surfaces of the openings of the attracting-voltage electrode. Special measures can be taken to make all spray nozzles spray uniformly and to supply them with substance peaks from chromatographic or electrophoretic separators as simultaneously as possible.

Multi-nozzle chip for electrospray ionization in mass spectrometers

The invention proposes a method for the collective ejection of ions from a 3D RF ion trap with a ring electrode and two end cap electrodes, which comprises the following steps: (a) the RF voltage of a high-quality resonant circuit applied to the ring electrode is replaced with a second RF voltage at the two end cap electrodes which can be changed or switched faster than the high voltage at the ring electrode, keeping the ions stored, (b) the second RF voltage at the end cap electrodes is then switched down or off abruptly, releasing the ions, and (c) the released ions are ejected through an opening in one of the end cap electrodes by switching on a DC voltage on at least one of the end cap electrodes.

Ejection of ion clouds from 3D RF ion traps

In an RF quadrupole ion trap having electrodes to which RF voltages are applied, ions having m/z ratios outside of a predefined narrow range of charge-related masses m/z are removed from the trap by applying a DC voltage pulse to at least one of the trap electrodes to remove from the trap the ions with high values of charge-related masses. The DC voltage pulse is preferably applied in combination with a variation of the RF voltage amplitudes to simultaneously remove from the trap ions of low charge-related masses. The DC and RF voltage amplitudes are changed in such a manner that any excitation of ions having charge-related masses within the predefined range by frequency mixtures is avoided.

Isolation of ions in overloaded RF ion traps

Analyte ions, particularly biopolymer ions, stored in an RF ion trap are ergodically fragmented by bombarding the analyte ions with collision ions, for example medium-mass, mono-atomic ions having a charge of opposite polarity to the charge of the analyte ions. Since the analyte ions are not fragmented by accelerating and/or exciting them to oscillations, as is the case with conventional collision-induced dissociation, the RF voltage of the ion trap can be set low enough that daughter ions with light charge-related masses that are produced by the fragmentation can also remain trapped in the ion trap.

Fragmentation of analyte ions by collisions in RF ion traps

An apertured diaphragm disposed with an RF ion guide includes at least one of a weakly conductive solid dielectric material and a non-conducting dielectric with a weakly conducting surface layer.

Apertured diaphragms between RF ion guides

The invention relates to determining the masses from the time-of-flight values of ions in time-of-flight mass spectrometers where the accelerating voltage for the ions is not applied permanently, but is switched on at a certain time, resulting in a temporally changing acceleration for a short time after the voltage has been switched on. An aspect of the invention includes formally describing the effect of the temporally changing acceleration on the calibration curve&#x2014;an effect which cannot be subjected to a strict mathematical-analytical calculation&#x2014;by introducing a 'reduced mass' m&#x2212;minstead of the mass m. The mass reduction factor mdoes not describe a real mass difference, but a mass-dependent shortfall in the final kinetic energy after the ions have passed through the acceleration, a shortfall which can be observed with the temporally changing acceleration. This surprisingly simple formalism makes it possible to calculate the mass of the ions over a wide mass range and with an accuracy of approximately one part per million of the mass, using a calibration curve containing only four to six calibrated coefficients.

Calibration curves for time-of-flight mass spectrometers

In an RF ion trap, analyte ions are fragmented by applying a moderately high RF storage voltage to the trap. The ions are then excited via dipolar excitation, and after a short time, the ions are forced into a resting state, again using dipolar excitation. The RF storage voltage is then rapidly reduced to a low value thereby making it possible to store small fragment ions produced by ergodic decompositions that occur subsequent to the reduction of the RF storage voltage.

Collision-induced decomposition of ions in RF ion traps

The invention relates to methods for the measurement of fragment ion spectra in ion trap mass spectrometers in which fragment ions below a cut-off mass cannot normally be measured. The invention consists in measuring mass spectra including light fragment ions by briefly conducting the collisionally induced fragmentation&#x2014;which is always brought about by a large number of collisions&#x2014;at an unusual high RF storage voltage, which produces collisions more energetically than by conventional fragmentation, and then switching the RF voltage to a low RF voltage in a fast but controlled procedure. In this way light fragment ions are produced by double cleavages from metastable fragment ions with a certain half-life time. Since the cut-off mass for the storage capability is proportional to the RF storage voltage, reducing the RF storage voltage means that the light fragment ions can also be kept and measured in the ion trap.

Measurement of light fragment ions with ion traps

The invention relates to methods and devices for the transport of ions generated in gases near atmospheric pressure into the vacuum system of a mass spectrometer. Instead of the single capillary customary in commercial instruments, the invention uses a multichannel plate with hundreds of thousands of very short and narrow capillaries, whose total gas throughput is no higher than that of a normal single capillary. The large-area take-up of ions in the gas flow greatly increases the transfer yield. If the channels are conductive, this prevents the inside surfaces becoming charged. An ion funnel can separate the ions from the gas flow in the vacuum and focus them. Gas-dynamic focusing in an electric decelerating field reduces ion losses caused by wall collisions and prevents very light ions (protons, water clusters) from entering the vacuum. Staged multichannel plates reduce pumping requirements.

Apparatus and method for the transport of ions into a vacuum

The invention relates to a method and instrument for the fragmentation of large molecular analyte ions, preferably biopolymer ions, by reactions between multiply charged positive analyte ions and negative reactant ions in RF quadrupole ion traps. Some of these reactions involve electron transfer reactions with subsequent dissociation of the biopolymer analyte ions, and some involve the loss of a proton, leading to stable product ions. The invention can use any type of ion traps, particularly three-dimensional RF quadrupole ion traps, for the reactions between positive and negative ions. The fragmentation yield can be increased because ions that remain stable as radical cations after transfer of an electron are further fragmented by collisionally induced fragmentation, forming fragment ions that are typical of electron transfer, and not those typical of collisionally induced fragmentation. The invention preferentially introduces positive ions and negative ions into the ion trap sequentially through the same aperture.

Ion fragmentation by electron transfer in ion traps

The invention relates to RF voltage-operated ion guides based on stacked apertured diaphragms. The invention provides ion guides consisting of diaphragm stacks that permit the ion beam to be shaped in cross-section so that it corresponds to the acceptance profile of the subsequent section of the device, therefore yielding optimal ion transmission. For this purpose, at least some of the diaphragms in the diaphragm stacks do not have circular openings, but instead have openings which shape the cross section of the emerging ion beam in the desired manner. It is possible, for instance, to obtain elliptical beam cross sections, divided beams or beams focused to the shape of a fine thread at the output of the diaphragm stacks.

Ion guides with RF diaphragm stacks

The invention relates to the removal of electronic noise from mass spectra which are scanned as single spectra and added together to give a sum spectrum. The invention consists in removing the noise in the single spectra and not in the sum spectrum since ion signals and electronic noise can only be distinguished in the single spectra.

Method and apparatus for producing mass spectrometer spectra with reduced electronic noise

The invention relates to ion-guide systems for the transfer, cooling, fragmentation, selection and temporary storage of ions. The invention consists in embedding systems, made from one or more straight or curved rods to which a single or multiphase radio frequency voltage is applied, in an external enveloping dc potential. The combination of the ion-repelling radio-frequency pseudo field around the rods and the external dc voltage field represents a new category of ion-guide systems. With external dc voltage fields, whose strength or penetration into the interior of the rod system varies along the axis of the system, the ions can be collected or propelled along the axis of the system. Filling the system with collision or damping gas allows the ions to be fragmented and cooled without any losses and the phase space volumes of the ions to be greatly reduced.

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Bremen, Germany

Andreas Brekenfeld