A method of mass spectrometry is disclosed wherein one or more relatively abundant or intense species of ions in a first population of ions are selectively attenuated so as to form a second population of ions. The total ion current of the second population of ions is then adjusted so that the ion current corresponding to ions which are onwardly transmitted to a mass analyser comprising an ion detector is within the dynamic range of the ion detector.

A method of mass or ion mobility spectrometry is disclosed comprising: releasing ions from an ion trapping volume into an ion separation region; separating the ions along a longitudinal direction according to a physicochemical property; and compressing the ion beam in a direction orthogonal to the longitudinal axis. The method enables the ions to be focussed without increasing the charge density and hence space-charge effects to undesirable levels.

A method of mass and/or ion mobility spectrometry is disclosed that comprises accumulating ions for a first period of time (T1) one or more times so as to form one or more first groups of ions, accumulating ions for a second period of time (T2) one or more times so as to form one or more second groups of ions, wherein the second period of time (T2) is less that the first period of time (T1), analysing the one or more first groups of ions to generate one or more first data sets, analysing the one or more second groups of ions to generate one or more second data sets, and determining whether the one or more first data sets comprise saturated and/or distorted data. If it is determined that the one or more first data sets comprise saturated and/or distorted data, then the method further comprises replacing the saturated and/or distorted data from the one or more first data sets with corresponding data from the one or more second data sets.

A mass spectrometry apparatus includes an ion source, an ion trap and a mass spectrometer controller. The ion source is configured to generating ions. The ion trap is configured to trap ions within a RF field; eject unwanted ion while retaining target ions; and fragment target ions. The mass spectrometer controller is configured to determine an injection time for the ion trap based on a precursor ion flux and a product ion flux; fill the ion trap with ions from the ion source for an amount of time equal to the injection time; isolate target precursor ions in the ion trap; fragment the target precursor ions to generate product ions; and mass analyzing the product ions.

A method of analyzing ions by ion mobility separation is disclosed. The method comprises controlling the amount of charge within an ion trap and then pulsing the ions from the ion trap into an ion mobility separator. This enables the charge injected into the ion mobility separator to be controlled and hence prevents space-charge interactions between the ions from distorting the ion mobility peaks detected by the detector.

A mass spectrometer that includes a mass filter and a TOF mass analyzer receives the ion beam from an ion source device that ionizes a compound of a sample. The mass filter selects a precursor ion mass range and the mass analyzer mass analyzes the mass range. A continuous flow of selected precursor ions is maintained between the mass filter and the mass analyzer. A first set of parameters is applied to the mass spectrometer to produce a resolution above a first resolution threshold. A space charge effect is detected by determining if the measured TIC exceeds a TIC threshold or the measured resolution is less than the first resolution threshold. If a space charge effect is detected, at least one precursor ion transmission window with a width smaller than the mass range is applied to the ion beam by the mass filter and mass analyzed to reduce the space charge.

A charge detection mass spectrometer includes an ion trap configured to receive and store ions therein and to selectively release stored ions therefrom, and an electrostatic linear ion trap (ELIT) spaced apart from the ion trap, the ELIT including first and second ion mirrors and a charge detection cylinder positioned therebetween, and means for selectively controlling the ion trap to release at least some of the stored ions therefrom to travel toward and into the ELIT, and for controlling the first and second ion mirrors in a manner which traps in the ELIT a single one of the ions traveling therein and causes the trapped ion to oscillate back and forth between the first and second ion mirrors each time passing through and inducing a corresponding charge on the charge detection cylinder.

An object of the present disclosure is to provide a method for controlling a mass analyzer. According to the method, sensitivity reduction in a high ion concentration region can be prevented without changing a dwell time for each data point. In the method for controlling a mass analyzer according to the present disclosure, starting collecting data is executed at the same time interval, and a time length for collecting the data varies depending on a degree of space charge generated in a prefilter or a degree of sensitivity reduction of the mass analyzer caused by the space charge.

This disclosure describes a method of adjusting the amplitude of broadband waveforms for isolation, especially during injection to a multipole trapping device. Isolation during injection to a trapping device is known to be an effective way of accumulating a desired population of ions while rejecting unwanted species. The waveform amplitude required to eject unwanted species varies as a function of isolation time, but using automated gain control, the time required to accumulate a given population of ions may vary over several orders of magnitude. Thus, when the injection times are very long, precursor ions of interest are resonated for a long time and may be inadvertently ejected from the trap, using conventional methods. By setting the waveform amplitude lower for longer accumulation times, good isolation efficiency can be maintained for the precursor, while still rejecting unwanted ions.

A linear ion trap includes at least two discrete trapping regions for processing ions and at least one gas pulse valve for applying pulses of gas to dynamically control pressure in the at least two discrete trapping regions. A RF electrical potential generator produces two RF waveforms, each applied to a pair of pole electrodes of the linear ion trap forming a RF trapping field component to trap ions radially. A multi-output DC electrical potential generator produces multiple DC field components superimposed to the RF trapping field component and distributed across the length of the linear ion trap to control ions axially. A control unit is configured to switch the DC electrical potentials and corresponding DC field components collectively forming a first trapping region of the at least two discrete trapping regions that is populated with ions to alter ion potential energy from a first level to a second level, and to enable at least a first ion processing step in at least one of the first and second levels.