EP3243210A1 - Verfahren und vorrichtung zur chemischen ionisation eines gasgemisches - Google Patents
Verfahren und vorrichtung zur chemischen ionisation eines gasgemischesInfo
- Publication number
- EP3243210A1 EP3243210A1 EP16709715.3A EP16709715A EP3243210A1 EP 3243210 A1 EP3243210 A1 EP 3243210A1 EP 16709715 A EP16709715 A EP 16709715A EP 3243210 A1 EP3243210 A1 EP 3243210A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- electrodes
- ions
- reaction volume
- central line
- gas
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/0027—Methods for using particle spectrometers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/62—Detectors specially adapted therefor
- G01N30/72—Mass spectrometers
- G01N30/7206—Mass spectrometers interfaced to gas chromatograph
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/06—Electron- or ion-optical arrangements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/10—Ion sources; Ion guns
- H01J49/14—Ion sources; Ion guns using particle bombardment, e.g. ionisation chambers
- H01J49/145—Ion sources; Ion guns using particle bombardment, e.g. ionisation chambers using chemical ionisation
Definitions
- the present invention relates to a method and a device for chemical ionization [CI] of a gas mixture or sample gas, for example by means of ion-atomic reactions or ion-molecule reactions [IMR], in particular by means of proton exchange reactions [PTR].
- the gas mixture consists of at least one main component or a carrier gas (eg O 2 , N 2 or a mixture thereof, eg air) and one or more reactant gases or analytes (eg volatile organic compounds [VOCs]).
- a carrier gas eg O 2 , N 2 or a mixture thereof, eg air
- reactant gases or analytes eg volatile organic compounds [VOCs]
- the ionization extends such that by reaction with additionally introduced into the gas mixture IonPrimär- primary ions (for example, H 3 0 +, NH 3 +, NO +, 0 + 2, N0 3 ⁇ ) of non-ionized atoms or molecules of the reactant gases product Ions are formed.
- IonPrimär- primary ions for example, H 3 0 +, NH 3 +, NO +, 0 + 2, N0 3 ⁇
- the reactant gases are usually present in very small concentrations, typically in the ppbv to pptv range (ie parts per billion / trillion by volume).
- the invention further relates to the use of the method according to the invention and / or the device according to the invention in methods and / or devices for analyzing the properties of a gas mixture or sample gas, in particular for analysis by means of CI mass spectrometers, in particular by means of IMR and PTR mass spectrometers.
- a gas mixture or sample gas which consists of a main component or a carrier gas (eg 0 2 , N 2 or a mixture thereof, eg air) and one or more (usually in very small concentrations existing) reactant gases or analytes (eg volatile organic compounds [VOCs])
- the chemical ionization [CI] of particles (ie atoms or molecules) of the reactant gases by introducing into the sample gas primary ions and by reactions between the primary ions and the reactant gas particles from the previously neutral reactant gas particles so-called product ions are formed, these ionizing reactions also from can consist of several reaction steps.
- the ionization of particles of the carrier gas is usually not intended here.
- the product ions and the remaining primary ions are either immediately supplied to an ion-selective analyzer / detector unit (eg a mass spectrometer or an ion mobility spectrometer) or further process steps.
- an ion-selective analyzer / detector unit eg a mass spectrometer or an ion mobility spectrometer
- a special form (ie a subgroup) of chemical ionization processes are the so-called proton exchange reactions [PTR].
- PTR proton exchange reactions
- the ionization of a reactant gas particle R takes place by transfer of a proton H + of a primary ion XH + , whereby a product ion RH + is formed and the primary ion XH + becomes a neutral molecule X:
- Chemical ionization processes are "gentle" in the sense that less energy is transferred to the resulting product ion than many other ionization processes (eg electron impact ionization) .Cl processes are therefore particularly advantageous for the ionization of molecules, their product Thus, Cl processes are particularly advantageous for applications where the sample gas to be ionized contains molecules whose product ions are likely to fragment (eg, VOCs), but which are undesirable for fragmentation is.
- CI mass spectrometry in particular analytical CI mass spectrometry, ie not only the masses or the type of analyte gas particles contained in the sample gas are determined in the analysis of the sample gas but also the concentrations of the analyte gas particles are to be measured quantitatively either absolutely or relative to each other.
- CI mass spectrometry is now a very sophisticated technical field, which is why it has the richest state of the art regarding methods and devices for the ionization of a sample gas by means of chemical ionization [CI].
- CI chemical ionization
- other applications of CI processes are also known and conceivable, e.g. the ion mobility spectrometry.
- the application of the present invention in such other applications is included in the invention, although these further applications will not be discussed further below.
- CI mass spectrometers include the following devices or assemblies: i. A primary ion source in which the primary ions are generated and optionally selected so that only ions of the desired type are present at the output of the primary ion source. ii.
- reaction chamber in which the (in the following "reaction volume” or “reaction area” called) spatial area is located, in which the primary ions interact with the sample gas and thus the product ions are generated
- Reaction chamber designed so that the primary and product ions therein - also by means of electric fields - are also transported and / or guided and / or focused iii)
- a mass spectrometer the product ions generated in the reaction chamber and usually also the remaining Primary ions are supplied to determine their masses, and preferably also their (relative) concentration
- the most common types today are quadrupole mass spectrometers [Quad-MS] and time-of-flight mass spectrometers [TOF-MS].
- further separate assemblies for transferring the ions from one assembly to the next eg for accelerating, guiding or focusing the ion
- acceleration sections e.g. acceleration sections, ion guides, ion lenses or ion funnels.
- Other required for the operation of components and assemblies such as valves, pumps, power supplies, especially for example for the application of voltages to electrodes, etc.
- the PTR mass spectrometry and generally the CI mass spectrometry are described, for example, in Ref. IM, AT 001637 Ul (Lindinger & Hansel) and in the references cited therein. Further descriptions of PTR mass spectrometry can be found, inter alia. in Ref. / 2 /, A. Hansel et al, International Journal of Mass Spectrometry and Ion Processes, 149/150 (1995) 609-619 and Ref. / ⁇ /, A. Jordan et al., International Journal of Mass Spectrometry, Vol. 286 (2009) 32-38.
- reaction chamber the assembly ii)
- process chamber the assembly ii)
- process steps taking place in this reaction chamber The relevant patent and technical literature contains several different names for this reaction chamber, such as “reaction or ionization range”. , “Reaction or ionization cell”, or in those cases where the primary and product ions drifted by electric fields driven by the sample gas, also "drift tube or region”.
- SIFT selected ion flow tube
- the primary and product ions are transported to the outlet of the reaction chamber solely by the sample gas flow
- a disadvantage of this embodiment is, on the one hand, that ions diffuse unhindered towards the chamber wall on their way towards the outlet of the reaction chamber and there Furthermore, it is disadvantageous that in the presence of, for example, water vapor in the sample gas, clustering of the primary ions with water molecules occurs, and the CI process with the clustered primary ions
- the analyte C 6 H 6 (benzene) is ionized by the primary ion H 3 0 + , but not by the primary ion cluster H 3 0 + H 2 0.
- reaction chambers formed as so-called drift pans, such as e.g. Ref. / 2 /, A. Hansel et al. cited above. (1995).
- the reaction chamber has a plurality of coaxial annular electrodes spaced along an axis. These annular electrodes surround the reaction volume of the reaction chamber, within which the primary ions react with the sample gas and produce product ions.
- a DC voltage is applied to the ring electrodes, wherein in each case a potential difference is present between adjacent ring electrodes, which accelerates the ions axially towards the exit of the reaction chamber.
- drift tubes operated with axial DC fields Another disadvantage of such drift tubes operated with axial DC fields is that the ions are not guided transversely to the axis or not focused towards the axis, therefore freely diffuse away from the axis and therefore only a fraction of the ions passes through the exit aperture of the reaction chamber , which in turn reduces the product ion yield.
- One possibility for guiding the ions in this annular electrode topology also transversely to the axis or to focus on the axis is to apply to the ring electrodes in addition to the DC voltage also AC voltages, such. Barber et al., Analytical Chemistry, Vol. 84, 5387-5391, or Ref.
- RF alternating voltages i.e., AC voltages in the radio frequency range of about 100 kHz to about 100 MHz
- These RF AC voltages produce an effective potential that focuses the ions toward the axis, thus preventing ions from diffusing to the chamber wall or electrodes and being lost or neutralized there.
- DC voltages can be additionally superimposed to transport the ions towards the exit of the reaction chamber.
- a disadvantage of such ring-shaped electrodes and operated with RF alternating voltages so-called ionic lenses and ion funnels is in particular that the impact energies of the ions vary greatly in time and locally, since on the one hand the RF field oscillates at each point by the value zero and on the other hand the amplitude of this oscillation varies greatly along the axis.
- the setting of an optimum in terms of avoiding clustering and fragmentation average impact energy - which ideally should be as constant as possible in the entire reaction volume temporally and locally - is made impossible.
- Another known possibility to guide the ions in the reaction chamber transversely to their transport direction or to focus on the axis is to Use quadrupoles, hexapoles, octopoles, etc. for ion guidance.
- an RF alternating voltage is applied to an even number of parallel to the axis symmetrically arranged around the reaction chamber rod electrodes, which is phase-shifted between two adjacent rod electrodes in each case by 180 ° and phase-shifted between two opposing rod electrodes by 0 °.
- Such arrangements hereafter referred to as "2-phase multipoles" - produce an effective potential that focuses the ions toward the axis, and this effective potential arises from the interplay of the oscillating RF field with the random collisions of the ions with the one Buffer gas acting neutral particles of the carrier gas.
- a disadvantage of such 2-phase multipoles is the fact that the electric field is always zero volts per centimeter [V / cm] on the axis, since here the fields of the respectively opposite rod electrodes cancel each other out. This means that with the fields generated by such 2-phase multipoles, the average impact energy of the ions near the axis, that is, at the location where most ions are due to focusing, is not increased, thus undesirable clustering does not occur can be reduced.
- the magnitude of the electric field vector oscillates between zero V / cm and a maximum value Emax (r), which depends on the radial distance r from the axis. This leads to the same problem as already described above: The setting of an optimum in terms of avoiding clustering and fragmentation average impact energy is thereby made impossible.
- EP 1 566 829 A2 (Hansel [AT], Wisthaler [AT]), 2005-08-24
- the object of the invention is to provide a method and a device of the type mentioned, which improve the above-described disadvantages of the prior art, in particular by the product ion yield is improved by a better reduction of unwanted clustering on the one hand and unwanted fragmentation on the other hand. This object is achieved with the features of the claims.
- the present invention is concerned with the improvement of methods and apparatus for chemical ionization [CI] of a gas mixture or sample gas, said gas mixture consisting of at least one main component or a carrier gas and one or more present in very small concentrations of reactant gases or analytes ,
- the said ionization process takes place in such a way that product ions are formed by reactions with primary ions additionally introduced into the gas mixture from non-ionized atoms or molecules of the reactant gases.
- the surface of this reaction volume (1) consists of a first cover surface (2), a second cover surface (3) and a lateral surface (4) extending between these two cover surfaces.
- the reaction volume is penetrated by an axis (hereinafter referred to as center line (5)) which extends from the first cover surface (2) to the second cover surface (3) and runs entirely within the reaction volume (1), so that at each location in the reaction volume (1) an axial direction is defined, which is parallel to the central line (5) and a radial direction and a radial plane are defined, which are perpendicular to the central line (5).
- center line (5) an axis
- reaction volume (1) first cover surface (2), second cover surface (3), lateral surface (4) and center line (5) do not mean actually existing components of a device, but (abstract) geometric objects for describing topological properties of the prior art and the present invention.
- the reaction volume (1) is substantially rotationally symmetric, e.g. Cylindrical or conical.
- the center line (5) lies here on the straight rotational symmetry axis of the cylinder.
- Other, different from the rotationally symmetric shape of the reaction volume variations are possible, sometimes advantageous and provided according to the invention, such. those having a bow-shaped or S-shaped central line, for example, to block out undesired radiation emerging from the primary ion source as it passes through the reaction space and to prevent it from entering the reaction chamber (e.g., mass spectrometer).
- This prior art topology of the reaction volume (1) results from the fact that the primary ions are mostly introduced through the first cover surface (2) into the reaction volume (1) and the Product ions (and also the remaining primary ions) by means of a gas flow and / or by means of static electric fields in the axial direction through the reaction volume are transported until they leave the reaction volume through the second top surface (3) towards the exit of the reaction chamber.
- focusing the ions on the central line (5), ie a radial guiding is advantageous and desirable, but not absolutely necessary.
- the axial direction is thus the transport or drift direction of the ions, and the radial direction perpendicular thereto is that in which the ions are optionally guided by means of effective potentials generated by RF fields or to the center line (5). be focused.
- the invention provides a method of the type mentioned above, which improves the disadvantages of the prior art, in particular by better fulfilling the above optimization criteria than the prior art. This is achieved according to the invention by the characterizing features of claims 1 to 5.
- the method according to the invention can furthermore comprise the following method steps: Step A): Accelerating the ions (primary ions, product ions formed and possibly formed ion clusters) present in the reaction volume (1) by means of a temporally periodic electric field E (x, t) .
- E (x, i) has, at all points (Z) located on the central line (5), a rectangular (ie radial) field vector component E r (Z) which rotates periodically, ie, during rotation Period exactly T performs a 360 ° rotation in the radial plane and the amount
- t is the time x is a position vector, for example with the Cartesian coordinates (x, y, z)
- Z is the position vector of a point located on the center line (5)
- ⁇ Z ⁇ is the set of all belonging to the center line (5)
- Is position vectors Z and T is the period of a 360 ° rotation of ⁇ , ( ⁇ , ⁇ )
- a temporally periodic electric field E (x, i) is applied which has the following property at all points ⁇ Z ⁇ of the central line:
- the field vector E (Z, t) has no significant axial component, therefore, is perpendicular to the central line, rotates periodically and has a nearly constant or preferably constant amount E 0 .
- the ions are not driven radially out of the reaction volume in the direction of the lateral surface, which would violate criterion D) [duration of residence or reaction time], but on the contrary: in interaction with randomizing collisions of the ions with the Like a neutral gas carrier gas acting as a buffer gas, the rapidly rotating, spatially inhomogeneous E field generates an effective potential that focuses the ions towards the center line, which also satisfies the optimization criterion E) [focusing].
- a periodically rotating radial component E, (Z, t) supplies kinetic energy to the ion ensemble, which serves to avoid clustering without thereby accelerating the transport of the ions through the reaction volume and thereby unfavorably shortening the reaction time ,
- E-fields according to the invention can also be generated with phase-shifted rectangular voltages.
- the preferred frequencies are in the MHz range, and the necessary electrical voltages reach into the kV range.
- an ideal square-wave signal is not feasible, and it may therefore happen in the generation of the inventive E-field that the rotating field vector E, (Z, /) also becomes zero at some times during one revolution, due to a from the perfect rectangle deviating signal shape. In those (majority) times when E r (Z, not zero, it unfolds the above-described inventive and advantageous effect.
- the applied E-field also has an axial component E axj (Z, t), preferably with a moderate, but constant amount.
- This axial component can be used to transport the ions to the exit of the reaction volume, if no corresponding gas flow takes place. Conversely, with strong gas flow, this axial component can be used to advantageously extend the residence time of the ions in the reaction volume by directing this axial component against the gas flow.
- E-fields in which the amount
- E-fields which are characterized in that the rotation of the radial field vector component ⁇ , ( ⁇ , ⁇ ) substantially corresponds to a harmonic circular motion, i. that ⁇ , ( ⁇ , ⁇ ) is represented in Cartesian coordinates (X, Y) which are perpendicular to the center line (5) at the respective point Z, satisfying the following equation:
- E ⁇ Z u x - [A x (Z, - sin (cuet + ⁇ I> 0)] + u y - [ ⁇ ⁇ ( ⁇ , 'cos (cot + ⁇ 0)],
- u x is the unit vector of the x-coordinate and u y is the unit vector of the y-coordinate, ⁇ is the angular frequency of the rotation, ⁇ 0 is a global phase offset, and
- varies by a maximum of ⁇ 10%, preferably constant at all times, ie
- E 0 ⁇ 10%.
- E 0 is a constant (claim 4).
- E-fields are particularly preferred and advantageous, which are characterized in that the magnitude
- the invention provides a device of the type mentioned, which improves the disadvantages of the prior art, in particular by providing a device which, for example, also allows the implementation of the inventive advantageous method.
- the invention enables the generation of electric fields E (x, t) with the characterizing features of the method claims 1 to 5 in the reaction volume. This is achieved according to the invention in particular by the characterizing features of claims 6 to 14.
- Said device includes - like most chemical ionization reaction chambers in the prior art - a reaction area or a reaction volume (1), wherein the surface of this reaction volume from a first top surface (2), a second cover surface (3) and between the two cover surfaces (2, 3) extending lateral surface (4) and the reaction volume (1) is penetrated by a central line (5) extending from the first top surface (2) to the second top surface (3) and extends entirely within the reaction volume (1), so that in the reaction volume (1) an axial direction is defined, which is parallel to the central line (5) and a radial direction and a radial plane are defined, perpendicular to the central line (5) stand.
- reaction volume (1) first top surface (2), second top surface (3), lateral surface (4) and central line (5) not really existing components of a device are meant, but (abstract) geometric Objects describing topological properties of the prior art and the present invention.
- Said device further comprises at least three or more preferably rod-shaped electrodes (6), i. N electrodes (6), where N is an integer greater than or equal to three, each of these N> 3 electrodes (6) being formed and arranged to extend from the edge of the first top surface (2) to the edge of the second top surface (3) extends and from the outside to the reaction volume (1) nestles, that is, that it touches the lateral surface (4) tangentially from the outside in its entire extension course.
- Said device further comprises an AC voltage source, which is electrically connectable to each of the N> 3 electrodes (6),
- Said device is characterized in that the AC voltage source is designed so that each of the N> 3 electrodes (6) in each case a periodic alternating voltage (ie a time-periodic voltage) Uj (t) can be applied, wherein Uj (?) The AC voltage at the ith electrode,
- phase positions ⁇ when numbering the electrodes (6) along the edge of a top surface (2, 3) in one direction (i.e., in a sense of rotation), the phase positions ⁇ ; or ascending order, i.
- Ati 0 ⁇ At 2 ⁇ ... ⁇ Ah ⁇ ... ⁇ At- N ⁇ T.
- at least three electrodes extend from the edge of the first cover surface (2) along the lateral surface (4) to the edge of the second cover surface (3) and are subjected to alternating voltages that have in a sense of rotation rising phase positions. This makes it possible to generate a periodically rotating electric field in the reaction volume, which has the characteristic features of the electric field of the method according to the invention, and consequently effects the advantages described in detail above.
- the device according to the invention is referred to by the term "N-phase multipole", ie, for example, in the case of three electrodes with “N-phase tripole".
- N-phase multipole ie, for example, in the case of three electrodes with "N-phase tripole".
- the electrodes are driven only with two phase positions (0 ° and 180 °), and therefore do not produce a rotating E-field and further where the E-field on the center line is always zero, are termed the "2-phase multipole".
- Fig. 1 shows a rough schematic oblique view of an embodiment of the device according to the invention with four symmetrically arranged electrodes
- FIG. 2a-c show rough-schematic sections through an N-phase tripol according to the invention (FIG. 2a) and an N-phase quadrupole (FIGS. 2b and 2c) and in each case the time profile of the rotating E-field vector E r (FIG. Z, t) -
- FIG. 3 shows, roughly schematically, the qualitative course of the average impact energy between primary ions and neutral carrier gas particles on the center line as a function of time within a period T for an RF ion funnel with and without superposed DC DC voltage, for a second
- Phase-Qadrupol ( prior art) and for an N-phase multipole invention.
- FIGS. 4a-h show schematic oblique views of exemplary embodiments of the electrodes (6) according to the invention.
- Fig. 5 shows a rough schematic of a section through an N-phase quadrupole according to the invention, which is driven with phase-shifted rectangular voltages with the duty cycle 1: 4. Shown are also roughly schematic the voltage applied to the electrodes (6) rectangular voltages and the E-field vector
- FIG. 1 shows a rough schematic oblique view of an embodiment of the device according to the invention with four symmetrically arranged electrodes (6), which are controlled with four sine voltages Uj (t) with the phase positions 0 90 ° / 180 ° / 270 °. Shown are the electrodes (6), and the reaction volume (1) with the two top surfaces (2, 3), the lateral surface (4) and the center line (5). The AC voltage source and the electrical connections to the electrodes are not shown in FIG. 1 for the sake of clarity.
- the central line (5) is here bent S-shaped, and the cross section through the reaction volume (1) is circular in the entire course of the central line (5) with a constant radius.
- FIG. 1 It can clearly be seen in FIG. 1 that the four electrodes (6) are driven according to the invention with alternating voltages whose phase position is ascending in a direction of rotation.
- the turning direction shown here is the counterclockwise direction.
- FIG. 2a-c show roughly schematic sections through an N-phase tripole according to the invention (FIG. 2a) and an N-phase quadrupole (FIGS. 2b and 2c) and in each case the time profile of the rotating E-field vector ⁇ circumflex over () ⁇ , ⁇ suppliess Schweizer, ⁇ Reference numerals have been omitted in this figure for the sake of clarity, since it is clear that they are cuts through the electrodes (6), in which the alternating voltages U; (t) are applied.
- FIG. 2 a shows the situation with an N-phase tripole according to the invention: If this symmetrical electrode arrangement is driven with three sine voltages of the phase positions 0 °, 120 ° and 240 °, the E-field vector E, - ( Z, on the center line (5) is a harmonic circular motion with constant magnitude and constant angular velocity The scheme of the E field vector E r (Z, t) is shown in a rough schematic assuming that sinusoidal voltages of 1 MHz are applied.
- FIG. 2b shows the same as FIG. 2a, but here for an N-phase quadrupole according to the invention, that is to say an embodiment with four electrodes against which sinusoidal voltages with the phase positions 0 °, 90 °, 180 ° and 270 ° are applied.
- Fig. 2c shows the same as Fig. 2b, but here the time course of the E field vector E r (x, /) is shown at a point x off the central line. It can clearly be seen that the field vector rotates periodically, that its magnitude never becomes zero, and that its magnitude changes only moderately during a rotation.
- the ionic funnel on which FIG. 3 is based are, as described above in the "prior art" section, in the form of axially arranged ring electrodes which are alternately acted upon by alternating RF voltages of 0 ° and 180 ° and optionally with DC direct voltages, and so on
- RF voltages 0 ° and 180 °
- DC direct voltages DC direct voltages
- FIGS. 4a-h show oblique views of exemplary embodiments of the electrodes (6) according to the invention. For reasons of clarity, only the electrodes and the center line (5) (dashed line) are shown, but not the surface of the reaction volume (1).
- FIGS. 4e-h show exemplary embodiments with helically shaped electrodes (6). These embodiments produce an effective potential in the axial direction with a gas mixture of ions plus neutral carrier gas particles.
- This effective axial potential can be advantageously used for moderately transporting the ions through the reaction volume.
- the direction of this effective axial potential in the case of heated electrodes depends on the direction of rotation of the applied alternating voltages. Therefore, this effective potential can also be used to brake the ions against the sample gas flow to keep them longer in the reaction volume.
- a (moderate) field component E ax j (Z) is generated, which can also be constant over time, and thus provides an axial DC contribution, which is advantageous for moderately transporting the ions through the Reaction volume or for braking against the sample gas flow can be used.
- tapered electrode configurations are advantageously used to focus the ions on an output aperture.
- Fig. 4c and g show embodiments with S-shaped bent central line, the advantages of which have already been mentioned in detail above. Of course, other advantageous forms of the central line, as S-shaped conceivable and provided according to the invention.
- FIGS. 4d and h show a special case of a reaction volume according to the invention:
- the first cover surface and the second cover surface coincide in one surface and the reaction volume is self-contained, with which the ions can be kept in the reaction volume for a very long time.
- suitable additional devices would then have to be provided for introducing and removing the gas particles.
- electrode shapes other than those shown in Fig. 4 are also possible and provided according to the invention, e.g. Helices with varying pitch or other freeforms extending from the edge of the first deck surface (2) to the edge of the second deck surface (3) and tangent to the lateral surface (4) nestle.
- Fig. 5 shows a rough schematic of a section through an N-phase quadrupole according to the invention, which is driven with phase-shifted rectangular voltages with the duty cycle 1: 4. Shown are also roughly schematic the voltage applied to the electrodes (6) rectangular voltages and the E-field vector E r (Z, t) at the four times tj to t 4 . It can be clearly seen in FIG. 5: at time t.sub.i there is only a voltage at the first electrode, therefore the E-field vector at this time points to the first electrode. At time t 2 , a voltage is applied only to the second electrode, therefore, the E-field vector at this time points to the second electrode, and so on.
- the E-field vector thus rotates quasi “hopping” in 90 ° increments, its magnitude is general but it can be shown in general that at the following duty cycles the amount of the "hopping" rotating E-field vector remains constant: the duty cycle Q of the square-wave voltage must satisfy the following equation:
- N the number of electrodes and n is an integer between 1 and (1-N).
- the preferred frequencies are in the MHz range and the preferred voltages are in the kilovolt range.
- perfect square wave voltages are not technically feasible because of the limited cutoff frequency and slew rate of real AC sources.
- the period T can be kept short, the advantages of the invention remain naturally obtained, because the ions can be accelerated at least for the most part with the optimum field strength.
- Circular cross sections are e.g. particularly preferred for optimizing the magnitude constancy of the rotating E-field on the center line (5).
- Hyperbola segments with rounded edges in particular for optimizing the homogeneity of the E field and / or the effective potential in the entire reaction volume (1)
- cross-sections that taper in the extension of the electrodes are provided and advantageous according to the invention, in particular with tapered reaction volume.
- the following process parameters are particularly preferred in the case of the chemical ionization carried out according to the invention:
- Emax about 500 V / cm to about 10 kV / cm
- sinusoidal and rectangular alternating voltages are particularly preferred.
- different waveforms are advantageous for some applications and provided according to the invention, such as: Triangular or sawtooth voltages, for example for the purpose of widening the impact energy of the accelerated ion ensemble from the field.
- DC offset in particular also those that change along the electrodes (6) by the electrodes are made segmented or are made of a resistive material. Thereby, e.g. an axially acting E-field component for transporting the ions towards the exit of the reaction chamber can be implemented.
- modulated AC voltages e.g. for improving the effective potential focusing on the center line (5).
- the performance of the invention has been tested experimentally using a first prototype in the following way: With a state-of-the-art PTR mass spectrometer (IONICON ® PTR-TOF 8000) was converted to shipped by the manufacturer Protonenley- reaction chamber of an inventive reaction chamber, and comparative measurements were carried out with identical sample gas mixtures in both variants. H 3 O + ions were used as primary ions, and the process parameters gas pressure, electric field strength, and temperature were optimized for each of the two variants in longer series of experiments.
- the manufacturer-supplied reaction chamber is designed as a standard drift tube with ring electrodes to which DC voltages are applied. The axial length of the cylindrical reaction volume in this standard drift tube is 10 cm.
- the prototype type of the reaction chamber according to the invention is designed as a 3-phase tripol.
- the length of the likewise cylindrical reaction volume is 7 cm.
- Phase-shifted RF sinusoidal voltages having a frequency of 10 MHz and an amplitude of 200 volts were applied to the three electrodes according to the invention.
- Table 1 shows the experimental results.
- Four different analyte gases were measured in the carrier gas air with a relative humidity of approx. 60% at 20 ° Celsius.
- a drastic increase in the sensitivity of the spectrometer could be achieved, which is due to the improved product ion yield and the optimal reduction of H 3 0 + H 2 0 clustering is due.
- Columns 2 and 3 show the sensitivities with standard drift tube and 3-phase tripole according to the invention in counts per second per parts per billion by volume [cps / ppbv].
- Column 4 shows the factor by which the sensitivity could be increased by the prototype.
- Column 5 shows this factor extrapolated under the annotation that the reaction volume according to the invention has the same axial length as the standard drift tube. (In realiter, the axial length of the reaction volume for the reaction time of the ions and thus also for the product ion yield or sensitivity was 10 cm for the standard drift tube, but prototypes were only 7 cm).
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Abstract
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Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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EP15156526.4A EP3062332A1 (de) | 2015-02-25 | 2015-02-25 | Verfahren und Vorrichtung zur chemischen Ionisation eines Gasgemisches |
PCT/EP2016/053833 WO2016135179A1 (de) | 2015-02-25 | 2016-02-24 | Verfahren und vorrichtung zur chemischen ionisation eines gasgemisches |
Publications (1)
Publication Number | Publication Date |
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EP3243210A1 true EP3243210A1 (de) | 2017-11-15 |
Family
ID=52780365
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
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EP15156526.4A Withdrawn EP3062332A1 (de) | 2015-02-25 | 2015-02-25 | Verfahren und Vorrichtung zur chemischen Ionisation eines Gasgemisches |
EP16709715.3A Pending EP3243210A1 (de) | 2015-02-25 | 2016-02-24 | Verfahren und vorrichtung zur chemischen ionisation eines gasgemisches |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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EP15156526.4A Withdrawn EP3062332A1 (de) | 2015-02-25 | 2015-02-25 | Verfahren und Vorrichtung zur chemischen Ionisation eines Gasgemisches |
Country Status (4)
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US (1) | US10224190B2 (de) |
EP (2) | EP3062332A1 (de) |
CN (1) | CN107873105B (de) |
WO (1) | WO2016135179A1 (de) |
Families Citing this family (2)
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WO2018011861A1 (ja) * | 2016-07-11 | 2018-01-18 | 株式会社島津製作所 | 分析装置 |
US20240249930A1 (en) * | 2023-01-19 | 2024-07-25 | Thermo Fisher Scientific (Bremen) Gmbh | Ion Beam Focusing |
Family Cites Families (26)
Publication number | Priority date | Publication date | Assignee | Title |
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AT403214B (de) | 1991-10-21 | 1997-12-29 | Ionentechnik Ges M B H | Verfahren zur analyse von gasgemischen |
AT1637U1 (de) | 1995-01-05 | 1997-08-25 | Lindinger Werner Dr | Verfahren zur gewinnung eines ionenstroms |
DE19523859C2 (de) | 1995-06-30 | 2000-04-27 | Bruker Daltonik Gmbh | Vorrichtung für die Reflektion geladener Teilchen |
DE19517507C1 (de) * | 1995-05-12 | 1996-08-08 | Bruker Franzen Analytik Gmbh | Hochfrequenz-Ionenleitsystem |
US5811800A (en) | 1995-09-14 | 1998-09-22 | Bruker-Franzen Analytik Gmbh | Temporary storage of ions for mass spectrometric analyses |
AT406206B (de) | 1997-04-15 | 2000-03-27 | Lindinger Werner Dr | Gewinnung von nh4+-ionen |
US6107628A (en) | 1998-06-03 | 2000-08-22 | Battelle Memorial Institute | Method and apparatus for directing ions and other charged particles generated at near atmospheric pressures into a region under vacuum |
DE10010902A1 (de) | 2000-03-07 | 2001-09-20 | Bruker Daltonik Gmbh | Tandem-Massenspektrometer aus zwei Quadrupolfiltern |
GB2389452B (en) | 2001-12-06 | 2006-05-10 | Bruker Daltonik Gmbh | Ion-guide |
AT413463B (de) | 2003-12-16 | 2006-03-15 | Hansel Armin Dr | Verfahren zur gewinnung eines ausgangs-ionenstroms |
US8003934B2 (en) * | 2004-02-23 | 2011-08-23 | Andreas Hieke | Methods and apparatus for ion sources, ion control and ion measurement for macromolecules |
JP4384542B2 (ja) * | 2004-05-24 | 2009-12-16 | 株式会社日立ハイテクノロジーズ | 質量分析装置 |
US7183545B2 (en) | 2005-03-15 | 2007-02-27 | Agilent Technologies, Inc. | Multipole ion mass filter having rotating electric field |
WO2008094288A2 (en) * | 2006-06-29 | 2008-08-07 | Ionwerks, Inc. | Neutral/ion reactor in adiabatic supersonic gas flow for ion mobility time-of flight mass spectrometry |
US7564025B2 (en) * | 2007-02-28 | 2009-07-21 | Agilent Technologies, Inc. | Multipole devices and methods |
US8124930B2 (en) * | 2009-06-05 | 2012-02-28 | Agilent Technologies, Inc. | Multipole ion transport apparatus and related methods |
DE102010030872A1 (de) | 2010-07-02 | 2012-01-05 | Robert Bosch Gmbh | Verfahren zum Bestimmen einer Korrekturkennlinie |
NZ605860A (en) | 2010-07-19 | 2015-04-24 | Summa Health System | Use of vitamin c, and chromium-free vitamin k or 2-methyl-1,4-naphthalendione, and compositions thereof for treating a polycystic disease |
US9145874B2 (en) * | 2010-08-09 | 2015-09-29 | Msnw Llc | Apparatus, systems and methods for establishing plasma and using plasma in a rotating magnetic field |
GB201021360D0 (en) | 2010-12-16 | 2011-01-26 | Thermo Fisher Scient Bremen Gmbh | Apparatus and methods for ion mobility spectrometry |
GB201104238D0 (en) | 2011-03-14 | 2011-04-27 | Micromass Ltd | Mass spectrometer |
US8969798B2 (en) * | 2011-07-07 | 2015-03-03 | Bruker Daltonics, Inc. | Abridged ion trap-time of flight mass spectrometer |
US8927940B2 (en) | 2011-06-03 | 2015-01-06 | Bruker Daltonics, Inc. | Abridged multipole structure for the transport, selection and trapping of ions in a vacuum system |
GB2508574B (en) * | 2012-06-24 | 2014-12-17 | Fasmatech Science And Technology Sa | Improvements in and relating to the control of ions |
AT514744A1 (de) | 2013-08-19 | 2015-03-15 | Universität Innsbruck | Einrichtung zur Analyse eines Probegases umfassend eine Ionenquelle |
US20160181080A1 (en) | 2014-12-23 | 2016-06-23 | Agilent Technologies, Inc. | Multipole ion guides utilizing segmented and helical electrodes, and related systems and methods |
-
2015
- 2015-02-25 EP EP15156526.4A patent/EP3062332A1/de not_active Withdrawn
-
2016
- 2016-02-24 US US15/552,872 patent/US10224190B2/en active Active
- 2016-02-24 WO PCT/EP2016/053833 patent/WO2016135179A1/de active Application Filing
- 2016-02-24 EP EP16709715.3A patent/EP3243210A1/de active Pending
- 2016-02-24 CN CN201680018368.8A patent/CN107873105B/zh active Active
Also Published As
Publication number | Publication date |
---|---|
CN107873105B (zh) | 2020-08-18 |
EP3062332A1 (de) | 2016-08-31 |
WO2016135179A1 (de) | 2016-09-01 |
US10224190B2 (en) | 2019-03-05 |
US20180047550A1 (en) | 2018-02-15 |
CN107873105A (zh) | 2018-04-03 |
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