Ion deflection system for a multi-functional inductively coupled plasma mass spectrometer

Abstract

A kind of ion deflection system of multifunctional inductively coupled plasma mass spectrometer, including core deflection lens group, ion focusing lens group and assembly part;The ion deflection system can make the flight direction of ion with certain angle deflection;And, by adjusting the direct current voltage applied on core deflection lens group and ion focusing lens group, it can be switched between "full pass mode" and "pre-screening mode".The arc cylindrical ion deflection system of inductively coupled plasma mass spectrometry provided by the utility model can effectively separate the ion beam generated in ion source from neutral substance and photon, overcome the shortcomings of existing ion deflection system, realize two different deflection modes, and through the implementation of the two deflection modes, user can flexibly select according to application field and different measured samples.

Description

Technical Field

[0001] This utility model relates to the field of inductively coupled plasma mass spectrometry, and in particular to an ion deflection system for a multifunctional inductively coupled plasma mass spectrometer. Background Technology

[0002] A typical structure of an inductively coupled plasma mass spectrometry (ICP-MS) system 200 is as follows: Figure 1 As shown, this includes a plasma-based ion source; this ion source is used to generate plasma to break down sample molecules into atoms, which are then ionized to prepare for elemental analysis. In typical operation, the liquid sample is atomized, i.e., converted into an aerosol (fine spray or mist), by a gas-driven (typically argon) nebulizer 201, and coarse aerosol is removed in the nebulization chamber 202, guiding the remaining fine aerosol into the plasma generated by the plasma source. The plasma source is often configured as a flow-through plasma torch 203 with two or more concentric tubes. Typically, a plasma-forming gas (argon) flows through the inner tubes of the torch and is excited into plasma by a suitable energy source, such as radio frequency (RF), powered load coil 204. The aerosol flows through the coaxial central tube of the torch 203 and is emitted into the generated plasma, which, upon exposure to the plasma, breaks down sample molecules into atoms, or alternatively, partially breaks down sample molecules into molecular fragments and ionizes these atoms or molecular fragments; these analyte atoms or molecular fragments, after ionization, generate an ion beam. Since these ions are not generated in a vacuum region, they gradually transition to a high vacuum region via sampling cone 205 and interception cone 206. After entering the high vacuum region, the ion beam is focused by extraction lens 207 and then enters off-axis or deflection lens 208.

[0003] The plasma used as an ion source in ICP-MS cannot completely decompose all components of the sample into ions. Some undecomposed neutral substances are introduced into the subsequent collisional reaction cell and quadrupole along with the ion beam through the interface. Simultaneously, the high-temperature plasma generates strong photons. These neutral substances can contaminate the subsequent ion microscope and collisional reaction cell, and also produce new interfering ions when colliding with the collisional reaction gas in the collisional reaction cell. Photons also generate significant detection noise. Therefore, effective methods are needed to separate neutral substances and photons from analyte ions before the ion beam enters the collisional reaction cell. Current commercial instruments typically use off-axis or deflection methods to separate the ion beam from neutral substances and photons.

[0004] Figure 1This is a typical off-axis method. After passing through the off-axis or deflection lens 208, the ions are separated from photons and neutral substances, and then enter the collision reaction cell 209. After eliminating interfering ions through collisions or reactions, the ions are focused by the collision reaction cell exit lens 210 and enter the secondary off-axis lens 211. The second off-axis movement can eliminate the influence of neutral substances in the collision reaction cell on subsequent quality screening, improving the signal-to-noise ratio. The ion beam after the second off-axis movement enters the mass analyzer 212. The mass analyzer generally adopts a quadrupole structure or other methods such as a sector magnetic field or a time-of-flight (TOF) analyzer. It uses an alternating electric field, or a combination of electric and magnetic fields, to perform spectral decomposition of the ionized ions according to their mass-to-charge ratio m / z. Then, the ion detector 213 can count each type of ion with a given m / z ratio arriving at the ion detector from the mass analyzer. The intensity of each peak indicates the concentration (or abundance) of the corresponding element in the sample.

[0005] Besides the off-axis method mentioned above, it is known that in ICP-MS systems, a 90-degree deflection between the ion source and the collision cell separates neutral substances and photons from analyte ions. The advantage of this 90-degree deflection is that it ensures more thorough separation of the large amount of neutral substances generated in the ion source, thus keeping the collision cell clean for a longer period, reducing performance degradation caused by contamination, and decreasing cleaning frequency and maintenance costs. The working principle of existing 90-degree deflection systems is as follows: Figure 2 (a) and Figure 2 As shown in (b).

[0006] Figure 2 (a) The 90-degree deflection lens shown uses a single circular rod for deflection. Figure 2 (b) illustrates a quadrupole deflection method. The ion beam generated by the ion source gradually transitions to the high vacuum region through sampling cones 301 and 401 and retrieval cones 302 and 402. After entering the high vacuum region, the ion beam is first focused by extraction lenses 303 and 403; then, the deflection focusing lens group 304, 404 and 305, 405 focuses the ions to the center of a single circular rod 306 or quadrupole 406 deflection lens. After passing through the focal point and being deflected, the ions diverge again, and are then refocused by another set of symmetrical deflection exit focusing lens groups 304, 404 and 305, 405. In conjunction with the collision reaction cell inlet focusing lenses 307 and 407, the ions are focused into the small hole in the middle of the collision reaction cell inlet lenses 308 and 408, and after passing through the collision reaction cells 309 and 409, they exit from the collision reaction cell outlet lenses 310 and 410.

[0007] In ICP-MS, the initial kinetic energies of ions generated by the ion source are not uniform, generally ranging from 1 eV to 10 eV. The kinetic energy of ions generally increases with increasing ion mass number (but not linearly); that is, ions of lighter elements have lower initial kinetic energies, while ions of heavier elements have higher initial kinetic energies. The above is as follows... Figure 2 In the first single-rod deflection method shown in (a), all ions within the aforementioned ion kinetic energy range are simultaneously deflected and enter the subsequent collision reaction cell. The advantage of this method is its high ion throughput; all ions use consistent ion mirror parameters, making tuning relatively simple. However, because it cannot perform ion discrimination to a certain extent, the number of ions entering the collision reaction cell is relatively large, leading to a decrease in collision or reaction efficiency. Especially when the sample matrix is ​​complex, it can result in incomplete elimination of interfering ions, thus affecting the accuracy of the test results. Furthermore, this ion deflection method does not have a vertical focusing lens, causing ions to diverge in the direction perpendicular to the deflection during flight. This effect is exacerbated by the mutual thrust between positive ions when the number of ions in the ion beam is large. The second method described above... Figure 2 (b) shows a quadrupole deflection method that is the opposite of that of a single circular rod. It can selectively allow ions with a certain range of kinetic energy to pass through by adjusting the DC voltage on the quadrupole, thereby performing a certain pre-screening before the ion beam enters the collision reaction cell, reducing the number of ions entering the collision reaction cell, and thus improving the collision reaction efficiency during sample analysis. However, the disadvantages are that on the one hand, a certain amount of sensitivity will be lost, and on the other hand, the deflection electric field curve must be optimized for ions with different mass numbers during tuning, thereby generating ion deflection scanning curves, which increases the complexity of the tuning process.

[0008] In summary, the existing 90-degree ion deflection methods in inductively coupled plasma mass spectrometers each have certain limitations. A more flexible 90-degree ion deflection method is needed. On the one hand, it can efficiently focus the analyte ions and complete the 90-degree deflection. On the other hand, users can selectively adopt either the "all-pass mode" (all ions are deflected and enter the subsequent collision reaction cell or quadrupole) or the "pre-screening mode" (only ions with a mass number close to the analyte ion are deflected before entering the subsequent collision reaction cell or quadrupole) according to their own application needs. This allows for flexible trade-offs in terms of sensitivity, ease of operation, and interference elimination capabilities. Utility Model Content

[0009] The purpose of this invention is to solve the problems existing in the prior art and to propose a multifunctional arc-shaped cylindrical ion deflection system for inductively coupled plasma mass spectrometry analysis.

[0010] This invention provides a multifunctional arc-shaped cylindrical ion deflection system for inductively coupled plasma mass spectrometry, comprising a core deflection lens group, an ion focusing lens group, and an assembly part.

[0011] The core deflection lens group includes a first arc-shaped cylindrical deflection lens, a second arc-shaped cylindrical deflection lens, and N symmetrically arranged ion kinetic energy adjustment lenses; the first and second arc-shaped cylindrical deflection lenses are concentrically arranged; the outer arc surface of the first arc-shaped cylindrical deflection lens and the inner arc surface of the second arc-shaped cylindrical deflection lens form an ion deflection flight channel;

[0012] The ion focusing lens group consists of N symmetrically arranged inlet or outlet focusing lenses, located at the inlet and outlet of the ion deflection flight channel, respectively; the inlet focusing lens and the outlet focusing lens are distributed at a certain angle, so that the flight direction of the ions is deflected at that angle;

[0013] The assembly includes a fixed bracket; the core deflecting lens group and the ion focusing lens group are fixedly mounted on the fixed bracket.

[0014] Furthermore, the system also includes vertical focusing lenses disposed above and below the ion deflection flight channel formed by the first arc-shaped cylindrical deflecting lens and the second arc-shaped cylindrical deflecting lens.

[0015] Furthermore, the system also includes a terminal block, through which the core deflecting lens group and the ion focusing lens group are respectively connected to different positions on the terminal block via connecting wires, so as to provide the required DC voltage to each lens group through the terminal block.

[0016] Furthermore, a first (or first group) DC voltage is applied to the ion focusing lens group; the same second (or second group) DC voltage is applied to the ion kinetic energy adjusting lens and the first arc-shaped cylindrical deflection lens; and a third DC voltage is applied to the second arc-shaped cylindrical deflection electrode.

[0017] Furthermore, by adjusting the settings of each of the DC voltages, the switching between "pre-screening mode" and "full-pass mode" can be achieved; wherein, when the difference between the first (or first group) DC voltage and the second (or second group) DC voltage is less than a certain voltage value, the deflection flight of ions in the system is in "pre-screening mode"; when the difference between the first (or first group) DC voltage and the second (or second group) DC voltage is greater than a certain voltage value, the deflection flight of ions in the system is in "full-pass mode".

[0018] Furthermore, a fourth DC voltage is applied to the vertical focusing lens.

[0019] Furthermore, the second arc-shaped cylindrical deflecting lens has an opening in the middle so that neutral substances and photons generated in the ion source can pass through and fly out of the ion deflection system.

[0020] Furthermore, the inlet or outlet focusing lens and / or ion kinetic energy regulating lens are annular electrodes and / or sheet-shaped or other shaped electrodes.

[0021] Furthermore, a round rod-shaped electrode is used to replace the first arc-shaped cylindrical deflection lens.

[0022] Furthermore, the focusing lenses at the inlet or outlet are symmetrically or asymmetrically distributed, with the same or different shapes, and the same or different numbers; the ion kinetic energy regulating lenses at the inlet and outlet are symmetrically or asymmetrically distributed, with the same or different shapes, and the same or different numbers.

[0023] This invention provides an arc-shaped cylindrical ion deflection system for inductively coupled plasma mass spectrometry (ICP-MS). On one hand, it effectively separates the ion beam generated in the ion source from neutral substances and photons. On the other hand, it overcomes the shortcomings of existing ion deflection systems by implementing two different deflection modes: a "screening mode" and a "full-pass mode." In the "full-pass mode," the DC voltage applied to the second arc-shaped cylindrical deflection lens 104 is adjusted to pre-screen ions in the ion beam, deflecting and focusing only ions with mass numbers close to those being analyzed. This reduces the number of ions entering the collision reaction cell, improves collision reaction efficiency, reduces interference, and enhances analytical accuracy. The "full-pass mode" maintains a fixed DC voltage across all deflection lens groups, allowing ions of all mass numbers to be deflected and focused simultaneously, further improving sensitivity and simplifying the ion lens optimization process. By implementing these two deflection modes, customers can flexibly choose according to the application field and the sample being measured. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a typical dual-off-axis mode inductively coupled plasma mass spectrometry (ICP-MS) system in the prior art;

[0025] Figure 2 This is a schematic diagram illustrating the principle of a 90-degree deflecting ion lens in existing technology; among which, Figure 2 (a) is a schematic diagram of a single round rod deflected at 90 degrees; Figure 2 (b) Schematic diagram of a quadrupole deflecting 90 degrees;

[0026] Figure 3 This is a schematic diagram of the arc-shaped cylindrical ion deflection system for inductively coupled plasma mass spectrometry analysis in Embodiment 1 of this utility model;

[0027] Figure 4This is a simulation diagram of the arc-shaped cylindrical deflecting lens structure and ion flight trajectory in Embodiment 1 of this utility model; wherein, Figure 4 (a) is a schematic diagram of the dimensions of the curved cylindrical deflection lens; Figure 4 (b) is a schematic diagram of the ion flight trajectory simulation; Figure 4 (c) is a structural diagram after the overall assembly is completed;

[0028] Figure 5 This is a schematic diagram of the fixed support structure of the arc-shaped cylindrical ion deflection system of this utility model;

[0029] Figure 6 This is a circuit connection diagram of the system in Embodiment 1 of this utility model;

[0030] Figure 7 This is a schematic diagram of the arc-shaped cylindrical ion deflection system for inductively coupled plasma mass spectrometry analysis in Embodiment 1 of this utility model; wherein, Figure 7 (a) is a schematic diagram of the deflection lens and the ion flight radius; Figure 7 (b) is a schematic diagram of the ion flight trajectory under the "pre-screening mode";

[0031] Figure 8 This is a schematic diagram illustrating the simulation results of ion flight trajectories under two deflection modes in Embodiment 1 of this utility model; wherein, Figure 8 (a) shows the simulation results in the "pre-screening" mode; Figure 8 (b) shows the simulation results in "All-through" mode;

[0032] Figure 9 This is a schematic diagram of the principle of Embodiment 2 of this utility model;

[0033] Figure 10 This is a schematic diagram of the principle of Embodiment 3 of this utility model;

[0034] Figure 11 This is a schematic diagram of the principle of Embodiment 4 of this utility model. Detailed Implementation

[0035] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0036] In the description of this utility model, it should be understood that the terms "longitudinal", "radial", "orthogonal", "opposite", "one end", "the other end", etc., used in this utility model to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0038] Example 1

[0039] like Figure 3 As shown, this utility model provides an arc-shaped cylindrical ion deflection system 100 for inductively coupled plasma mass spectrometry analysis, which mainly consists of three parts: a core deflection lens group, an ion focusing lens (group), and an assembly part.

[0040] The core deflecting lens group comprises a first arc-shaped cylindrical deflecting lens 103, a second arc-shaped cylindrical deflecting lens 104, and N (N = 1, 2, 3…) symmetrically or asymmetrically arranged annular (or other shaped) ion kinetic energy adjusting lenses 102. Preferably, it may also include two vertical focusing lenses 106. The first arc-shaped cylindrical deflecting lens 103 and the second arc-shaped cylindrical deflecting lens 104 are concentric in the arc direction; the outer arc surface of the first arc-shaped cylindrical deflecting lens 103 and the inner arc surface of the second arc-shaped cylindrical deflecting lens 104 form the ion deflection flight channel.

[0041] The ion focusing lens (group) is composed of N (N=1, 2, 3...) symmetrically or asymmetrically arranged annular (or other shaped) focusing lenses 101, which are located at the inlet and outlet of the ion deflection system 100, respectively.

[0042] The assembly part mainly includes a fixed bracket 105, a wiring terminal 113, and insulating gaskets 107 and 109, etc.

[0043] like Figure 3As shown, the inlet or outlet focusing lens 101, the ion kinetic energy adjusting lens 102, the first and second arc-shaped cylindrical deflection lenses 103 and 104, and the vertical focusing lens 106 are all fixedly mounted on the fixed bracket 105. Furthermore, the inlet focusing lens 101 and the outlet focusing lens 101 are distributed at a 90-degree angle. In other embodiments, this angle can be any suitable angle between 0 and 360 degrees. The first and second arc-shaped cylindrical deflection lenses 103 and 104 are disposed within the fixed bracket 105, causing the ion flight direction to deflect by 90 degrees. As shown, the inlet or outlet focusing lenses 101 at the inlet and outlet ends are symmetrically arranged; the ion kinetic energy adjusting lenses 102 at the inlet and outlet ends are also symmetrically arranged. However, in other embodiments, the inlet and outlet ends can employ lenses of different shapes, numbers, and arrangements.

[0044] refer to Figure 4 (a) To achieve the objective of this invention, the radii of the first and second arc-shaped cylindrical deflecting lenses 103 and 104 are optimized such that the center line AB of the inlet ion focusing lens group 101 and the ion kinetic energy adjusting lens 102 intersects the center line CD of the outlet ion focusing lens group within the interior of the first arc-shaped cylindrical deflecting lens 103 and the second arc-shaped cylindrical deflecting lens 104. Preferably, the center position E of the line connecting the tangent points GH and JK of the first arc-shaped cylindrical deflecting lens 103 and the second arc-shaped cylindrical deflecting lens 104 located inside the lens group is the center position of the arc-shaped cylindrical ion deflection system. Figure 4 (b) shows the simulation results of ion flight. As can be seen from the figure, by optimizing the voltage of the ion mirror group, the ion beam is perfectly focused to the center position E of the deflecting lens group. After the ion beam passes point E, it begins to diverge and is then focused by the exit ion focusing lens 101 onto the inlet of the collision reaction cell. The focusing lens at the inlet end is used to focus the ion beam entering the deflecting lens to the center of the deflecting lens, and the focusing lens at the outlet end is used to focus the deflected ion beam onto the subsequent collision reaction cell.

[0045] Specifically, for the fixed bracket 105, as shown in the example Figure 5As shown, the fixed support 105 of the arc-shaped cylindrical ion deflection system 100 includes an upper frame and a lower frame. The upper frame includes two radial sides 105-11 and 105-12 and two arc sides 105-13 and 105-14. The circles corresponding to the two arc sides 105-13 and 105-14 are concentric circles, and the two radial sides 105-11 and 105-12 and the two arc sides 105-13 and 105-14 form a fan-shaped ring. The lower frame has the same shape as the upper frame and is vertically spaced from the upper frame by a certain distance. Between the two radial sides of the upper and lower frames are the two side faces 105-2 and 105-3 of the fixed support 105, and the two side faces 105-2 and 105-3 are perpendicular to each other. Between the two arc sides of the upper and lower frames are the two cylindrical faces 105-4 and 105-5 of the fixed support 105.

[0046] Both side surfaces 105-2 and 105-3 are provided with columnar protrusions for accommodating the inlet focusing lens, the outlet focusing lens 101, and the ion kinetic energy adjusting lens 102. The inner arc-shaped cylindrical surface 105-4 has an opening for positioning the rotation angle of the first arc-shaped cylindrical deflection lens 103. The cylindrical surface 105-5 also has an elongated hole for mounting and fixing the second arc-shaped cylindrical deflection lens 104.

[0047] The fixing bracket 105 is made of metal or non-metal materials. In the arc-shaped cylindrical ion deflection system 100, the fixing bracket 105 only serves to fix and support other components, and does not directly deflect the ions.

[0048] like Figure 3 As shown, the fixed bracket 105 has an axisymmetric structure. The inlet focusing lens, the outlet focusing lens 101, the inlet ion kinetic energy adjusting lens 102 and the outlet ion kinetic energy adjusting lens 102 have the same composition and structure. This embodiment does not specifically limit its inlet and outlet. In use, one can be selected as the inlet and the other as the outlet according to the actual installation position and other requirements.

[0049] like Figure 3In the embodiment shown, the inlet focusing lens, the inlet ion kinetic energy regulating lens, the outlet ion kinetic energy regulating lens, and the outlet focusing lens all include a first annular electrode 101 and a second annular electrode 102; the first annular electrode 101 and the second annular electrode 102 are fixed on the fixed bracket 105. Specifically, the first annular electrode 101 and the insulating ring 107 are fixed to the outside of the columnar receiving space on the side facade of the fixed bracket 105; the second annular electrode 102 is sleeved inside the insulating ring 108 and fixed within the columnar receiving space on the side facade of the fixed bracket 105.

[0050] The two side faces of the fixed bracket 105 are perpendicular to each other, and the inlet focusing lens and the outlet focusing lens are distributed at 90 degrees.

[0051] The number of annular electrodes for the inlet and outlet focusing lenses can be selected according to actual needs.

[0052] The arc-shaped cylindrical deflecting lens includes a first arc-shaped cylindrical deflecting lens 103 and a second arc-shaped cylindrical deflecting lens 104.

[0053] The first arc-shaped cylindrical deflecting lens 103 is arc-shaped cylindrical and is disposed on the inner side of the fixed bracket 105 and fixed to the fixed bracket 105. Specifically, the first arc-shaped cylindrical deflecting lens 103 has columnar protrusions at both the upper and lower ends, which are connected to the vertical focusing lens 106 through two upper and lower PEEK insulating pads 112, but are not conductive. The connecting wire 114 is also connected to the columnar protrusions. The first arc-shaped cylindrical deflecting lens 103 has two round holes on its side, which are connected to the inner arc side surface 105-4 of the fixed bracket 105 through a PEEK positioning pin, and the rotation angle is positioned accordingly.

[0054] The second arc-shaped cylindrical deflecting lens 104 is also arc-shaped cylindrical with an opening in the middle to allow neutral substances and photons generated in the ion source to pass through. The second arc-shaped cylindrical deflecting lens 104 is disposed within the fixed bracket 105 and fixedly connected to the fixed bracket 105 by epoxy resin adhesive. Specifically, the outer arc surface of the second arc-shaped cylindrical deflecting lens 104 is connected to the cylindrical surface 105-5 of the fixed bracket 105 by insulating epoxy resin adhesive, but is not conductive. The second arc-shaped cylindrical deflecting lens 104 and the first arc-shaped cylindrical deflecting lens 103 are concentrically arranged, and their concentricity is ensured by specially designed assembly fixtures.

[0055] The second cylindrical deflection lens 104 has an opening at its center, which corresponds to the opening on the cylindrical surface 105-4, and is used to allow neutral substances, photons, etc. to fly out of the arc-shaped cylindrical ion deflection system 100.

[0056] Preferably, a fan-shaped vertical focusing lens 106 is provided on the outside of the upper frame and / or lower frame of the fixed bracket 105. Figure 3 The diagram shows a configuration where vertical focusing lenses 106 are mounted on the outer sides of both the upper and lower frames of the fixed bracket 105. The vertical focusing lenses 106 are fan-shaped, their shape matching that of the fixed bracket 105. An insulating sheet 109 is provided between the vertical focusing lenses 106 and the fixed bracket 105, and they are secured to the outer sides of the upper and lower frames of the fixed bracket 105 with insulating screws (such as nylon or PEEK screws). The vertical focusing lenses 106 are used to further focus ions in the arc-shaped cylindrical ion deflection system 100 in both upward and downward directions.

[0057] Preferably, the bottom of the fixing bracket 105 is fixed to the fixing base 110. For example... Figure 3 As shown, an insulating sheet 111 is provided between the fixed base 110 and the vertical focusing lens 106. The fixed base 110 can position the entire fan-shaped electrostatic field ion deflection lens 100 in a suitable position on the inductively coupled plasma mass spectrometer.

[0058] The arc-shaped cylindrical ion deflection system 100 further includes a terminal block 113. Each relevant lens in the arc-shaped cylindrical ion deflection system 100, namely the inlet focusing lens, the outlet focusing lens, the first and second arc-shaped cylindrical deflection lenses, the vertical focusing lens, etc., is connected to different positions on the terminal block 113 via connecting wires 114, so that the terminal block 113 can provide the required DC voltage to each lens. Preferably, the terminal block 113 is fixedly connected to the fixing bracket 105 via a terminal block fixing bracket.

[0059] After ions enter the arc-shaped cylindrical ion deflection system 100 through the inlet focusing lens, their flight direction is deflected by 90 degrees under the combined action of the first arc-shaped cylindrical deflection lens 103 and the second arc-shaped cylindrical deflection lens 104, which are both subjected to DC voltage, and they exit from the outlet focusing lens. To prevent the ion beam from defocusing in the vertical direction during flight, a fan-shaped vertical focusing lens 106 is arranged above and below the fan-shaped electrostatic field ion deflection lens 100 to better focus the ion beam in the vertical direction. Each relevant lens is connected to a different position on the terminal block 113 via connecting wires 114, so that the required DC voltage can be provided to each lens through the terminal block. The specific voltage application method is as follows: Figure 6 As shown.

[0060] like Figure 6As shown, a first DC voltage U1 is applied to the inlet or outlet focusing lens 101; the same DC voltage U2 is applied to the ion kinetic energy adjusting lens 102 and the first arc-shaped cylindrical deflection lens 103, generally between -10V and -1000V; another set of DC voltages U3 is applied to the second arc-shaped cylindrical deflection electrode 104, ranging from +50V to -300V; and a fourth DC voltage U4 is applied to the vertical focusing lens 106.

[0061] Depend on Figure 6 As can be seen, the arc-shaped cylindrical ion deflection system has four sets of DC voltages. By adjusting the settings of each voltage, two different deflection modes can be achieved, namely "pre-screening mode" and "full-pass mode", allowing users to more flexibly select the mode according to the needs of sample analysis.

[0062] The working principle of the arc-shaped cylindrical ion deflection system 100 for inductively coupled plasma mass spectrometry analysis of this utility model is described below.

[0063] When ions enter the ion kinetic energy adjusting lens 102 of the core deflection lens group of the system 100, they possess a certain initial kinetic energy, generally between 1-10 eV (electron volts), mostly between 2-8 eV. The ions fly into the ion deflection flight channel from the center of the ion kinetic energy adjusting lens 102. Under the influence of the arc-shaped electrostatic field formed by the first arc-shaped cylindrical deflection lens 103 and the second arc-shaped cylindrical deflection lens 104, they will move in an arc along a certain deflection radius. The deflection radius depends on the ion's kinetic energy, flight speed, and deflection electric field strength, conforming to the following formula:

[0064]

[0065] In the formula, q is the charge number of the ion, E is the intensity of the ion deflection electric field, m is the mass of the ion, v is the flight speed of the ion, and r is the deflection radius of the ion.

[0066] Due to the total kinetic energy of ions Therefore, the deflection radius r of ion flight is equal to:

[0067]

[0068] This shows that the ion deflection radius *r* is independent of the ion's mass, but rather depends on the ion's kinetic energy and the strength of the deflection electric field. Therefore, ions cannot be distinguished by mass when flying in the deflection electric field, but they can be distinguished by their kinetic energy. For inductively coupled plasma mass spectrometry (ICP-MS), the kinetic energies of the ions generated by the ion source are different; generally, lighter ions have lower kinetic energies, while heavier ions have higher kinetic energies. Therefore, this can be used to perform preliminary screening of ions in the ion beam.

[0069] In this utility model, reference is made to, for example Figure 7 (a) shows the schematic diagram. In the diagram, the outer radius of the first arc-shaped cylindrical deflecting lens 103 is r1, and the inner radius of the second arc-shaped cylindrical deflecting lens is r2. The ion deflection channel is located within the arc-shaped channel between r1 and r2. Ideally, ions enter the center of the kinetic energy regulating lens 102 from the center of the deflection inlet ion focusing lens 101. The DC bias voltage U2 applied to the kinetic energy regulating lens 102 is more negative than U1 applied to the inlet or outlet focusing lens 101, thus increasing the kinetic energy of the ions. Under a suitable deflection electric field strength, ions with a certain kinetic energy will fly along the deflection radius between r1 and r2, that is:

[0070]

[0071] According to the previous formula, the deflection radius of an ion is related to its kinetic energy and the strength of the deflection electric field; the kinetic energy E of the ion... k The initial kinetic energy E generated by the ion source ki The additional kinetic energy E generated on the kinetic energy adjustment lens kU ,Right now:

[0072] E k =E ki +E kU

[0073] Among them, E ki E is related to the mass number of the ion. kU This is related to the voltage difference applied to the ion kinetic energy regulating lens 102 and the inlet or outlet focusing lens 101. The electric field strength at the intersection of the centers of these two ion mirrors is:

[0074]

[0075]

[0076] The ions generated by ICP, the ion source of inductively coupled plasma, are generally monovalent positive ions, therefore q = 1; the intensity of the deflection electric field E is related to the voltage applied to the first curved cylindrical deflector 103 and the second curved cylindrical deflector 104, as well as the distance between them:

[0077]

[0078] Where d refers to the distance between the outer arc of the first deflecting lens 103 and the inner arc of the second deflecting lens 104 (d = r2 - r1), therefore:

[0079]

[0080] This formula shows that:

[0081] 1) When U1, U2, and U3 remain constant, ions with different kinetic energies will deflect along different deflection radii;

[0082] 2) When U1 and U2 remain constant, changing U3 will cause ions with different kinetic energies to deflect to the same radius;

[0083] 3) The more negative the U2 voltage, the greater the total kinetic energy of the ions, and the closer the deflection radii of ions with adjacent initial kinetic energies. (That is, when U2 is more negative, the influence of initial kinetic energy on the ion deflection radius will be smaller).

[0084] This invention is designed based on the above principle. When ions deflect along the central radius r of the ion deflection flight channel, they can accurately enter the focusing lens of the subsequent collision reaction cell and be focused into the small hole in the middle of the entrance lens of the collision reaction cell; when the ion deflection radius is too small or too large, the ions will deflect to the outside of the collision reaction cell and thus cannot enter the subsequent collision reaction cell (e.g., Figure 7 (b) shows. By optimizing the aperture of the focusing lens in the collision reaction cell and the distance between it and the deflection lens, the range of ions allowed to enter the collision reaction cell can be controlled.

[0085] Based on the above design method, this utility model can achieve two deflection modes in the same system, namely "pre-screening mode" and "full-pass mode", by changing the voltage applied to different components, which provides great convenience to users.

[0086] In the pre-screening mode, ions with specific kinetic energies can enter the subsequent collision reaction cell or quadrupole after passing through the system of this invention; in the all-pass mode, all ions can enter the subsequent collision reaction cell or quadrupole after passing through the system.

[0087] By adjusting the setting of the DC voltage applied to each lens, the pre-screening mode and the all-pass mode can be switched. (Reference) Figure 6The voltage application method described herein allows for ion deflection in a "pre-screening mode" when the voltage difference between U1 and U2 is less than a certain value (e.g., 100V, which is related to the mechanical structure dimensions of the deflection system); and a "full-pass mode" when the voltage difference between U1 and U2 is greater than a certain value (e.g., 100V, which is related to the mechanical structure dimensions of the deflection system). Furthermore, U3 and U4 need to be optimized separately for both modes. In the "pre-screening mode," U3 is optimized based on different ion mass numbers, while in the "full-pass mode," U3, like the other voltage sets, is a fixed value. Therefore, by simply changing the optimized values ​​of these voltage sets, the switching between the two deflection modes—the "pre-screening mode" and the "full-pass mode"—can be achieved.

[0088] Figure 8 This is a schematic diagram showing the simulation results of ion flight trajectories under two deflection modes in Embodiment 1 of this utility model. Figure 8 (a) shows the simulation results under the "pre-screening mode"; Figure 8 (b) shows the simulation results under "All-Pass Mode". The simulation results show that in "Pre-screening Mode", when an ion with a specific kinetic energy (e.g., 4 eV) is selected for analysis, ions with other kinetic energies (e.g., 3 eV, 5 eV, etc.) cannot enter the subsequent collision reaction cell or quadrupole. When "All-Pass Mode" is selected, it can be seen that all ions (with kinetic energies between 1 eV and 10 eV) can enter the subsequent collision reaction cell or quadrupole.

[0089] In actual testing, since not all ions enter the deflection lens along the center of the ion kinetic energy adjustment lens 102, but rather in the form of an ion beam, the actual ion screening efficiency will be slightly lower than the theoretical one. That is, a small number of ions with adjacent ion kinetic energy will still enter the subsequent collision reaction cell along with the ions with the selected ion kinetic energy. However, most of them have been eliminated, which will greatly improve the collision reaction efficiency of the ions to be tested in the collision reaction cell, thereby improving the accuracy of complex sample analysis.

[0090] Meanwhile, since U2 varies greatly in different modes, the vertical focusing of ions will also change. Therefore, this invention creatively adds two symmetrical vertical focusing lenses 106 to the arc-shaped cylindrical ion-converting lens system, and optimizes the DC voltage value U4 on these two lenses to achieve optimal vertical focusing of ions in different modes. This vertical focusing lens 106 can also significantly reduce the space charge effect in the analysis of high-matrix samples, effectively improving the internal standard recovery rate of such samples.

[0091] Example 2

[0092] like Figure 9As shown, this embodiment provides another ion deflection system 100 for a multifunctional inductively coupled plasma mass spectrometer. The ion deflection system 100 of the multifunctional inductively coupled plasma mass spectrometer described in this embodiment is basically the same in structure as that in Embodiment 1. The main difference is that in this embodiment, a round rod electrode 115 is used instead of an arc-shaped cylindrical electrode 103 as the first ion deflection lens.

[0093] In this embodiment, the inlet and outlet focusing lenses 101, the ion kinetic energy adjusting lens 102, and the vertical focusing lens are all configured in the same way as in Embodiment 1; the circuit connection method is also basically the same. The advantage of this embodiment is that the cylindrical electrode is easier to process than the arc-shaped cylindrical electrode.

[0094] Example 3

[0095] like Figure 10 As shown, the ion deflection system 100 of the multifunctional inductively coupled plasma mass spectrometer is described. The ion deflection system 100 of the multifunctional inductively coupled plasma mass spectrometer in this embodiment is basically the same in structure as that in Embodiment 1, with the main difference being the exit focusing lens.

[0096] In this embodiment, the inlet focusing lens 101, the ion kinetic energy regulating lens 102, the vertical focusing lens, etc., are all set in the same way as in Embodiment 1. The outlet focusing lens adopts a sheet electrode 116, and the ion beam focused by this electrode directly enters the small hole in the center of the collision reaction cell inlet electrode 117. The sheet electrode 116 is fixedly connected to the fixing bracket 105 using a connection and fixing method commonly used in the art, and the collision reaction cell inlet electrode 117 is connected to the collision reaction cell.

[0097] In this embodiment, setting the outlet focusing lens as a sheet electrode can reduce the volume of the deflection system, reduce the flight distance of ions from the deflection to the collision reaction cell, and at the same time reduce the volume of the vacuum chamber, thereby reducing the overall cost.

[0098] Example 4

[0099] like Figure 11 As shown, the ion deflection system 100 of the multifunctional inductively coupled plasma mass spectrometer is described. The ion deflection system 100 of the multifunctional inductively coupled plasma mass spectrometer in this embodiment is basically the same in structure as that in Embodiment 1. The main differences between the two are the inlet and outlet focusing lenses and the ion kinetic energy adjustment lens.

[0100] In this embodiment, the inlet and outlet focusing lenses 101 and the ion kinetic energy regulating lens 102 both employ sheet electrodes 116 and 118. The ion beam focused by these electrodes directly enters the small hole in the center of the collision reaction cell inlet electrode 117. The sheet electrodes 116 and 118 are fixedly connected to the fixing bracket 105 using a connection and fixing method commonly used in the art, and the collision reaction cell inlet electrode 117 is connected to the collision reaction cell.

[0101] In this embodiment, both the outlet focusing lens and the ion kinetic energy adjustment lens are set as sheet electrodes, which can further reduce the volume of the deflection system and the flight distance of ions from the deflection to the collision reaction cell. At the same time, a smaller vacuum chamber can be used, further reducing the overall cost of the machine.

[0102] The above description is merely a preferred embodiment of this utility model. It should be noted that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this utility model, and these improvements and substitutions should also be considered within the protection scope of this utility model. The basic principles, main features, and advantages of this utility model have been shown and described above. For those skilled in the art, it is obvious that this utility model is not limited to the details of the above preferred embodiments. The embodiments should be considered exemplary and non-limiting. The scope of this utility model is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included within this utility model.

[0103] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An ion deflection system for a multifunctional inductively coupled plasma mass spectrometer, comprising a core deflection lens group, an ion focusing lens group, and an assembly section; in, The core deflection lens group includes a first arc-shaped cylindrical deflection lens, a second arc-shaped cylindrical deflection lens, and N ion kinetic energy adjustment lenses; the first and second arc-shaped cylindrical deflection lenses are arranged concentrically; The outer arc surface of the first arc-shaped cylindrical deflecting lens and the inner arc surface of the second arc-shaped cylindrical deflecting lens form an ion deflection flight channel; The ion focusing lens group consists of N symmetrically arranged inlet focusing lenses or outlet focusing lenses, located at the inlet and outlet of the ion deflection flight channel, respectively; the inlet focusing lenses and outlet focusing lenses are distributed at a certain angle, so that the flight direction of the ions is deflected at that angle; The assembly includes a fixed bracket; the core deflecting lens group and the ion focusing lens group are fixedly mounted on the fixed bracket.

2. The ion deflection system according to claim 1, characterized in that, The system also includes vertical focusing lenses disposed above and below the ion deflection flight channel formed by the first arc-shaped cylindrical deflecting lens and the second arc-shaped cylindrical deflecting lens.

3. The ion deflection system according to claim 1, characterized in that, The system also includes a terminal block, through which the core deflecting lens group and the ion focusing lens group are connected to different positions on the terminal block via connecting wires, so as to provide the required DC voltage to each lens group through the terminal block.

4. The ion deflection system according to claim 1, characterized in that, A first or first group of DC voltages is applied to the ion focusing lens group; the same second or second group of DC voltages is applied to the ion kinetic energy adjusting lens and the first arc-shaped cylindrical deflection lens; a third DC voltage is applied to the second arc-shaped cylindrical deflection lens.

5. The ion deflection system according to claim 4, characterized in that, By adjusting the settings of each of the aforementioned DC voltages, the "pre-screening mode" and "full-pass mode" can be switched.

6. The ion deflection system according to claim 2, characterized in that, A fourth DC voltage is applied to the vertical focusing lens.

7. The ion deflection system according to claim 1, characterized in that, The second arc-shaped cylindrical deflecting lens has an opening in the middle so that neutral substances and photons generated in the ion source can pass through and fly out of the ion deflection system.

8. The ion deflection system according to claim 1, characterized in that, The inlet or outlet focusing lens and / or ion kinetic energy regulating lens are ring electrodes and / or sheet electrodes.

9. The ion deflection system according to claim 1, characterized in that, The first arc-shaped cylindrical deflecting lens is replaced with a round rod-shaped electrode.

10. The ion deflection system according to claim 1, characterized in that, The focusing lenses at the inlet or outlet are symmetrically or asymmetrically distributed, with the same or different shapes, and the same or different numbers; the ion kinetic energy regulating lenses at the inlet and outlet are symmetrically or asymmetrically distributed, with the same or different shapes, and the same or different numbers.

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