Abstract: 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.

Abstract: 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.

Abstract: A method of introducing and ejecting ions from an ion entry/exit device (4) is disclosed. The ion entry/exit device (4) has at least two arrays of electrodes (20,22). The device is operated in a first mode wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays ((20,22) in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the device in the first direction. The device is also operated in a second mode, wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays (20,22) in a second, different direction such that a potential barrier moves along the array in the second direction and drives ions into and/or out of the device in the second direction. The device provides a single, relatively simple device for manipulating ions in multiple directions.

Abstract: A method and apparatus for separating ions according to a physicochemical property, such as ion mobility or mass-to-charge-ratio, is disclosed, comprising: repeatedly travelling a transient DC voltage along an ion guide; wherein the transient DC voltage has a first amplitude and first speed whilst it travels along a first region of the ion guide so as to urge ions having different values of said physicochemical property through said first region of the ion guide with different average speeds; and wherein, in a first mode, the transient DC voltage is travelled along a second region of the ion guide that is adjacent to said first region: (i) whilst having a second different amplitude; and/or (ii) at a second different non-zero speed; and/or (iii) at a substantially constant speed but with a different frequency to which it is repeatedly travelled along the first region; so that ions having a given value of said physicochemical property are urged through said second region of the ion guide at a different average

Abstract: A method of ion mobility and/or mass spectrometry is disclosed in which the ion mobility and/or mass to charge ratio of an ion is determined using an algorithm or relationship that relates the transit time or average ion velocity of the ion through an ion separation device in which one or more time-varying electric field is used to separate ions passing therethrough to one or more parameters for the device, the mass to charge ratio of the ion and the ion mobility of the ion.

Abstract: A method of introducing and ejecting ions from an ion entry/exit device (4) is disclosed. The ion entry/exit device (4) has at least two arrays of electrodes (20,22). The device is operated in a first mode wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays ((20,22) in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the device in the first direction. The device is also operated in a second mode, wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays (20,22) in a second, different direction such that a potential barrier moves along the array in the second direction and drives ions into and/or out of the device in the second direction. The device provides a single, relatively simple device for manipulating ions in multiple directions.

Abstract: A method is disclosed comprising: trapping ions in an ion trap (40); applying a first force on the ions within the ion trap in a first direction, said force having a magnitude that is dependent upon the value of a physicochemical property of the ions; applying a second force on these ions in the opposite direction so that the ions separate according to the physicochemical property value as a result of the first and second forces; and then pulsing or driving ions out of one or more regions of the ion trap.

Abstract: 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.

Abstract: A method is disclosed comprising: trapping ions in an ion trap (40); applying a first force on the ions within the ion trap in a first direction, said force having a magnitude that is dependent upon the value of a physicochemical property of the ions; applying a second force on these ions in the opposite direction so that the ions separate according to the physicochemical property value as a result of the first and second forces; and then pulsing or driving ions out of one or more regions of the ion trap.

Abstract: A method of filtering ions according to their ion mobility using a device is disclosed, the method comprising a plurality of electrodes and one or more voltage source(s) arranged and adapted to apply voltages to the plurality of electrodes, the method comprising, generating using the one or more voltage source(s) one or more local separation region(s), wherein ions can be separated within each local separation region according to their ion mobility, and moving each local separation region axially along the device with a certain velocity such that, for each local separation region, ions having a value of their ion mobility falling within a selected range are transmitted axially along the device with that local separation region whereas ions having higher and/or lower ion mobility falling outside that range escape the local separation region, wherein any ions that escape the local separation region(s) are removed from within the device and/or otherwise kept apart from those ions falling within the selected rang

Abstract: A method of mass filtering ions is disclosed comprising: providing a first, AC-only, mass filter (2); providing a second mass filter (4) downstream of the first mass filter; applying a first AC voltage (8) to electrodes of the first mass filter so as to radially confine ions between the electrodes, and applying a second AC voltage (10) between electrodes of the first mass filter (2) so as to radially excite some of said ions such that these ions are not transmitted; and using the second mass filter (4) to mass filter ions; wherein at any given time the second mass filter (4) only transmits ions having a first range of mass to charge ratios and filters out all other ions; and wherein the step of applying the at least one second AC voltage (10) to electrodes of the first mass filter (2) radially excites ions such that at least some ions having mass to charge ratios above said first range are not transmitted into the second mass filter.

Abstract: 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.

Abstract: A method of selecting ions comprises selecting ions corresponding to a target ion of interest by separating analyte ions according to their ion mobility, isolating first ions of the analyte ions, separating the first ions according to their ion mobility, and isolating second ions of the first ions. Preferably, the separation is accomplished by using a cyclic or closed-loop separator.

Abstract: A method of operating a quadrupole device (10) is disclosed. A voltage source (12) applies a main quadrupolar voltage, an auxiliary quadrupolar voltage and a dipolar voltage to the quadrupole device (10). This may be done such that only ions corresponding to a single X-band, X-band-like, Y-band or Y-band-like stability region are transmitted by the quadrupole device (10).

Abstract: A method of operating a quadrupole device (10) is disclosed. The quadrupole device (10) is operated in a mode of operation by applying a repeating voltage waveform comprising a main drive voltage and at least one auxiliary drive voltage is applied to the quadrupole device to the quadrupole device (10). The intensity of ions passing into the quadrupole device is varied with time in synchronisation with the repeating voltage waveform. This may be done such that the number of ions per unit phase which initially experience a phase within a first range of phases of the repeating voltage waveform is greater than the number of ions per unit phase which initially experience a phase within a second range of phases of the repeating voltage waveform.

Abstract: A method of filtering ions according to their ion mobility using a device is disclosed, the method comprising a plurality of electrodes and one or more voltage source(s) arranged and adapted to apply voltages to the plurality of electrodes, the method comprising, generating using the one or more voltage source(s) one or more local separation region(s), wherein ions can be separated within each local separation region according to their ion mobility, and moving each local separation region axially along the device with a certain velocity such that, for each local separation region, ions having a value of their ion mobility falling within a selected range are transmitted axially along the device with that local separation region whereas ions having higher and/or lower ion mobility falling outside that range escape the local separation region, wherein any ions that escape the local separation region(s) are removed from within the device and/or otherwise kept apart from those ions falling within the selected rang

Abstract: A method of operating a quadrupole device is disclosed that comprises operating the quadrupole device in a first mode of operation, and operating the quadrupole device in a second mode of operation. Operating the quadrupole device in the first mode of operation comprises applying one or more first voltages to the quadrupole device such that the quadrupole device is operated in an initial stability region and such that at least some ions are stable within the quadrupole device. Operating the quadrupole device in the second mode of operation comprises applying one or more second voltages to the quadrupole device such that the quadrupole device is operated in a different stability region and such that at least some of the ions that were stable within the quadrupole device in the first mode of operation are stable within the quadrupole device in the second mode of operation.

Abstract: A dual-mode ion detector for a mass and/or ion mobility spectrometer comprising a first conversion electrode (20) that is maintained, in use, at a negative potential and arranged for converting incident positive ions (32) into secondary electrons (34), and a second conversion electrode (22) that is maintained, in use, at a positive potential and arranged for converting incident negative ions (42) into secondary positive ions (44) and/or secondary electrons (74). The detector also comprises an electron detecting surface (26) and an entrance electrode (24) for drawing ions into the ion detector. The ion detector is switchable between a first mode for detecting positive ions and a second mode for detecting negative ions.

Abstract: A method of filtering ions (16) is disclosed comprising: providing an ion filter (6) having an ion entrance, an ion exit and a plurality of electrodes (18); applying an AC and/or RF voltage to at least a first electrode so as to generate a pseudo-potential barrier; and urging ions towards the pseudo-potential barrier as they travel from the entrance to the exit whilst maintaining the ion filter (6) at a pressure such that first ions are repelled by the pseudo-potential barrier and so are transmitted through the filter to said exit, whereas second ions having substantially the same mass to charge ratio as the first ions but a lower mass are not capable of being repelled by the pseudo-potential barrier and reaching said exit.

Abstract: A mass spectrometer is disclosed comprising a first device, a second device and a switch arranged and adapted: (i) to direct ions at a first time T1 to the first device and to substantially prevent ions from entering the second device; and (ii) to direct ions at a second later time T2 to the second device and to substantially prevent ions from entering the first device. At the first time T1 the second device may not be in an operational state to potentially optimally fragment, react, mass filter or otherwise process ions since the second device may be in a process of equilibration, changing state, re-filling, recharging, transition, replenishing, switching voltage or altering an operational parameter.