77results about "Combination tandem in time" patented technology

A method and apparatus are provided for effecting multiple mass selection or analysis steps. Fundamentally, the technique is based on moving ions in different directions through separate components of a mass spectrometer apparatus. To effect different steps, a precursor ion is selected in a first mass selector, and then passed into a collision cell, to effect fragmentation or reaction with a gas, to generate fragment or product ions. The generated product ions are then passed back into the first mass selector, and preferably back into an upstream ion trap. The product ions then pass through the first mass selector again, to select a desired product ion, for further fragmentation and analysis. These steps can be repeated a number of times. A final mass analysis step can be effected in either a time-of-flight section or other mass analyzer. The invention enables conventional triple quadrupole mass spectrometers and QqTOF mass spectrometers to effect multiple MS steps.

Systems and methods are used to analyze a sample using variable mass selection window widths. A tandem mass spectrometer is instructed to perform at least two fragmentation scans of a sample with different mass selection window widths using a processor. The tandem mass spectrometer includes a mass analyzer that allows variable mass selection window widths. The selection of the different mass selection window widths can be based on one or more properties of sample compounds. The properties may include a sample compound molecular weight distribution that is calculated from a molecular weight distribution of expected compounds or is determined from a list of molecular weights for one or more known compounds. The tandem mass spectrometer can also be instructed to perform an analysis of the sample before instructing the tandem mass spectrometer to perform the at least two fragmentation scans of the sample.

This invention relates to a method of operating a charged particle trap in which ions undergo multiple reflections back and forth and / or follow a closed orbit around, usually, a set of electrodes. The invention allows high-performance isolation of multiple ion species for subsequent detection or fragmentation by deflecting ions out of the ion trap according to a timing scheme calculated with reference to the ions' periods of oscillation within the ion trap.

The invention belongs to the technical field of mass spectrometry and particularly relates to a cascade mass spectrometry method performed in an ion trap mass analyzer. The cascade mass spectrometry method performed in the ion trap mass analyzer specifically comprises three stages of ion selective segregation, collision induction dissociation and mass scanning and analyzing. According to the cascade mass spectrometry method performed in the ion trap mass analyzer, in the stage of collision induction dissociation, by changing the period of a radio frequency signal, namely changing the frequency of radio-frequency voltage loaded on an ion trap, parent ions with a certain mass-to-charge ratio undergo resonance excitation so as to obtain energy. The high-energy ions which undergo resonance excitation collide with neutral molecules in the ion trap and are dissociated, outcome ions are generated, and the cascade mass spectrometry is achieved. The cascade mass spectrometry method performed in the ion trap mass analyzer has the advantages that only arrangement of software can be used for changing the scanning period of the stage of collision induction dissociation in order to achieve collision induction dissociation, and thus, an experiment device and a method of cascade mass spectrometry can be obviously simplified.

A method and apparatus for tandem mass spectrometry is disclosed. Precursor ions are fragmented and the fragments are accumulated in parallel, by converting an incoming stream of ions from an ion source (10) into a time separated sequence of multiple precursor ions which are then assigned to their own particular channel of a multi compartment collision cell (40). In this manner, precursor ion species, being allocated to their own dedicated fragmentation cell chambers (41, 42 . . . 43) within the fragmentation cell (40), can then be captured and fragmented by that dedicated fragmentation chamber at optimum energy and / or fragmentation conditions.

A tandem mass spectrometer and method are described. Precursor ions are generated in an ion source (10) and an ion injector (21, 23) injects ions towards a downstream ion guide (50, 60) via a single or multi reflection TOF device (30) that separates ions into packets in accordance with their m / z. A single pass ion gate (40) in the path of the precursor ions between the ion injector (21, 23) and the ion guide (50, 60) is controlled so that only a subset of precursor ion packets, containing precursor ions of interest, is allowed onward transmission to the ion guide (50, 60). A high resolution mass spectrometer (70) is provided for analysis of those ions, or their fragments, which have been allowed passage through the ion gate (40). The technique permits multiple m / z ranges to be selected from a wise mass range of precursors, with optional fragmentation of one or more of the chosen ion species.

A mass spectrometer includes at least one ion selector, at least one collision cell, and an ion path switching device arranged to define a looped ion path around which ions derived from a sample may be sent multiple times (without reversal of ion travel) in order to effect a desired number of isolation / fragmentation cycles for MSn analysis. When the desired number of isolation / fragmentation cycles have been completed, the ion path switching device directs the ions to a detector or a separate mass analyzer for acquisition of a mass spectrum.

A single set of electrodes, wherein different electrical potentials are applied to the single set of electrodes at different times in order to perform both ion mobility-based spectrometry and mass spectrometry (MS) on a sample of ions, wherein the ions are processed by performing ion mobility-based spectrometry and mass spectrometry in any sequence, any number of times, and as isolated or superposed procedures in order to trap, separate, fragment, and / or analyze charged particles and charged particles derived from atoms, molecules, particles, sub-atomic particles and ions.

In a mass analysis of a sample, candidate compositions Y of a fragment ion produced by a dissociating operation are deduced from the mass of that fragment ion (Steps S6 to S9). If the number of the candidates Y is larger than a predetermined value (“No” in Step S10), the repetition counter of the dissociating operation is increased by one and the mass analysis of the fragment ion is performed again. If the number of the candidates is equal to or smaller than the predetermined value, the difference between the masses of the fragment ions before and after each mass-analyzing stage is calculated (Step S11). From this mass difference, the candidates Z of the desorption ion at each stage is deduced (Step S12). These candidates Z and Y are used to narrow down the candidate composition formulae X deduced from the mass of the precursor ion (Step S13). If the number of the candidates has decreased to one or become equal to or smaller than a predetermined value, the result is displayed (Steps S14 and S15). Thus reducing the number of the candidates to the lowest possible value, the present method provides the user with useful information for analyzing the molecular structure and / or composition of a sample having a large molecular weight.

A method of mass spectrometry is disclosed comprising performing a first analysis of a sample of ions wherein one or more parameters are scanned and / or ions are sorted according to one or more parameters during the first analysis. One or more ranges of interest of the one or more parameters from the first analysis are then automatically determined. A second subsequent analysis of the sample of ions is then automatically performed, wherein the second analysis is restricted to one or more of the ranges of interest of the one or more parameters.

The analyst previously enters the mass of a fragment that desorbs in the first dissociation with other analysis conditions, as the precursor ion selection reference for the second dissociation through the input unit 25. When the automatic analysis is started, the controller unit 21 sequentially performs the MS1 analysis, MS2 analysis and MS3 analysis. In the course of these analyses, the data processing unit 23 determines the valence of each ion species corresponding to the peaks appearing in the mass spectrum obtained by the MS1 analysis. In addition, after the MS2 analysis, the data processing unit 23 searches for the ion species in conformity with the selection reference in consideration of the determined valence, among the ion species corresponding to the peaks appearing in the mass spectrum by the MS2 analysis. The selected ion is determined as the precursor ion for the second dissociation in the MS3 analysis. In this manner, regardless of the valence of the target ion, the precursor ions to be selected and dissociated in each stage of the MSn analysis are automatically selected according to the mass of the fragment desorbed in the dissociation in the previous stage. Therefore, the analytical efficiency is improved and the highly accurate chemical structure information can be obtained.