EP0765190B1 - Quadrupol mit einem von der resonanzfrequenz abweichenden angelegten signal - Google Patents

Quadrupol mit einem von der resonanzfrequenz abweichenden angelegten signal Download PDF

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Publication number
EP0765190B1
EP0765190B1 EP94920813A EP94920813A EP0765190B1 EP 0765190 B1 EP0765190 B1 EP 0765190B1 EP 94920813 A EP94920813 A EP 94920813A EP 94920813 A EP94920813 A EP 94920813A EP 0765190 B1 EP0765190 B1 EP 0765190B1
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Prior art keywords
field
supplemental
voltage
frequency
trapping
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French (fr)
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EP0765190A1 (de
EP0765190A4 (de
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Paul E. Kelley
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Shimadzu Corp
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Shimadzu Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/26—Mass spectrometers or separator tubes
    • H01J49/34—Dynamic spectrometers
    • H01J49/42—Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
    • H01J49/4205—Device types
    • H01J49/424—Three-dimensional ion traps, i.e. comprising end-cap and ring electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/26—Mass spectrometers or separator tubes
    • H01J49/34—Dynamic spectrometers
    • H01J49/42—Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
    • H01J49/426—Methods for controlling ions
    • H01J49/427—Ejection and selection methods
    • H01J49/4275—Applying a non-resonant auxiliary oscillating voltage, e.g. parametric excitation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/26—Mass spectrometers or separator tubes
    • H01J49/34—Dynamic spectrometers
    • H01J49/42—Stability-of-path spectrometers, e.g. monopole, quadrupole, multipole, farvitrons
    • H01J49/426—Methods for controlling ions
    • H01J49/427—Ejection and selection methods
    • H01J49/429—Scanning an electric parameter, e.g. voltage amplitude or frequency

Definitions

  • the invention relates to mass spectrometry methods in which ions are stably trapped in an ion trap and then selectively excited for detection. More particularly, the invention is a mass spbctrometry method in which ions are stably trapped by a trapping field, a supplemental field having frequency nearly matching (but different from) a frequency component of the frequency spectrum of oscillation of a selected trapped ion is superimposed with the trapping field to form a combined field, and the combined field is changed to sequentially excite selected stably trapped ions.
  • a combined field (comprising trapping and supplemental field components of different spatial form) is established in an ion trap, and the combined field is changed to resonantly excite stably trapped ions for detection.
  • US-A-3,065,640 describes a three-dimensional quadrupole ion trap with reference to Figure 1 thereof.
  • ions (known as “Parent ions") having mass-to-charge ratio (hereinafter denoted as “m/z”) within a selected range are isolated in an ion trap.
  • the stably trapped parent ions are then allowed or induced to dissociate (for example, by colliding with background gas molecules within the trap) to produce ions known as “daughter ions.”
  • the daughter ions are then ejected from the trap (typically by resonant ejection) and detected.
  • US-A-4,736,101 discloses an MS/MS method in which ions (having m/z's within a predetermined range) are trapped within a three-dimensional quadrupole trapping field (established by applying a trapping voltage across the ring and end electrodes of a quadrupole ion trap).
  • the trapping field is then scanned to eject unwanted parent ions (ions other than parent ions having a desired m/z) consecutively from the trap.
  • the trapping field is then changed again to become capable of storing daughter ions of interest.
  • the trapped parent ions are then induced to dissociate to produce daughter ions, and the daughter ions are ejected consecutively (sequentially by mass to-charge ratio) from the trap for detection.
  • US-A-4,736,101 teaches (at column 5, lines 16-42) establishment of a supplemental AC field (in addition to the trapping field) in the trap after the dissociation period, while the trapping voltage is scanned (or while the trapping voltage is held fixed and the frequency of the supplemental AC field is scanned).
  • the frequency of the supplemental AC field matches one of the components of the frequency spectrum of trapped ion oscillation, so that the supplemental AC field resonantly ejects a sequence of stably trapped ions from the trap as the secular frequency of each trapped ion (in the changing combined field) comes to match the frequency of the supplemental AC field.
  • US-A-4,882,484 teaches resonant ejection of stably trapped ions from a three-dimensional quadrupole (or approximately quadrupole) trap by scanning a combined field (having RF trapping and supplemental AC field components) that has been established in an ion trap region, such as by scanning the supplemental field's frequency, or holding the supplemental field frequency fixed while scanning a parameter of the trapping field.
  • a disadvantage of conventional resonant excitation techniques is that the changing parameters of the combined field must be carefully controlled during resonant excitation to avoid simultaneous ejection (loss of mass resolution) of different ion species and other undesirable interference effects. For example, consider a conventional resonant excitation method in which the frequency of the supplemental AC field component of the combined field is swept or scanned while other combined field parameters are held fixed.
  • the peak-to-peak amplitude of the AC supplemental voltage signal which establishes the supplemental AC field component must be carefully controlled (it must be maintained at a particular amplitude, to allow ions of interest to establish a resonance condition), and the rate of change of the supplemental voltage signal's AC frequency must also be carefully controlled, to avoid unacceptable mass resolution decrease due to simultaneous ejection of different ion species.
  • Quadrupole Mass Spectrometry and its Applications edited by P. H. Dawson, published by Elsevier, 1976, teaches at pp. 49-50 that if the frequency of the supplemental field applied during resonant excitation is close to, but different from the resonant frequency of a stably trapped ion, ions having different resonant frequency may be simultaneously excited for detection by the changing combined field. This is said to undesirably limit resolving power.
  • a trapping field (typically a quadrupole trapping field) is established in a trap region to stably trap ions, and one or more parameters of the trapping field are swept (or scanned) to cause trapped ions to become sequentially unstable.
  • Each stably trapped ion is characterized by parameters which map to a location within a stability diagram determined by the trapping field.
  • Fig. 2 is an example of a stability diagram for a quadrupole trapping field (Fig. 2 will be discussed in greater detail below).
  • ions having "a” and “q” parameters within the stability envelope can be stably trapped in the quadrupole trapping field (the parameters "e”:and “m” in Fig. 2 denote charge and mass, respectively).
  • the changing trapping field causes ions to become unstable and ejects them by moving the "a” and/or "q” parameters of a sequence of stably trapped ions outside the stability diagram (from within the stability diagram).
  • a supplemental field is established in the trap during sweeping or scanning of the trapping field (an AC oscillator is connected to one or both of the electrodes).
  • an AC oscillator is connected to one or both of the electrodes.
  • EP-A-350,159 teaches (at column 3, line 58, through column 4, line 25) application of a supplemental AC voltage across the end electrodes of a quadrupole ion trap while sweeping or scanning parameters of a quadrupole trapping field in the trap. It also teaches that the quadrupole trapping field parameters can be fixed and the supplemental AC frequency swept or scanned to accomplish mass selective instability ejection.
  • the quadrupole trapping field has an PS frequency component
  • the frequency of the supplemental AC voltage is preferably approximately equal to half the PS frequency (e.g., within plus or minus twenty percent of half the RF frequency)
  • the supplemental AC voltage has a frequency that matches the characteristic frequency of ion motion in the z (axial) direction.
  • a supplemental AC voltage is applied acros.s end electrodes of a quadrupole ion trap while sweeping or scanning parameters of a quadrupole trapping field in the trap (for example, during period C in the scan diagram shown in Fig. 2 of US-A-4,749,860).
  • the frequency of the supplemental AC voltage is chosen to resonantly eject a sequence of stably trapped ions.
  • other trapped ions are said to become sequentially unstable in the presence of the changing combined field.
  • a disadvantage of mass selective instability excitation is that the dynamic range for the number of ions that can be stored and mass analyzed with sufficient mass resolution is very limited. Performance of the inventive method avoids this disadvantage by extending the dynamic range, and also avoids the above-described disadvantage of conventional resonant excitation methods.
  • a supplemental field (which may be denoted as a “near resonance” or “off-resonance” supplemental field) is said to enable separation (filtering) of ions (by establishing a beat frequency condition) whose motion through the filter has such secular frequency from ions whose motion has slightly different secular frequency.
  • this reference does not suggest that an "off-resonance" field should be applied as one component of a changing combined field (established in a three-dimensional ion trap) to sequentially excite selected trapped ions (by a mechanism other than resonant excitation or mass selective instability excitation).
  • US-A-2,950,389 teaches that application of a near resonance supplemental field enables separation (filtering) of ions whose motion through the filter has a first secular frequency from ions whose motion has slightly different secular frequency.
  • the invention is a mass spectrometry method according to claim 1.
  • This method includes the steps of establishing a combined field (comprising a trapping field and a supplemental field), and changing at least one parameter of the combined field to excite ions trapped in the combined field sequentially (such as for detection).
  • the supplemental field is a periodically varying field having an "off-resonance" frequency, in the sense that the supplemental field frequency nearly matches (but differs from) frequency of a frequency component of the frequency spectrum of oscillation of an ion stably trapped by the trapping field alone.
  • the supplemental field is sometimes denoted herein as an "off-resonance" field.
  • Sequential ion excitation in accordance with the invention can rapidly eject a sequence of ions from a trap (or rapidly excite each ion in a sequence to a degree sufficient for a desired purpose such as detection) because the supplemental field will cause an increase in the trajectory of each ion in the sequence, due to the supplemental field having a sufficiently large peak-to-peak amplitude as to cause an increase in each ion mass trajectory to a desired magnitude within a desired short time period, without establishing a resonance condition, or before a resonance condition is established between the ion frequency of motion and the supplemental field frequency.
  • trapped ions are sequentially excited by holding the off-resonance field fixed while changing at least one parameter of the trapping field component of the combined field. In other embodiments, trapped ions are sequentially excited by changing (such as sweeping or scanning) at least one parameter of the off-resonance field while holding the trapping field fixed.
  • the peak-to-peak amplitude of the off-resonance field is kept sufficiently high to excite ions (via an off-resonance excitation mechanism) before they undergo resonant excitation.
  • the peak-to-peak amplitude of the off-resonance field should be kept sufficiently high to eject each of a sequence of trapped ions from the combined field via off-resonance excitation, before the oscillatory motion of any ion in the sequence undergoes resonant excitation in the changing combined field.
  • the rate of change of a combined field is controlled, and a peak-to-peak amplitude of a (fixed or changing) supplemental field (whose frequency matches frequency of a trapped ion) is also controlled to keep it at a value that matches a frequency of motion of the ion of interest with the frequency of the applied supplemental AC field such that a resonance condition is established for excitation.
  • simultaneous ejection of ions having different (but similar) m/z ratios i.e., via resonant excitation of an ion having a first m/z ratio with simultaneous off-resonance excitation of a second ion having a second m/z ratio slightly different than the first m/z ratio
  • simultaneous ejection of ions having different (but similar) m/z ratios i.e., via resonant excitation of an ion having a first m/z ratio with simultaneous off-resonance excitation of a second ion having a second m/z ratio slightly different than the first m/z ratio
  • the peak-to-peak amplitude of the supplemental field might be controlled to be less than one volt (to avoid interference effects such as that described above), whereas in a corresponding embodiment of the invention (one employing the same trapping field) the supplemental signal producing the off-resonance field could have peak-to-peak amplitude much greater than one volt (to enable mass analysis to be performed much more rapidly than in the conventional resonant excitation).
  • the changing combined field sequentially ejects selected trapped ions from the combined field for detection (or purposes other than detection).
  • the invention sequentially excites trapped ions without ejecting them from the combined field.
  • the combined field is established in a trap region surrounded by the ring electrode and two end electrodes of a three-dimensional quadrupole ion trap.
  • the combined field comprises a quadrupole trapping field produced by applying a fundamental voltage to one or more of the ring electrode and end electrodes, and a supplemental field produced by applying a supplemental AC voltage across the end electrodes.
  • the amplitude of an RF (or DC) component of the fundamental voltage can be scanned or otherwise changed while the supplemental AC voltage is applied across the end electrodes, or the quadrupole trapping field can be held fixed while a parameter of the supplemental AC voltage is scanned or otherwise changed, to sequentially off-resonantly excite ions having a range of m/z ratios for detection (or for any of a variety of other purposes, including inducement of ion reaction or dissociation in the presence of a buffer gas).
  • the trapping field (the trapping field component of the combined field) has a sinusoidal RF voltage component (of amplitude V and frequency ⁇ ) and optionally a DC voltage component (of amplitude U), and is applied to the ring and end electrodes of a quadrupole ion trap of the type shown in Fig. 1.
  • the quadrupole ion trap apparatus shown in Figure 1 is useful for implementing a class of preferred embodiments of the invention.
  • the Figure 1 apparatus includes ring electrode 11 and end electrodes 12 and 13.
  • a three-dimensional quadrupole trapping field is established in region 16 enclosed by electrodes 11-13, when fundamental voltage generator 14 is switched on (in response to a control signal from control circuit 31) to apply a fundamental voltage between electrode 11 and electrodes 12 and 13.
  • the fundamental voltage comprises a sinusoidal voltage having amplitude V and frequency ⁇ and optionally also a DC component of amplitude U.
  • ⁇ is typically within the radio frequency (RF) range.
  • Ion storage region 16 has radius r o and vertical dimension z o . Electrodes 11, 12, and 13 are common mode grounded through coupling transformer 32.
  • Supplemental AC voltage generator 35 can be switched on (in response to a control signal from control circuit 31) to apply a desired supplemental AC voltage across end electrodes 12 and 13 as shown (or alternatively, between electrode 11 and one or both of electrodes 12 and 13).
  • the supplemental AC voltage signal produced by generator 35 is selected to have a peak-to-peak amplitude V supp , and an "off-resonance" frequency ⁇ supp (to be described below).
  • the combined field comprising the quadrupole trapping field and the supplemental ("off-resonance") field established by the supplemental AC voltage can be changed to sequentially excite desired trapped ions in accordance with the invention, for detection (or other purposes).
  • the combined field is changed by scanning or sweeping (hereinafter denoted as "scanning") one or more parameters (V, ⁇ , U, V supp and ⁇ supp )of the combined field resulting from the voltage signals output from both elements 14 and 35 to sequentially excite desired trapped ions.
  • scanning one or more parameters (V, ⁇ , U, V supp and ⁇ supp )of the combined field resulting from the voltage signals output from both elements 14 and 35 to sequentially excite desired trapped ions.
  • Filament 17 when powered by filament power supply 18, directs an ionizing electron beam into region 16 through an aperture in end electrode 12.
  • the electron beam ionizes sample molecules within region 16, so that the resulting ions can be trapped within region 16 by the quadrupole trapping field.
  • Cylindrical gate electrode and lens 19 is controlled by filament lens control circuit 21 to gate the electron beam off and on as desired.
  • end electrode 13 has perforations 23 through which ions can be ejected from region 16 for detection by an externally positioned electron multiplier detector 24.
  • Electrometer 27 receives the current signal asserted at the output of detector 24, and converts it to a voltage signal, which is summed and stored within circuit 28, for processing within processor 29.
  • an in-trap detector is substituted.
  • an in-trap detector can comprise the trap's end electrodes themselves.
  • one or both of the end electrodes could be composed of (or partially composed of) phosphorescent material (which emits photons in response to incidence of ions at one of its surfaces).
  • the in-trap ion detector is distinct from the end electrodes, but is mounted integrally with one or both of them (so as to detect ions that strike the end electrodes without introducing significant distortions in the shape of the end electrode surfaces which face region 16).
  • in-trap ion detector is a Faraday effect detector in which an electrically isolated conductive pin is mounted with its tip flush with an end electrode surface (preferably at a location along the z-axis in the center of end electrode 13).
  • in-trap ion detectors can be employed, such as ion detectors which do not require that ions directly strike them to be detected (examples of this latter type of detector, which shall be denoted herein as an "in-situ detector,” include resonant power absorption detection means, and image current detection means).
  • each in-trap detector is supplied through appropriate detector electronics to processor 29.
  • generator 35 is replaced by a generator for applying a supplemental AC signal of sufficient power to the ring electrode (rather than to the end electrodes) to induce ions to leave the trap in radial directions (i.e., radially toward ring electrode 11) rather than in the z-direction.
  • a supplemental AC signal of sufficient power to the ring electrode (rather than to the end electrodes) to induce ions to leave the trap in radial directions (i.e., radially toward ring electrode 11) rather than in the z-direction.
  • Application of a high power supplemental signal to the trap in this manner to eject unwanted ions out of the trap in radial directions before detecting other ions using a detector mounted along the z-axis can significantly increase the operating lifetime of the ion detector, by avoiding saturation of the detector during application of the supplemental signal.
  • the quadrupole trapping field has a DC component, it can have both a high frequency and low frequency cutoff, and will be incapable of trapping ions with frequencies of oscillation below the low frequency cutoff or above the high frequency cutoff.
  • Control circuit 31 generates control signals for controlling fundamental voltage generator 14, filament control circuit 21, and supplemental AC voltage generator 35. Circuit 31 sends control signals to circuits 14, 21, and 35 in response to commands it receives from processor 29, and sends data to processor 29 in response to requests from processor 29.
  • Control circuit 31 preferably includes a digital processor or analog circuit, of the type which can rapidly create and control the frequency-amplitude spectrum of each supplemental voltage signal asserted by supplemental AC voltage generator 35 (or a suitable digital signal processor or analog circuit can be implemented within generator 35).
  • a digital processor suitable for this purpose can be selected from commercially available models. Use of a digital signal processor permits rapid generation of a sequence of supplemental voltage signals having different frequency-amplitude spectra (such as application of a notch-filtered broadband signal during ion storage).
  • a trapping field is established in a trap region (e.g., region 16 of Fig. 1), and ions are formed or introduced in the trapping field and are stably trapped therein.
  • the trapping field is capable of storing ions having m/z ratio within a selected range, corresponding to a trapping range of ion frequencies.
  • a combined field (comprising the trapping field and a supplemental field) is established in the trap region, and at least one parameter of the combined field is changed to excite selected ones of the trapped ions sequentially (such as for detection).
  • the supplemental field is periodically varying, with its frequency being an "off-resonance" frequency which nearly matches (but differs from) a frequency of motion of an ion stably trapped by the trapping field alone.
  • the supplemental field is sometimes denoted herein as an "off-resonance" field.
  • Sequential ion excitation in accordance with the invention (“off-resonance" scanning or excitation) can rapidly eject a sequence of the trapped ions from the trap region (or rapidly excite each ion in such sequence to a degree sufficient for a desired purpose) because the off-resonance field will cause an increase in the trajectory of each ion in the sequence, and because the off-resonance field can have a sufficiently large peak-to-peak amplitude to increase each ion trajectory to a desired magnitude within a desired short time period.
  • trapped ions are sequentially excited by holding the off-resonance field fixed while changing at least one parameter of the trapping field component of the combined field. In other embodiments, trapped ions are sequentially excited by changing (such as scanning) at least one parameter of the off-resonance field while holding the trapping field fixed.
  • the peak-to-peak amplitude of the off-resonance field is kept sufficiently high to excite ions (via an off-resonance excitation mechanism) before they undergo resonant excitation.
  • the peak-to-peak amplitude of the off-resonance field is kept sufficiently high to eject each of a sequence of trapped ions from the combined field via off-resonance excitation, before the secular motion of any ion in the sequence undergoes resonant excitation in the changing combined field.
  • the rate of change of combined field parameters and the peak-to-peak amplitude of the (fixed or changing) supplemental field is controlled to keep it below a value which would cause simultaneous ejection of ions having different (but similar) m/z ratios (i.e., via resonant excitation of an ion having a first m/z ratio with simultaneous off-resonance excitation of a second ion having a second m/z ratio slightly different than the first m/z ratio).
  • the peak-to-peak amplitude of the supplemental field might be controlled to be less than one volt (to avoid interference effects such as that described above), whereas in a corresponding embodiment of the invention (one employing the same trapping field) the supplemental signal producing the off-resonance field could have peak-to-peak amplitude much greater than one volt (to enable mass analysis to be performed much more rapidly than in the conventional resonant excitation).
  • the off-resonance field component of the inventive changing combined field excites a sequence of trapped ions in the following manner.
  • the frequencies of motion of each trapped ion are defined by parameters that map to a point within the stability envelope (in embodiments in which the trapping field is not a quadrupole trapping field, the shape of the stability envelope can differ from that shown in Fig. 2).
  • the off-resonance field component of the changing combined field excites each ion in the sequence (via off-resonance excitation) to increase the ion's trajectory without causing the ion to become unstable. In other words, during off-resonance excitation, the parameters of the ions's motion continue to map to a point within the stability envelope.
  • Each ion is excited to a desired degree within a desired time (via off-resonance excitation) before the point to which the ion maps in the stability envelope matches a resonance point (i.e., before the frequency of ion motion matches the frequency of the applied supplemental AC signal, and thus, before the ion undergoes resonant excitation in the changing combined field).
  • the changing combined field sequentially ejects selected trapped ions from the combined field for detection (or purposes other than detection).
  • the invention sequentially excites trapped ions without ejecting them from the combined field.
  • the combined field is established in the trap region (e.g. region 16 shown in Fig. 1) of a three-dimensional quadrupole ion trap (such as that shown in Fig. 1).
  • the combined field comprises a quadrupole trapping field produced by applying the above-described fundamental voltage to one or more of the ring electrode and end electrodes of the trap, and an off-resonance supplemental field produced by applying a supplemental AC voltage across the end electrodes.
  • the amplitude of an RF (or DC) component of the fundamental voltage can be scanned or otherwise changed while the supplemental AC voltage is applied across the end electrodes, or the quadrupole trapping field can be held fixed while a parameter of the supplemental AC voltage is scanned or otherwise changed, to sequentially excite ions having a range of m/z ratios for detection (or for any of a variety of other purposes, including inducement of ion reaction or dissociation in the presence of a buffer gas).
  • a second supplemental field can be superimposed with the trapping field (before or during superimposition of the off-resonance field with the trapping field) to eject unwanted ions having m/z ratio within a second selected range from the combined field, wherein the second supplemental field has frequency components within a lower frequency range from a first frequency up to a notch frequency band, and within a higher frequency range from the notch frequency band up to second frequency, and wherein the frequency range spanned by the first frequency and the second frequency includes the trapping range.
  • Such second supplemental field can eject ions from the trap region (other than selected ions), thereby preventing storage of undesired ions which might otherwise interfere with subsequent mass spectrometry operations.
  • the second supplemental field has two or more notch frequency bands (i.e., absences of frequency components).
  • the second supplemental field can have frequency components within a low frequency range from a first frequency up to a first notch frequency band, within a middle frequency range from the first notch frequency band to a second notch frequency band, and within a high frequency range from the second notch frequency band up to a second frequency.
  • each of the second supplemental field's frequency components preferably has an amplitude in the range from 10 mV to 10 volts.
  • the combined field can be changed (for example, by changing the frequency of, and switching on the off-resonance field component of the combined field) to induce dissociation of parent or daughter ions, and then changed in a different manner (e.g., by being swept or scanned) to perform mass analysis of daughter ions.
  • the trapping field and off-resonance field can be established by applying voltage signals to ion trap apparatus electrodes which surround the trap region.
  • the trapping field is a quadrupole field determined by a sinusoidal fundamental voltage signal having a DC voltage component (of amplitude U) and an RF voltage component (of amplitude V and frequency ⁇ ) applied to one or more of the ring electrode and end electrodes of a quadrupole ion trap.
  • a buffer or collision gas such as, but not limited to, Helium, Hydrogen, Argon, or Nitrogen
  • a buffer or collision gas such as, but not limited to, Helium, Hydrogen, Argon, or Nitrogen
  • the mass analysis step i.e., during the step of changing the combined field
  • the trapping field component of the combined field is a hexapole (or octopole or higher order multipole) trapping field, which is established by applying a sinusoidal (or other periodic) fundamental voltage to the electrodes of a hexapole (or octopole or higher order multipole) ion trap.

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  • Analytical Chemistry (AREA)
  • Electron Tubes For Measurement (AREA)
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Claims (22)

  1. Massenspektrometrieverfahren mit folgenden Schritten:
    a) Errichten eines Einfangfeldes, das in der Lage ist, Ionen mit einem Massezuladungsverhältnis innerhalb eines ausgewählten Bereichs in einer Einfangregion stabil einzufangen;
    b) Überlagern eines Zusatzfeldes zu dem Einfangfeld, um ein kombiniertes Feld in der Einfangregion zu bilden, wobei das Zusatzfeld ein periodisch sich änderndes Feld mit einer Außerresonanzfrequenz darstellt, welche nahe zu der Frequenz einer Frequenzkomponente des Frequenzspektrums der Oszillation eines durch das Einfangfeld allein stabil eingefangenen Ions gleichkommt; und
    c) Ändern des kombinierten Feldes, um ausgewählte eingefangene Ionen in der Einfangregion zu erregen, um so die Massenanalyse durchzuführen.
  2. Massenspektrometrieverfahren nach Anspruch 1,
    dadurch gekennzeichnet, daß das Einfangfeld ein Quadropoleinfangfeld darstellt, das von der Anlage einer Spannung an mindestens einer Elektrode (11, 12, 13) des Quadropolioneneinfangapparates erhalten wird, worin das Zusatzfeld von der Anlage einer zweiten Spannung an mindestens eine Elektrode des
    Quadropolioneneinfangapparates resultiert und worin ein Parameter in Schritt c) geändert wird, der mindestens die Spannung oder die zweite, an mindestens einer der Elektroden (11, 12, 13) anliegende Spannung betrifft.
  3. Verfahren nach Anspruch 2,
    dadurch gekennzeichnet, daß der Parameter eine Amplitude darstellt, die mindestens die Spannung oder die zweite, an mindestens eine Elektrode (11, 12, 13) angelegte Spannung betrifft.
  4. Verfahren nach Anspruch 2,
    worin der Parameter eine Frequenz darstellt, die mindestens die Spannung und die zweite, an mindestens einer Elektrode (11, 12, 13) angelegte Spannung betrifft.
  5. Verfahren nach einem der Ansprüche 2 bis 4,
    worin die Spannung ein sinusförmiges fundamentales Spannungssignal mit einer
    Hochfrequenzspannungskomponente der Amplitude V und der Frequenz ω darstellt und worin die zweite Spannung ein sinusförmiges zusätzliches Spannungssignal der Amplitude Vsupp und der Frequenz ωsupp darstellt.
  6. Verfahren nach Anspruch 5,
    worin das sinusförmige fundamentale Spannungssignal noch eine Gleichstromspannungskompnente aufweist.
  7. Verfahren nach Anspruch 2,
    worin der Schritt c) die Steuerung einer Änderungsrate mindestens eines Parameters des kombinierten Feldes umfaßt, um eine erwünschte Massenauflösung zu erzielen.
  8. Massenspektrometrieverfahren nach Anspruch 1 oder 2, mit folgenden weiteren Schritten:
    d) ein zweites zusätzliches Feld wird mit mindestens dem Einfangfeld oder dem kombinierten Feld überlagert, wobei das zweite zusätzliche Feld ein Frequenzspektrum aufweist, das mindestens eine Nut bei einem vorgewählten Frequenzband umfaßt.
  9. Massenspektrometrieverfahren nach Anspruch 1 oder 2, worin während des Schrittes c) das zusätzliche Feld des kombinierten Feldes eine genügend große Spitze zu Spitze Amplitude aufweist, so daß das kombinierte Feld eine Bahn der jeweilig erwünschten, eingefangenen Ionen auf eine gewünschte Größe innerhalb einer erwünschten Zeitperiode bringt.
  10. Massenspektrometrieverfahren nach Anspruch 1 oder 2, mit folgendem weiterem Schritt:
    e) mindestens ein Kollisionsgas oder ein Puffergas wird in die Einfangregion eingeführt, um mindestens die Massenauflösung oder die Sensibilität zu verbessern.
  11. Massenspektrometrieverfahren nach Anspruch 1 oder 2,
    dadurch gekennzeichnet, daß der Schritt c) mindestens ein Parameter des kombinierten Feldes umfaßt, um aufeinanderfolgend ausgewählte eingefangene Ionen in dem Einfangbereich zu erregen, das zusätzliche Feld eine Spitze zu Spitze Amplitude aufweist und daß das zusätzliche Feld im wesentlichen festgehalten wird während mindestens ein Parameter des Einfangfeldes abgetastet wird und die Spitze zu Spitze Amplitude des zusätzlichen Feldes genügend hoch gehalten wird, so daß das kombinierte Feld die ausgewählten gefangenen Ionen in Folge eines Außerresonanzerregungsmechanismus nacheinander erregt, bevor die ausgewählten gefangenen Ionen der resonanten Erregung unterliegen.
  12. Verfahren nach Anspruch 11,
    dadurch gekennzeichnet, daß das Einfangfeld ein Quadropoleinfangfeld ist, das durch Anlage einer fundamentalen Spannung an mindestens eine Elektrode (11, 12, 13) des Quadropolioneneinfanggeräts erzeugt wird und daß der Schritt c) die Abtastung einer Amplitude einer Komponente der fundamentalen Spannung umfaßt.
  13. Verfahren nach Anspruch 11,
    dadurch gekennzeichnet, daß das Einfangfeld ein Quadropoleinfangfeld darstellt, welches durch Anlage einer fundamentalen Spannung an mindestens eine Elektrode (11, 12, 13) eines Quadropolioneneinfanggeräts erzeugt wird und daß Schritt c) die Abtastung einer Frequenz der fundamentalen Spannung umfaßt.
  14. Massenspektrometrieverfahren nach Anspruch 1 oder 2,
    dadurch gekennzeichnet, daß der Schritt c) die Abtastung von mindestens einem Parameter des kombinierten Feldes umfaßt, um ausgewählte eingefangene Ionen in der Einfangregion nacheinander zu erregen, während das zusätzliche Feld eine Spitze-zu-Spitze-Amplitude aufweist und daß mindestens ein Parameter des zusätzlichen Feldes angetastet wird, während das Einfangfeld im wesentlichen bei einem festen Wert gehalten wird und die Spitze-zu-Spitze-Amplitude des zusätzlichen Feldes genügend hoch gehalten wird, so daß das kombinierte Feld die ausgewählten eingefangenen Ionen infolge eines Außerresonanzerregungsmechanismus nacheinander erregt, bevor die ausgewählten eingefangenen Ionen der Resonanzerregung unterliegen.
  15. Verfahren nach Anspruch 14,
    dadurch gekennzeichnet, daß das zusätzliche Feld durch Anlage einer zusätzlichen Wechselspannung an mindestens eine Elektrode eines Quadropolioneneinfanggeräts erzeugt wird und daß Schritt c) die Abtastung einer Amplitude einer Komponente der zusätzlichen Wechseispannung umfaßt.
  16. Verfahren nach Anspruch 14,
    dadurch gekennzeichnet, daß das zusätzliche Feld durch Anlage einer zusätzlichen Wechselspannung an mindestens eine Elektrode eines Quadropolioneneinfanggeräts erzeugt wird und daß Schritt c) die Abtastung einer Frequenz der zusätzlichen Wechselspannung umfaßt.
  17. Massenspektrometrieverfahren nach Anspruch 1 oder 2,
    dadurch gekennzeichnet, daß der Schritt c) durch Abtastung von mindestens einem Parameter des kombinierten Feldes ausgeführt wird, um ausgewählte eingefangene Ionen in der Anfangregion nacheinander zu erregen, und daß Schritt d) die Überlagerung eines zweiten zusätzlichen Feldes zu mindestens dem Einfangfeld oder dem kombinierten Feld umfaßt, wobei das zweite zusätzliche Feld ein Frequenzspektrum aufweist, welches mindestens eine Nut bei einem ausgewählten Frequenzband aufweist.
  18. Massenspektrometrieverfahren nach Anspruch 1 oder 2,
    dadurch gekennzeichnet, daß der Schritt c) durch Abtastung mindestens eines Parameters des kombinierten Feldes ausgeführt wird, um ausgewählte eingefangene Ionen in der Einfangregion sequentiell oder nacheinander zu erregen und daß das zusätzliche Feld des kombinierten Feldes eine genügend große Spitze-zu-Spitze-Amplitude aufweist, so daß das kombinierte Feld eine Bahn der jeweiligen ausgewählten eingefangenen Ionen auf eine gewünschte Größe innerhalb einer gewünschten Zeitperiode bringt.
  19. Massenspektrometrieverfahren nach Anspruch 1 oder 2,
    dadurch gekennzeichnet, daß der Schritt c) durch Abtastung von mindestens einem Parameter des kombinierten Feldes ausgeführt wird, um ausgewählte eingefangene Ionen in dem Einfangbereich nacheinander zu erregen, und daß Schritt d) die Einführung von mindestens einem Kollisionsgas oder einem Puffergas in den Einfangbereich beinhaltet, um mindestens die Massenauflösung oder die Sensibilität zu verbessern.
  20. Verfahren nach Anspruch 2,
    worin Schritt c) die Änderung des kombinierten Feldes umfaßt, um ausgewählte eingefangene Ionen zur Detektion nacheinander zu erregen.
  21. Verfahren nach Anspruch 2,
    worin Schritt c) die Änderung des kombinierten Feldes umfaßt, um ausgewählte eingefangene Ionen aufeinanderfolgend zu erregen, um diese aus dem Einfangbereich auszuwerfen.
  22. Verfahren nach Anspruch 2,
    worin Schritt c) die Änderung des kombinierten Feldes umfaßt, um ausgewählte eingefangene Ionen aufeinanderfolgend zu erregen, um diese aus der Einfangregion auszuwerfen und durch einen außerhalb der Einfangregion gelegenen Detektor nachzuweisen.
EP94920813A 1993-06-28 1994-06-27 Quadrupol mit einem von der resonanzfrequenz abweichenden angelegten signal Expired - Lifetime EP0765190B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US8397293A 1993-06-28 1993-06-28
PCT/US1994/007176 WO1995000237A1 (en) 1993-06-28 1994-06-27 Quadrupole with applied signal having off-resonance frequency
US83972 2002-02-27

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EP0765190A1 EP0765190A1 (de) 1997-04-02
EP0765190A4 EP0765190A4 (de) 1997-09-03
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US5726448A (en) * 1996-08-09 1998-03-10 California Institute Of Technology Rotating field mass and velocity analyzer
US6130980A (en) 1997-05-06 2000-10-10 Dsm N.V. Ribbon assemblies and ink coating compositions for use in forming the ribbon assemblies
US6197422B1 (en) 1997-05-06 2001-03-06 Dsm, N.V. Ribbon assemblies and radiation-curable ink compositions for use in forming the ribbon assemblies
EP1463090B1 (de) * 2001-11-07 2012-02-15 Hitachi High-Technologies Corporation Massenspektrometrie und ionenfallenmassenspektrometer
US6794647B2 (en) 2003-02-25 2004-09-21 Beckman Coulter, Inc. Mass analyzer having improved mass filter and ion detection arrangement
US7186972B2 (en) 2003-10-23 2007-03-06 Beckman Coulter, Inc. Time of flight mass analyzer having improved mass resolution and method of operating same
EP2797105B1 (de) * 2013-04-26 2018-08-15 Amsterdam Scientific Instruments Holding B.V. Detektion von Ionen in einer Ionenfalle

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US4982088A (en) * 1990-02-02 1991-01-01 California Institute Of Technology Method and apparatus for highly sensitive spectroscopy of trapped ions
US5182451A (en) * 1991-04-30 1993-01-26 Finnigan Corporation Method of operating an ion trap mass spectrometer in a high resolution mode

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DE69422429D1 (de) 2000-02-03
CA2166207A1 (en) 1995-01-05
EP0765190A1 (de) 1997-04-02
JP3067208B2 (ja) 2000-07-17
DE69422429T2 (de) 2000-08-03
JPH09501537A (ja) 1997-02-10
CA2166207C (en) 2003-09-16
EP0765190A4 (de) 1997-09-03
ATE188139T1 (de) 2000-01-15
WO1995000237A1 (en) 1995-01-05

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