Disclosed herein are various methods and apparatus for performing charge detection mass spectrometry (CDMS). In particular, techniques are disclosed for monitoring a detector signal from a CDMS device to determine how many ions are present in the ion trap (10) of the CDMS device. For example, if no ions are present the measurement can then be terminated early. Similarly, if more than one ion is present, the measurement can be terminated early, or ions can be removed from the trap (10) until only a single ion remains. Techniques are also provided for increasing the probability of there being a single ion in the trap (10). A technique for attenuating an ion beam is also provided.

A linear ion trap system includes a linear ion trap having at least two discrete trapping regions for processing ions. An RF electrical potential generator produces two RF waveforms 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 a first set of 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 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.

An ion trapping system is disclosed comprising an ion urging system for urging ions to spread out within an ion trapping region. Alternatively, the ion trapping system may deflect ions such that ions enter the ion trapping region at different locations. Alternatively, an ion deflector may be arranged upstream of, or at the entrance to, the ion trapping region, for deflecting ions such that ions enter the ion trapping region with different speeds so that the ions spread out within the ion trapping region.

The present disclosure provides a gas analysis device and a method for detecting sample gas. The gas analysis device includes: an ion mobility spectrometer including an ion mobility tube, an ion gate, a plurality of electrodes, a suppression grid, and a Faraday plate sequentially disposed in the ion mobility tube, wherein the Faraday plate is configured to receive sample ions discharged from the suppression grid, and the Faraday plate is provided with a through hole; a mass spectrometer; a gate valve disposed between the Faraday plate and an ion inlet of the mass spectrometer; and a controller configured to control an opening or closing of the gate valve to allow the sample ions discharged from the suppression grid to flow into the mass spectrometer through the through hole of the Faraday plate when the gate valve is opened.

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.

A method of injecting analyte ions into a mass analyser comprises: injecting analyte ions of a first charge and counter ions of a second charge into an ion trap; cooling the analyte ions and the counter ions simultaneously in the ion trap such that a spatial distribution of the analyte ions therein is reduced; and injecting the analyte ions as an ion packet from the ion trap into the mass analyser. A mass spectrometer controller is configured to: cause an ion source to inject an amount of analyte ions of a first charge and an amount of counter ions of a second charge into an ion trap; cause the ion trap to simultaneously cool the analyte ions and the counter ions in the ion trap, thereby reducing a spatial distribution of the analyte ions therein; and cause the ion trap to inject the analyte ions into a mass analyser.

A method of fragmenting ions comprises: injecting first ions of a first charge into an ion trap that includes an elongate multipole electrode assembly defining an elongate ion channel; radially confining the first ions within the ion channel by applying an RF pseudopotential to the electrode assembly and axially confining said ions to a first volume within the ion channel by applying a first potential well to the ion channel; injecting second ions of a second charge opposite to the first charge into the ion trap; axially confining the second ions to a second volume within the ion channel by applying a second potential well to the ion channel, the first potential well being within the second potential well; cooling the first and second ions in the ion trap; and allowing the ions to interact such that the first ions and/or second ions are fragmented to produce product ions.

Methods and systems for loading an ion trap are provided herein in which the total ion beam intensity and/or content of the ion beam are quickly interrogated so as to determine an optimum fill time for an ion trap. In various aspects, the methods and systems described herein are effective to prevent overfilling of the ion trap while decreasing the time associated with known techniques utilized to obtain a survey scan of the ion beam.

The present inventive concepts relate to determining an isotope ratio using mass spectrometry. Mass spectra of ions are obtained by generating ions, guiding the ions through a device having a mass transfer function that varies with ion current, providing at least some of the ions to a mass analyser and obtaining a mass spectrum of the ions and determining the ion current of the ions provided to the mass analyser. An isotope ratio of the ions is determined for each mass spectrum. Using the determined isotope ratio and determined ion current for each mass spectrum, a calibration relationship is determined that characterises the variation of the determined isotope ratios and the measured ion currents across the mass spectra. Then, a measured isotope ratio obtained at a determined ion current is adjusted using the calibration relationship to adjust the measured isotope ratio to an adjusted isotope ratio corresponding to a selected ion current.

The present inventive concepts relate to determining an isotope ratio using mass spectrometry. Mass spectra of ions are obtained by generating ions, guiding the ions through a device having a mass transfer function that varies with ion current, providing at least some of the ions to a mass analyzer and obtaining a mass spectrum of the ions and determining the ion current of the ions provided to the mass analyzer. An isotope ratio of the ions is determined for each mass spectrum. Using the determined isotope ratio and determined ion current for each mass spectrum, a calibration relationship is determined that characterizes the variation of the determined isotope ratios and the measured ion currents across the mass spectra. Then, a measured isotope ratio obtained at a determined ion current is adjusted using the calibration relationship to adjust the measured isotope ratio to an adjusted isotope ratio corresponding to a selected ion current.