Abstract: A method of operating a quadrupole device is disclosed that comprises operating the quadrupole device in a first mode of operation, passing ions into the quadrupole device while the quadrupole device is operated in the first mode of operation, and then operating the quadrupole device in a second mode of operation. Operating the quadrupole device in the second mode of operation comprises applying one or more drive voltages to the quadrupole device, and operating the quadrupole device in the first mode of operation comprises applying one or more reduced drive voltages or not applying one or more drive voltages to the quadrupole device.

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 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 mass spectrometry is disclosed comprising separating ions temporally in a first device and analysing the mass or mass to charge ratio of the ions or of product or fragment ions derived from the ions in a mass or mass to charge ratio analyser disposed downstream of the first device. The method further comprises obtaining a first set of drift times for the ions through the first device by measuring ion arrival times and determining the transit time of the ions and/or of the product or fragment ions through one or more intermediate regions or devices disposed between the first device and the mass to charge ratio analyser. The method further comprises obtaining a second set of drift times for the ions through the first device by correcting the first set of drift times to account for the determined transit times.

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 Time of Flight mass spectrometer is disclosed wherein a fifth order spatial focusing device is provided. The device which may comprise an additional stage in the source region of the Time of Flight mass analyser is arranged to introduce a non-zero fifth order spatial focusing term so that the combined effect of first, third and fifth order spatial focusing terms results in a reduction in the spread of ion arrival times ?T of ions arriving at the ion detector.

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 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: 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.

Abstract: A method of ion mobility spectrometry is disclosed comprising: transmitting a plurality of ions to an ion mobility separator 6; modulating the introduction of the ions into the ion mobility separator 6 at a first modulation frequency; separating the ions that enter the ion mobility separator 6 according to ion mobility; detecting ions that have exited the ion mobility separator with a detector of a time of flight mass analyser 8; varying the first modulation frequency with time; recording the intensity of the ion signal output from the detector to produce recorded data; modulating the recorded data as a function of the time that the data was recorded and at a second modulation frequency, wherein the second modulation frequency is varied as a function of the time that the data was recorded; and determining, from the variation in intensity of the ion signal in the modulated data as a function of the second modulation frequency, the ion mobilities of the ions that have been detected.

Abstract: A mass or mass to charge ratio selective ion trap is disclosed which directs ions into a small ejection region. A RF voltage acts to confine ions in a first (y) direction within the ion trap. A DC or RF voltage acts to confine ions in a second (x) direction. A quadratic DC potential well acts to confine ions in a third (z) direction within the ion trap. The profile of the quadratic DC potential well progressively varies along the second (x) direction.

Abstract: A method of mass spectrometry is disclosed comprising digitising a first signal output from an ion detector to produce a first digitised signal, detecting one or more peaks in the first digitised signal and determining a first area S0 or a first intensity I0 of the one or more peaks and a first arrival time T0 of the one or more peaks thereby forming a first list of data pairs and determining whether or not the first area S0 or the first intensity I0 exceeds a first threshold area Smax or a first threshold intensity Imax. The first threshold area Smax and the first threshold intensity Imax correspond respectively to a peak area and a peak intensity indicative of substantially simultaneous arrival of two ions which the ion detector is unable to resolve.

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 mass analyzer is disclosed comprising an annular ion guide comprising a first annular ion guide section and a second annular ion guide section, wherein the annular ion guide comprises: (i) an inner cylindrical electrode arrangement which is axially segmented and comprises a plurality of first electrodes and (ii) an outer cylindrical electrode arrangement which is axially segmented and comprises a plurality of second electrodes. Ions are introduced into the first annular ion guide section so that the ions form substantially stable circular orbits. Ions are orthogonally accelerated from the first annular ion guide section into the second annular ion guide section and one or more parabolic DC potentials are maintained along a portion of the second annular ion guide section so that ions undergo simple harmonic motion. An inductive ion detector is arranged and adapted to detect ions within the second annular ion guide section.

Abstract: A mass spectrometer is disclosed comprising a RF ion guide wherein in a mode of operation a continuous, quasi-continuous or pulsed beam of ions is orthogonally sampled from the ion guide and wherein the continuous, quasi-continuous or pulsed beam of ions is not axially trapped or otherwise axially confined within the RF ion guide. The ion guide is maintained, in use, at a pressure selected from the group consisting of: (i) 0.0001-0.001 mbar; (ii) 0.001-0.01 mbar; (iii) 0.01-0.1 mbar; (iv) 0.1-1 mbar; (v) 1-10 mbar; (vi) 10-100 mbar; and (vii) >100 mbar.

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 introducing and ejecting ions from an ion entry/exit device is disclosed. The ion entry/exit device has at least two arrays of electrodes. 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 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 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.

Abstract: A Time of Flight mass analyzer is disclosed comprising an annular ion guide having a longitudinal axis and comprising a first annular ion guide section and a second annular ion guide section. Ions are introduced into the first annular ion guide section so that the ions form substantially stable circular orbits within the first annular ion guide section about the longitudinal axis. An ion detector is disposed within the annular ion guide. Ions are orthogonally accelerated in a first axial direction from the first annular ion guide section into the second annular ion guide section. An axial DC potential is maintained along at least a portion of the second annular ion guide section so that the ions are reflected in a second axial direction which is substantially opposed to the first axial direction. The ions undergo multiple axial passes through the second annular ion guide section before being detected by the ion detector.

Abstract: A method of separating ions according to mass to charge ratio is disclosed. The method comprises: providing a separation device comprising a plurality of electrodes; applying one or more transient DC voltages or potentials to at least some of said electrodes in order to urge ions in a first direction through said separation device; and providing a gas flow in a second direction which is substantially inclined or opposed to said first direction. The opposed gas flow unexpectedly improves the mass to charge ratio separation resolution of the device.

Abstract: A mass spectrometer is disclosed comprising a first mass filter comprising a plurality of electrodes and a first device arranged and adapted to generate an axial force which drives at least some ions axially through or along the first mass filter and a quadrupole mass filter or mass analyzer arranged downstream of the mass filter.