Ion guide and mass spectrometer

Abstract

In order to improve the robustness of an ion guide, an ion guide configured by arranging a plurality of rod electrodes (20) having a columnar shape in a circular shape is characterized in that the side surface of each of the rod electrodes (20) is provided with a recessed cutout portion (21) and a protruding portion (26), and the cutout portion (21) of one of the rod electrodes (20) is fitted in a non-contact state with the protruding portion (26) of the other rod electrode (20). Furthermore, the rod electrode (20) is disposed such that the inscribed circle of the rod electrode (20) on the inlet side is larger than the inscribed circle of the rod electrode (20) on the outlet side.

Description

Technical Field

[0001] The present invention relates to the technology of ion guide and mass spectrometer. Background Art

[0002] In a mass spectrometer, ions generated by an ion source are transported to a mass analyzer via an ion transport unit. Mass spectrometers using atmospheric pressure ionization typically employ a differential exhaust system that divides the vacuum chamber into multiple compartments, in order to transport ions generated at atmospheric pressure to the mass analyzer in a vacuum. In these cases, the ion transport unit is often located upstream of the mass analyzer in a differential exhaust chamber with a lower vacuum level and higher pressure. To achieve high sensitivity in mass analyzers, the ion transport unit requires both high ion acquisition efficiency and high ion focusing efficiency.

[0003] Ion guides typically use an ion guide method that focuses ions using a high-frequency electric field generated by applying a high-frequency voltage. Ion guides include an ion funnel method that stacks ring-shaped electrodes in the ion transport direction, and a multipole ion guide method consisting of multiple rod electrodes.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: U.S. Patent No. 10475633

[0007] Non-patent literature

[0008] Non-patent document 1: "Conical octopole ion guide: Design, focusing, and its application to the deposition of low energetic clusters", REVIEW OF SCIENTIFICINSTRUMENTS, 77, 013302, 2006 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] A multipole ion guide (hereinafter referred to as an ion guide) is supported in a vacuum chamber by a bracket made of an insulating material. In addition to ions, droplets are introduced into the ion guide, but it is desired that the droplets be discharged from the ion guide. At this time, the droplets are discharged to the outside from the gaps between the rod electrodes constituting the ion guide, but at this time, a portion of the discharged droplets adheres to the inner side of the bracket, and the inner side of the bracket is contaminated. As a result, the voltage that can be applied to the rod electrodes is reduced, or even when the same voltage value as before contamination is applied to the rod electrodes, the possibility of discharge due to the attached droplets on the inner side of the bracket increases. As a result, there is concern that the analytical performance and stability of the mass spectrometer may deteriorate.

[0011] Patent Document 1 and Non-Patent Document 1 describe increasing the number of rod electrodes (poles) to improve ion capture efficiency. Furthermore, Patent Document 1 and Non-Patent Document 1 describe arranging the rod electrodes at an angle along their length, gradually narrowing the internal space of the ion guide toward the ion exit. In this way, the techniques described in Patent Document 1 and Non-Patent Document 1 achieve an improvement in ion focusing efficiency.

[0012] However, none of the above-mentioned technologies discloses a structure for preventing the inner side of the stent from being contaminated by liquid droplets.

[0013] The present invention has been made in view of the above background, and an object of the present invention is to improve the robustness of an ion guide.

[0014] Solutions to Problems

[0015] In order to solve the above-mentioned problems, the ion guide of the present invention is composed of a plurality of columnar rod electrodes arranged in a circular shape. The above-mentioned ion guide is characterized in that a concave portion and a convex portion are provided on the side surface of each of the above-mentioned rod electrodes, and the above-mentioned concave portion of a certain above-mentioned rod electrode is embedded in the above-mentioned convex portion of other above-mentioned rod electrodes in a non-contact state.

[0016] Other solutions are described appropriately in the embodiments.

[0017] The effects of the invention are as follows.

[0018] According to the present invention, the robustness of the ion guide can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is a diagram showing the structure of a mass spectrometer used in the first embodiment.

[0020] Figure 2 This is a diagram showing the structure of an ion guide including twelve cylindrical rod electrodes.

[0021] Figure 3AThis is a diagram (part 1) showing only one of the rod electrodes constituting the ion guide.

[0022] Figure 3B This is a diagram (part 2) showing only one of the rod electrodes constituting the ion guide.

[0023] Figure 4 1 and 2 are diagrams showing a top view, a cross-sectional view, and an arrow view of one rod electrode according to the present embodiment.

[0024] Figure 5 It is a perspective view showing four of the twelve rod electrodes constituting the ion guide.

[0025] Figure 6 This diagram shows the gap between adjacent rod electrodes.

[0026] Figure 7 This is a diagram showing an example of an ion guide provided with a support (Part 1).

[0027] Figure 8 This is a diagram showing an example of an ion guide provided with a support (part 2).

[0028] Figure 9 It is a diagram showing other explanations of the features of the ion guide according to the first embodiment.

[0029] Figure 10 It is a diagram showing an ion guide according to the second embodiment.

[0030] Figure 11 It is a diagram showing an ion guide according to a third embodiment.

[0031] Figure 12 It is a diagram showing an ion guide according to a first modification.

[0032] Figure 13A This is a diagram (part 3) showing only one of the rod electrodes constituting the ion guide.

[0033] Figure 13B This is a diagram (fourth) showing only one of the rod electrodes constituting the ion guide.

[0034] Figure 14 It is a diagram showing an ion guide according to a second modification.

[0035] Figure 15A This is a diagram (part 5) showing only one of the rod electrodes constituting the ion guide.

[0036] Figure 15B This is a diagram (part six) showing only one of the rod electrodes constituting the ion guide.

[0037] Figure 16 It is a diagram showing an ion guide according to a third modified example.

[0038] Figure 17A This is a diagram (part 7) showing only one of the rod electrodes constituting the ion guide.

[0039] Figure 17B FIG. 8 is a diagram showing only one of the rod electrodes constituting the ion guide.

[0040] Figure 18 It is a diagram showing the structure of an ion guide according to a fourth embodiment.

[0041] Figure 19A This is a diagram (part 9) showing only one of the rod electrodes constituting the ion guide.

[0042] Figure 19B FIG. 10 is a diagram showing only one of the rod electrodes constituting the ion guide.

[0043] Figure 20 It is a perspective view showing two of the four rod electrodes constituting the ion guide.

[0044] Figure 21 This is a diagram showing the structure of a dodecapole ion guide in which twelve cylindrical rod electrodes are arranged in parallel according to a fifth embodiment.

[0045] Figure 22 This is a diagram showing an example of an ion guide provided with a support (part 3).

[0046] Figure 23 1 is a cross-sectional view showing an ion guide according to a sixth embodiment.

[0047] Figure 24 It is a diagram showing common features.

[0048] Figure 25 This is a partial enlarged view of the rod electrodes that make up the ion guide.

[0049] Figure 26 This is a diagram showing the structure of an ion guide of a comparative example (part 1).

[0050] Figure 27 This is a diagram (part 4) showing the structure of an ion guide provided with a support.

[0051] Figure 28 This is a diagram showing the structure of an ion guide of a comparative example (part 2).

[0052] Figure 29 This is a diagram (part 5) showing the structure of an ion guide provided with a support. DETAILED DESCRIPTION

[0053] Next, modes for carrying out the present invention (referred to as “embodiments”) will be described in detail with reference to the drawings as appropriate.

[0054] [First embodiment]

[0055] In the first embodiment, a mass spectrometer 1 is used which comprises twelve rod electrodes 20 (see Figure 2 ) is a dodecapole ion guide 200, wherein the twelve rod electrodes 20 are provided with a recessed portion 21 having a concave and arc-shaped shape.

[0056] (Mass Analyzer 1)

[0057] Figure 1 1 is a diagram showing the structure of a mass spectrometer 1 used in the first embodiment.

[0058] The mass spectrometer 1 is mainly composed of an ion source 100, an ion guide 200, an ion transport device 300, and a mass spectrometer 400. The ion guide 200, the ion transport device 300, and the mass spectrometer 400 are arranged inside a vacuum container 130. Figure 1 In FIG. 1 , the dotted line shows the control line for voltage, and the single-dot chain line shows the control line for information transmission.

[0059] The ion source 100 is primarily composed of an ion generator 110 and an ion source chamber 120. The ion source 100 can employ various ionization methods, including electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI). When generating ions from an introduced sample solution Q, the ion generator 110 sprays the generated ions into the ion source chamber 120.

[0060] When sample solution Q is ionized and sprayed, in addition to ions, a large number of droplets are also sprayed. Therefore, the interior of the ion source chamber 120 is evacuated (symbol E) to remove unnecessary droplets. For example, in the ESI method, electrostatic spraying and gas spraying within the ion generator 110 are used to reduce unnecessary droplets. This promotes vaporization of sample solution Q and improves ionization efficiency. Electrostatic spraying is performed by applying a high voltage to the ion generator 110 via the power supply 500. While also dependent on the flow rate of sample solution Q, the flow rate of the sprayed gas is approximately 0.5 to 10 L / min. Furthermore, inert gases such as nitrogen and argon are generally used in the ion generator 110. The flow rate of sample solution Q typically ranges from nL (nanoliters) / min to mL (milliliters) / min. Furthermore, to further improve ionization efficiency, a method is also commonly used in which the interior of the ion generator 110, which sprays ions and droplets, is heated with heated gas (maximum approximately 800°C). Generally, the flow rate of the heating gas is about 0.5 to 50 L / min, and an inert gas such as nitrogen or argon is used.

[0061] And, in Figure 1 In the structure, an opposing electrode 121 having a hole H1 is provided in front of the introduction electrode 122. Gas G is introduced from the hole H11 into the space provided between the introduction electrode 122 and the opposing electrode 121. Thus, gas G is introduced between the introduction electrode 122 and the opposing electrode 121. As a result, it is possible to suppress noise components such as excess droplets sprayed by the ion source 100 from being introduced into the hole H2 of the introduction electrode 122. The flow rate of gas G is about 0.5 to 50 L / min, and an inert gas such as nitrogen or argon is generally used. In addition, a voltage based on the power supply 500 is applied to the opposing electrode 121 and the introduction electrode 122, but Figure 1 The control lines for the voltage applied to the counter electrode 121 and the lead-in electrode 122 are omitted.

[0062] Ions introduced into the ion source chamber 120 are directed through the aperture H1 provided in the counter electrode 121 toward the aperture H2 provided in the introduction electrode 122. Due to the electric field generated between the ion generating device 110 and the introduction electrode 122, the ions move in the direction of ion generating device 110 → ion source chamber 120 → aperture H1 → aperture H2. Generally, the diameters of aperture H1 provided in the counter electrode 121 and aperture H2 provided in the introduction electrode 122 are approximately several millimeters or less, and the maximum voltage applied to the counter electrode 121 is approximately ± several kV. Furthermore, the voltages applied to the counter electrode 121 and the introduction electrode 122 have the same polarity.

[0063] The ions are then introduced from the hole H2 provided in the introduction electrode 122 through the ion guide 200 and the ion transport device 300 to the mass spectrometer 400, where they are analyzed by the mass spectrometer 400. Various voltages are applied by the power supply 500 to the ion source 100 (ion generating device 110), the ion guide 200, the ion transport device 300, and the mass spectrometer 400. The timing and voltage values ​​of the voltage applied by the power supply 500 are controlled by the control device 600.

[0064] (Ion Guide 200, Ion Transport Device 300)

[0065] like Figure 1 As shown, the interior of the vacuum container 130 is sometimes divided into a plurality of vacuum chambers V1 to V3. The vacuum chamber V1 and the vacuum chamber V2 are connected through a small-diameter hole H3. Furthermore, the vacuum chamber V2 and the vacuum chamber V3 are connected through a small-diameter hole H4. The holes H2, H3, and H4 provided in the introduction electrode 122 are passages for ions. Furthermore, a voltage may be applied to the components having the holes H3 and H4. When a voltage is applied to the components having the holes H3 and H4 (and the hole H2), the housing of the vacuum container 130 and the like are insulated from the components having the holes H3 and H4 (and the hole H2) by an insulator (not shown). Furthermore, the holes H3 and H4 are generally a few mm or less.

[0066] Furthermore, the vacuum chambers V1 to V3 are evacuated by vacuum pumps P1 to P3, respectively. As a result, generally, the vacuum chamber V1 is maintained at several hundred to several thousand Pa, the vacuum chamber V2 is maintained at several Pa, and the vacuum chamber V3 is maintained at approximately 0.1 Pa or less. An ion guide 200 that allows ions to pass through while being bunched is provided in the vacuum chamber V1. An ion transport device 300 that allows ions to pass through while being bunched is provided in the vacuum chamber V2, similarly to the ion guide 200. A multi-pole ion guide 200, an electrostatic lens, an ion funnel, etc. can also be provided in the ion transport device 300. A high-frequency voltage, a direct current voltage, an alternating current voltage, etc. are applied from the power supply 500 to the ion guide 200 and the ion transport device 300, and a voltage obtained by combining these voltages is also applied. In addition, the number of vacuum chambers V1 to V3 is relatively large. Figure 1 In the case of more than the number shown, Figure 1 For example, another vacuum chamber maintained at several hundred Pa may be provided between the vacuum chamber V1 and the vacuum chamber V2, and the vacuum chamber may be provided with a plurality of vacuum chambers. Figure 1 The ion transport device 300 shown is different from the ion transport device 300, etc.

[0067] (Quality Analysis Unit 400)

[0068] The mass spectrometer 400 is composed of an ion separation device 401, a detection device 402, etc. The ion separation device 401 that separates and dissociates ions can use an ion trap, a quadrupole filter electrode, a collision cell, a time-of-flight mass spectrometer (TOF), etc., as well as a structure that combines these. The ions that have passed through the ion separation device 401 are detected by the detection device 402. The detection device 402 can use an electron multiplier tube, a multichannel plate (MCP), etc. The ions detected by the detection device 402 are converted into electrical signals, etc., and the control device 600 can analyze the mass, intensity, and other information of the ions in detail. In addition, the control device 600 is equipped with an input and output unit (not shown) and a memory for accepting user input instructions and controlling voltage, etc., and also has software required for the operation of the power supply 500. The voltage supplied from the power supply 500 to the mass spectrometer 400 can use a high-frequency voltage, a direct current voltage, an alternating current voltage, etc., as well as a voltage that combines these.

[0069] In this embodiment, the longitudinal direction of the ion guide 200 is defined as the X-axis, and axes perpendicular to the X-axis, passing through the center C of the ion guide 200, and perpendicular to each other are defined as the Y-axis and the Z-axis. In particular, the direction from the ion source 100 to the mass spectrometer 400 is defined as the X-axis, the upward direction of the mass spectrometer 1 is defined as the Z-axis, and the direction perpendicular to the X-axis and the Z-axis is defined as the Y-axis.

[0070] (Ion guide 200) (Dodecapole cylindrical rod electrode 20)

[0071] Next, use Figures 2 to 9 The ion guide 200 of this embodiment will be described in detail.

[0072] Figure 2 1 is a diagram showing the structure of an ion guide 200 including twelve (dodecole) cylindrical rod electrodes 20 ( 20 - 1 to 20 - 12 ). In the following description, an ion guide 200 including n rod electrodes 20 is referred to as an n-pole ion guide 200 .

[0073] also, Figure 2 , for simplicity, only the rod electrode 20 is shown.

[0074] Figure 2 In the figure, the left figure Z1 is a figure observed from the entrance side of the ions. In addition, in this embodiment, the entrance side of the ions (or only the entrance side) refers to Figure 1 One side of the ion source 100 is shown. And, Figure 2 The central figure Z2 is a figure of the ion guide 200 viewed from the side. Figure 2In the central diagram Z2 of FIG, only the rod electrodes 20-1 and 20-7 are shown for simplicity. Figure 2 The right figure Z3 is from the exit side of the ion ( Figure 1 In this embodiment, the outlet side (or only the outlet side) of the ion refers to Figure 1 One side of the mass analysis unit 400 is shown.

[0075] like Figure 2 As shown, a plurality of columnar rod electrodes 20 (20-1 to 20-12) are arranged circularly (annularly) with respect to the center C of the ion guide 200. Each rod electrode 20 is arranged to have an angle "θ" in the longitudinal direction. The angle "θ" will be described below.

[0076] and, Figure 3A and Figure 3B It only shows the composition Figure 2 A diagram of one of the rod electrodes 20 ( 20 - 1 ) of the rod electrodes 20 of the ion guide 200 is shown. Figure 3A This is a diagram of the rod electrode 20 viewed from the ion entrance side. Figure 3B This is a diagram of the rod electrode 20 viewed from the ion outlet side.

[0077] like Figure 3A and Figure 3B As shown in FIG. 1 , the rod electrode 20 of this embodiment is characterized in that the cylindrical rod electrode 20 has a concave and arc-shaped recessed portion, i.e., a notch portion 21, on the side surface. Furthermore, a convex portion 26 is provided on the side surface of the rod electrode 20 opposite to the side surface having the notch portion 21. Thus, the notch portion 21 (recessed portion) and the convex portion 26 are provided on the side surface of the rod electrode 20. Furthermore, Figure 3A In FIG. 1 , the shape of the rod electrodes 20-1 to 20-12 without the cutout portion 21 is shown by a single dot chain line. Figure 2 The characteristic of this embodiment is that the ion guide 200 is arranged at an angle "θ" relative to the X-axis. That is, the ion guide 200 of this embodiment is configured so that the diameter is reduced on one side (the outlet side) of the mass spectrometer 1. Furthermore, "θ" is preferably about 10° or less.

[0078] also, Figure 2 In order to avoid complexity, the symbols of the cutout portion 21 and the convex portion 26 are omitted. Figures 2 to 3B As shown, the notch portion 21 of a certain rod electrode 20 is fitted into the protrusion 26 of another rod electrode 20 in a non-contact state.

[0079] Figure 4 : is a diagram showing a top view, a cross-sectional view, and an arrow view of one rod electrode 20 of this embodiment. When the direction in which the cutout portion 21 is provided is set to the upper side of the paper surface of the rod electrode 20, Figure 4 The upper diagram Z4 is a diagram (top view) of the rod electrode 20 as viewed from above. Figure 4 The lower right figure Z5 is an AA cross-sectional view of the rod electrode 20. Figure 4 The lower left figure Z6 is a diagram of the rod electrode 20 as viewed from the arrow B (inclined direction of α°) of the ion guide 200 (view from the arrow B).

[0080] like Figure 4 As shown, the rod electrode 20 is characterized in that a concave cutout portion 21 is formed in an arc of radius "RC" over the entire length of a cylinder of diameter (φ) "D" and length "L". The cutout portion 21 is formed in a state of being inclined at a predetermined angle, i.e., "α°" relative to the longitudinal direction of the rod electrode 20 (set at a predetermined angle). Thus, the cutout portion 21 is provided shallower on the inlet side, and is provided deeper on the outlet side. Thus, the wall thickness of the rod electrode 20 on the inlet side and the outlet side can be changed. As shown Figure 2 As shown, even when twelve rod electrodes 20 are arranged at an angle "θ" relative to the X-axis, the ion guide 200 can be assembled without the rod electrodes 20 contacting each other. In other words, even when the rod electrodes 20 are arranged at an angle, the notch 21 of one rod electrode 20 can be kept in contact with the protrusion 26 of another rod electrode. Preferably, "D" is approximately 10 mm or less, "L" is approximately 100 to 300 mm, and "α°" is approximately 5° or less.

[0081] And, as Figure 4 As shown, in this embodiment, a notch 21 is formed along the entire length of the rod electrode 20 in the form of a circular arc with a constant radius "RC." However, as long as a certain degree of clearance can be maintained between adjacent rod electrodes 20 without contact, the shape of the notch 21 is not limited. As will be explained below, the shape of the notch 21 does not need to be the same throughout its entire length. The ridges 22 formed by the notch 21 can also be chamfered or rounded to prevent discharge, for example.

[0082] and, Figure 2 The size of the gap between adjacent rod electrodes 20 also depends on the applied voltage, but is preferably approximately 0.1 mm to 5 mm. Furthermore, the gap width can be configured to be approximately the same from the inlet side to the outlet side. Alternatively, the gap size can vary from the inlet side to the outlet side. This also applies to the embodiments and modifications described below.

[0083] Figure 5 2 is a perspective view showing four rod electrodes 20-6 to 20-9 among the twelve rod electrodes 20 constituting the ion guide 200. Figures 2 to 4The features of the rod electrode 20 shown in FIG. 1 realize an ion guide 200 in which the radius of the inscribed circle gradually decreases from the inscribed circle 23 of the rod electrode 20 on the inlet side to the inscribed circle 24 of the rod electrode 20 on the outlet side. In other words, in order to make the inscribed circle 23 of the rod electrode 20 on the inlet side larger than the inscribed circle 24 of the rod electrode 20 on the outlet side, the rod electrode 20 is tilted at an angle "θ" (refer to FIG. Figure 2 ) rod electrodes are arranged in a manner similar to rod electrodes. This allows the internal space of the ion guide 200 to gradually narrow toward the outlet. By gradually narrowing the internal space of the ion guide 200, the focusing force of the multipole electric field can be gradually strengthened toward the outlet, allowing ions to gradually converge near the center C. Furthermore, during analysis, an airflow containing droplets, which can cause noise, can be discharged from the gaps between the rod electrodes 20 (i.e., droplets are discharged from the gaps between the rod electrodes 20). This improves the efficiency of separating ions from the airflow containing droplets.

[0084] Next, refer to Figure 6 The gap between adjacent rod electrodes 20 will be described.

[0085] Figure 6 It is a diagram regarding the gap between adjacent rod electrodes 20 .

[0086] For simplicity, Figure 6 Only the rod electrodes 20-1 and 20-2 are shown. The dot-dash line S represents the distances "R1" to "Rn" ( Figure 6 The lines connecting the centers GC1-GCn of the rod gaps GA1-GAn at the respective arcs (shown by dashed lines) are also characterized by the ion guide 200 of this embodiment being that the dot-dash lines S do not lie on a straight line. This relationship may exist over the entire length of each rod electrode 20 or only over a portion of the rod electrode 20 in its longitudinal direction.

[0087] Figure 7 and Figure 8 1 is a diagram showing an example of an ion guide 200 provided with a holder 210 .

[0088] Figure 7 The left figure Z11 is a figure of the ion guide 200 provided with the bracket 210 as viewed from the entrance side. Figure 7 The right figure Z12 is a side view of the ion guide 200 provided with the bracket 210. Figure 8 This is an enlarged view of the rod electrodes 20 - 1 and 20 - 2 . Figure 7 and Figure 8 In, with Figures 2 to 6 The same structures are denoted by the same symbols and their description is omitted.

[0089] In the actual ion guide 200, as Figure 7 As shown, the twelve rod electrodes 20 (20-1 to 20-12) are held by a holder 210 (210a, 210b) made of an insulating material, that is, an insulating member. Figure 7 As shown, the bracket 210 (210a, 210b) has a shape that contacts each rod electrode 20 and is composed of an insulating component. In addition, the bracket 210 can be of any shape as long as it can support the rod electrode 20. As described above, in the ion guide 200 of the present embodiment, the rod electrodes 20-1 to 20-12 are respectively arranged at an angle relative to the X-axis. Therefore, the inner diameters of the bracket 210a and the bracket 210b made of insulating material are different. That is, the inner diameter of the bracket 210a arranged on the inlet side is larger than the inner diameter of the bracket 210b arranged on the outlet side. And, as described above, the notch portion 21 having a concave shape (see Figure 3A 、 Figure 3B The rod electrodes 20-1 to 20-12 are arranged in a tilted state relative to the X-axis. Figure 8 As shown, it is possible to achieve that the contact portions 211a and 211b are not visible when the ion guide 200 is viewed from the entrance side ( Figure 7 The structure of the left figure (the dashed line portion of Figure Z11). Contact portions 211a and 211b are the portions where the holder 210 (210a, 210b) contacts the rod electrode 20. Contact portion 211a is the portion where the holder 210a contacts the rod electrode 20. Similarly, contact portion 211b is the portion where the holder 210b contacts the rod electrode 20.

[0090] The rod electrodes 20 are held by the holder 210, and the ion guide 200 can be installed in the vacuum chamber V1 (see FIG. Figure 1 ).

[0091] In particular, Figure 8 As shown, the insulating edge portions 212a and 212b are not visible when the ion guide 200 is viewed from the entrance side. In addition, the insulating edge portion 212a refers to the portion of the contact portion 211a that corresponds to the gap of the rod electrode 20. Similarly, the insulating edge portion 212b refers to the portion of the contact portion 211b that corresponds to the gap of the rod electrode 20. The structure in which the insulating edge portions 212a and 212b are not visible when the ion guide 200 is viewed from the entrance side can prevent contamination and improve robustness. In addition, in reality, the contact portions 211a and 211b (and the insulating edge portions 212a and 212b) have a width, and Figure 8 Shown as a line.

[0092] Figure 9 It is a diagram showing other explanations of the features of the ion guide 200 according to the first embodiment.

[0093] For simplicity, Figure 9 Only rod electrodes 20-1 to 20-2 are shown. Figure 2 ) of a certain distance "R" ( Figure 9 The line GL connecting the center GC of the rod gap GA at the position of the arc shown by the dotted line and the center C. The present embodiment is characterized in that the adjacent rod electrodes 20 (at Figure 9 In the example shown, the shape of the rod electrodes 20-1 and 20-2 is not line-symmetrical with respect to the line GL near the line GL. This relationship may exist over the entire length of the rod electrode 20 or only in a portion of the longitudinal direction.

[0094] As shown in the first embodiment, the notch 21 of one rod electrode 20 fits in a non-contact state with the protrusion 26 of another rod electrode 20. In the ion guide 200 having such a structure, droplets discharged from the interior of the ion guide 200 to the outside are blocked by the protrusion 26 of the rod electrode 20. As a result, the droplets are less likely to reach the insulating edge portion 212a.

[0095] According to the structure of the ion guide 200 of the present embodiment described above, it is possible to suppress the contamination of the insulating edge portions 212a and 212b of the support 210 by droplets. As a result, the robustness of the ion guide 200 can be improved. Thus, by improving the robustness of the ion guide 200, the holes H1 and H2 can be enlarged (see Figure 1 ) diameter, increasing the amount of ions introduced. This can improve the mass spectrometer 1 (refer to Figure 1 ) analytical sensitivity.

[0096] In addition, the ion guide 200 of this embodiment is configured Figure 1 In addition to the vacuum chamber V1 shown, the arrangement can also be performed in other vacuum chambers such as the vacuum chamber V2.

[0097] Next, refer to Figures 10 to 23 , other embodiments and modifications of the ion guide 200 of this embodiment will be described.

[0098] [Second embodiment] (Cylindrical rod electrode 20a and octupole ion guide 200a)

[0099] Next, refer to Figure 10 A second embodiment will be described.

[0100] Figure 10 This is a diagram showing an ion guide 200 a according to the second embodiment.

[0101] Figure 10 For simplicity, only Figures 2 to 9 The differences of the ion guide 200 shown will be described. Figure 10 , for simplicity, only the rod electrode 20a is shown. Figure 10 The left image Z21 is a view from the ion entrance direction. Figure 10 The central figure Z22 is a side view. Figure 10 In the central figure Z22, for simplicity, only the rod electrodes 20a-1 and 20a-5 are shown. Figure 10 The right figure Z23 is a view observed from the ion outlet side.

[0102] Figure 10 , an ion guide 200a is shown in which eight (octupole) cylindrical rod electrodes 20a having concave shapes and arc-shaped cutouts 21 are arranged in a circle with respect to a center C. The structure of each rod electrode 20a is the same as that of the rod electrode 20 shown in the first embodiment. Figure 10 In the ion guide 200a shown, the notch 21 of a rod electrode 20a is also fitted with the protrusion 26 of another rod electrode 20a in a non-contact state. Figure 10 The ion guide 200a shown is different from the ion guide 200a in that it includes eight cylindrical rod electrodes 20a-1 to 20a-8 (octopole). Figures 2 to 9 The structure of the ion guide 200 shown is different. Figure 10 The basic effect of the ion guide 200a shown is similar to Figures 2 to 9 The examples shown are the same, but the ion focusing efficiency tends to be higher with the octopole than with the dodecapole.

[0103] [Third Embodiment] (Cylindrical Rod Electrode 20b and Hexapole Ion Guide 200b)

[0104] Next, refer to Figure 11 A third embodiment will be described.

[0105] Figure 11 This is a diagram showing an ion guide 200 b according to the third embodiment.

[0106] Figure 11 For simplicity, only Figures 2 to 9 The differences of the ion guide 200 shown are shown. And, for simplicity, Figure 11 Only the rod electrode 20b is shown. Figure 11 The left image Z31 is a view observed from the ion entrance side. Figure 11 The central figure Z32 is a side view. Figure 11 In the central diagram Z32, only the rod electrodes 20b-1 and 20b-4 are shown for simplicity. Figure 11 The right image Z33 is a view observed from the ion exit side.

[0107] Figure 11 , an ion guide 200b is shown in which six (hexapole) cylindrical rod electrodes 20b having concave shapes and arc-shaped cutouts 21 are arranged in a circle with respect to a center C. The structure of each rod electrode 20b is the same as that of the rod electrode 20 shown in the first embodiment. Figure 11 In the ion guide 200b shown, the notch 21 of a rod electrode 20b is also fitted with the protrusion 26 of another rod electrode 20b in a non-contact state. Figure 11 The ion guide 200b shown in the figure is different from the ion guide 200b in that it includes six cylindrical rod electrodes 20b-1 to 20b-6 (hexapole). Figures 2 to 9 The ion guide 200 shown is different. The basic effect of the ion guide 200b is the same as Figures 2 to 9 The ion guide 200 shown, Figure 10 The ion guide 200 a shown is the same, but the ion focusing efficiency of the hexapole tends to be higher than that of the octupole.

[0108] Next, refer to Figures 12 to 17B , modifications of the first embodiment (as well as the second and third embodiments) are described.

[0109] [First Modification] (Approximately Long Columnar Dodecapole Ion Guide 200c)

[0110] Next, refer to Figure 12 、 Figure 13A as well as Figure 13B , the first variant example is described.

[0111] Figure 12 1 is a diagram showing an ion guide 200 c according to a first modification.

[0112] Figure 12 For simplicity, only Figures 2 to 9 The differences between the above-mentioned ion guide 200 and the ion guide 200 are described below. Figure 12 Only the rod electrode 20c is shown. Figure 12 The left image Z41 is from the entrance side of the ion ( Figure 1 ) is observed on the left side of the graph. And, Figure 12 The central figure Z42 is a side view. Figure 12 In the central diagram Z42, only the rod electrodes 20c-1 and 20c-7 are shown for simplicity. Figure 12 The right image Z43 is a view observed from the ion outlet side.

[0113] Figure 12The ion guide 200 c shown has twelve rod electrodes 20 c ( 20 c - 1 to 20 c - 12 ) that are substantially cylindrical (having a substantially oblong cross-sectional shape) and are arranged in a circle with respect to a center C.

[0114] and, Figure 13A and Figure 13B This is a diagram showing only one rod electrode 20 c - 1 among the rod electrodes 20 c constituting the ion guide 200 c . Figure 13A This is a diagram of the rod electrode 20c-1 viewed from the inlet side. Figure 13B The rod electrode 20c-1 is viewed from the outlet side. The first modified example of the rod electrode 20c is characterized in that the substantially long cylindrical rod electrode 20c ( Figure 13A and Figure 13B In the rod electrode 20c-1), a concave and arc-shaped cutout portion 21 is provided. Furthermore, a convex portion 26 is provided on the side of the rod electrode 20c opposite to the side having the cutout portion 21. Figure 13A In FIG. 1 , the shape of the ion guide 200 c without the cutout 21 is shown by a single dot chain line. Figures 2 to 9 The ion guides 200 shown are identical.

[0115] also, Figure 12 In order to avoid complexity, the symbols of the cutout portion 21 and the convex portion 26 are omitted. Figure 12 As shown, the notch portion 21 of a certain rod electrode 20 c is fitted into the protrusion 26 of another rod electrode 20 c in a non-contact state.

[0116] [Second Modification] (Dodecapole Ion Guide 200d Having V-Shaped Notch 21)

[0117] Next, refer to Figure 14 、 Figure 15A as well as Figure 15B , the second variant example is described.

[0118] Figure 14 1 is a diagram showing an ion guide 200 d according to a second modification.

[0119] Figure 14 For simplicity, only Figures 2 to 9 The differences between the ion guide 200 shown in FIG. 2 and FIG. 3 are described below. Figure 14 Only the rod electrode 20d is shown.

[0120] Figure 14 The left image Z51 is a view from the ion entrance side. Figure 14 The central figure Z52 is a side view. Figure 14In the central figure Z52, for simplicity, only the rod electrodes 20d-1 and 20d-7 are shown. Figure 14 The right image Z53 is a view observed from the ion outlet side.

[0121] Figure 14 , the structure of a dodecapole ion guide 200d composed of cylindrical rod electrodes 20d (20d-1 to 20d-12) is shown. Figure 14 In FIG, for simplicity, only the rod electrode 20d is shown.

[0122] Figure 15A and Figure 15B This is a diagram showing only one rod electrode 20d-1 among the rod electrodes 20d constituting the ion guide 200d. Figure 15A This is a diagram of the rod electrode 20d-1 viewed from the inlet side. Figure 15B This is a diagram of the rod electrode 20d-1 viewed from the outlet side.

[0123] like Figure 14 As shown, the rod electrodes 20 d are arranged in a circle with respect to the center C. Figures 14 to 15B The rod electrode 20d of the second modified example shown in FIG. Figure 15A and Figure 15B The rod electrode 20d-1 is characterized in that a concave and V-shaped cutout portion 21 is provided on the cylindrical rod electrode 20d. In addition, a convex portion 26 is provided on the side of the rod electrode 20d opposite to the side having the cutout portion 21. Figure 14 In A, the shape of the ion guide 200d without the cutout 21 is shown by a dashed line. Figures 2 to 9 The ion guides 200 shown are identical.

[0124] also, Figure 14 In order to avoid complexity, the symbols of the cutout portion 21 and the convex portion 26 are omitted. Figure 14 As shown, the notch portion 21 of a certain rod electrode 20 d is fitted into the protrusion 26 of another rod electrode 20 d in a non-contact state.

[0125] [Third Modification] (Dodecapole Ion Guide 200e Having V-Shaped Notch 21 and Prismatic Rod Electrodes 20e)

[0126] Next, refer to Figure 16 、 Figure 17A as well as Figure 17B , the third variant example is described.

[0127] Figure 16 1 is a diagram showing an ion guide 200 e according to a third modification.

[0128] Figure 16 For simplicity, only Figures 2 to 9 The differences of the ion guide 200 shown in FIG. Figure 16 In FIG, for simplicity, only the rod electrode 20e is shown.

[0129] Figure 16 The left image Z61 is a view from the ion entrance side. Figure 16 The central figure Z62 is a figure of the ion guide 200e viewed from the side. Figure 16 In the central figure Z62, for simplicity, only the rod electrodes 20e-1 and 20e-7 are shown. Figure 16 The right image Z63 is a view of the ion guide 200e as viewed from the ion exit side.

[0130] Figure 16 , a dodecapole ion guide 200 e composed of twelve prismatic rod electrodes 20 e ( 20 e - 1 to 20 e - 12 ) is shown.

[0131] and, Figure 17A and Figure 17B This is a diagram showing only one rod electrode 20 e - 1 among the rod electrodes 20 e constituting the ion guide 200 e . Figure 17A This is a diagram of the rod electrode 20e-1 viewed from the inlet side. Figure 17B This is a diagram of the rod electrode 20e-1 viewed from the outlet side.

[0132] like Figure 16 As shown, the rod electrodes 20 e are arranged in a circle with respect to the center C. Figures 16 to 17B The rod electrode 20e of the third modified example shown in FIG. Figure 17A and Figure 17B The rod electrode 20e-1) is characterized in that a concave and V-shaped cutout portion 21 is provided on the prismatic rod electrode 20e. Furthermore, a convex portion 26 is provided on the side of the rod electrode 20e opposite to the side having the cutout portion 21. Figure 17A In FIG. 1 , the shape of the ion guide 200e without the cutout 21 is shown by a single dot chain line. Figures 2 to 9 The ion guides 200 shown are identical.

[0133] also, Figure 16 In order to avoid complexity, the symbols of the cutout portion 21 and the convex portion 26 are omitted. Figure 16 As shown, the notch portion 21 of a certain rod electrode 20 e is fitted into the protrusion 26 of another rod electrode 20 e in a non-contact state.

[0134] [Fourth embodiment] (Notch 21 provided midway)

[0135] Next, refer to Figures 18 to 20 , a fourth embodiment is described.

[0136] In the fourth embodiment, a configuration of a quadrupole ion guide 200 f including a cylindrical rod electrode 20 f having a concave arc-shaped cutout portion 21 provided midway in the longitudinal direction will be described.

[0137] Figure 18 1 is a diagram showing the structure of an ion guide 200 f according to the fourth embodiment.

[0138] Figure 18 For simplicity, only Figures 2 to 9 The differences between the ion guide 200 shown in FIG. 2 and FIG. 3 are described below. Figure 18 Only the rod electrode 20f is shown. Figure 18 The left figure Z71 is a figure of the ion guide 200f observed from the ion entrance side. Figure 18 The central figure Z72 is a figure of the ion guide 200f viewed from the side. Figure 18 In the center diagram Z72, only the rod electrodes 20f-1 and 20f-3 are shown for simplicity. The right diagram Z73 is a diagram of the ion guide 200f as viewed from the ion outlet side.

[0139] Figure 18 , the structure of a quadrupole ion guide 200f is shown in which four cylindrical rod electrodes 20f (20f-1 to 20f-4) are arranged in a circle with respect to a center C. Figure 18 As shown in FIG. 1 , in the ion guide 200 f , a notch 21 having a concave and arc-shaped shape is provided midway in the longitudinal direction of the rod electrode 20 f .

[0140] Figure 19A and Figure 19B This is a diagram showing only one rod electrode 20f-1 among the rod electrodes 20f constituting the ion guide 200f. Figure 19A This is a diagram of the rod electrode 20f-1 viewed from the inlet side. Figure 19B This is a diagram of the rod electrode 20f-1 viewed from the outlet side. Figure 19A and Figure 19B The example shown is a rod electrode 20f-1) characterized in that a concave, arc-shaped cutout 21 is provided midway along the length of the rod electrode 20f. Furthermore, a protrusion 26 is provided on the side surface of the rod electrode 20f opposite to the side surface having the cutout 21.

[0141] Figure 20It is a perspective view showing two rod electrodes 20 f - 3 to 20 f - 4 among the four rod electrodes 20 f constituting the ion guide 200 f .

[0142] exist Figure 20 In the example shown, Figures 2 to 9 Similar to the ion guide 200 shown, the radius of the inscribed circle gradually decreases from the inscribed circle 23f of the rod electrode 20f on the entrance side to the inscribed circle 24f of the rod electrode 20f on the exit side. In the fourth embodiment, a cutout 21 is provided from a starting point 25 located midway along the length of the rod electrode 20f toward the exit side. That is, the cutout 21 is provided in the rod electrode 20f from midway along the length of the rod electrode 20f toward the ion exit side (in the direction of the inscribed circle 24f).

[0143] also, Figure 18 In order to avoid complexity, the symbols of the cutout portion 21 and the convex portion 26 are omitted. Figures 18 to 20 As shown, the notch portion 21 of a certain rod electrode 20 f is fitted into the protrusion 26 of another rod electrode 20 f in a non-contact state.

[0144] In the rod electrode 20f, the support 210 is not provided in the portion where the cutout portion 21 is not provided (see Figure 7 ) Therefore, in the portion where the cutout portion 21 is not provided, contamination of the insulating edge portions 212a and 212b does not occur.

[0145] The basic effects of the ion guide 200f are the same as those of the ion guide 200, but the quadrupole tends to have higher ion focusing efficiency than the hexapole of the third embodiment. In particular, in a configuration where the number of rod electrodes 20f (the number of poles) is reduced, sufficient spacing can be maintained between adjacent rod electrodes 20f even without the cutout 21 on the entrance side. Therefore, as in the fourth embodiment, the cutout 21 can be formed midway along the length of the rod electrodes 20f.

[0146] Furthermore, according to the fourth embodiment, compared with the ion guides 200 and 200a to 200e, the portion cut to form the notch portion 21 can be reduced. Therefore, the cost can be improved.

[0147] (Fifth Embodiment) (Example in which rod electrodes 20g are provided in parallel)

[0148] Reference Figure 21 , the ion guide 200g of the fifth embodiment will be described in detail.

[0149] Figure 21 1 is a diagram showing the structure of a dodecapole ion guide 200 g in which twelve cylindrical rod electrodes 20 g ( 20 g - 1 to 20 g - 12 ) are arranged parallel to the longitudinal direction. Figure 21 For simplicity, only the differences from the ion guide 200 are described. Figure 21 In FIG. 1 , the left image Z81 is a view of the ion guide 200g as viewed from the ion entrance side. Figure 21 In the central diagram Z82, only the rod electrodes 20g-1 and 20g-7 are shown for simplicity. Figure 21 The central figure Z82 is a figure of the ion guide 200g viewed from the side. Figure 21 The right image Z83 is a view of the ion guide 200g as viewed from the ion exit side.

[0150] exist Figure 21 In the ion guide 200g shown, cylindrical rod electrodes 20g-1 to 20g-12 having concave and arc-shaped cutouts 21 are arranged in parallel. Figure 21 The left diagram Z81 and the right diagram Z83 of FIG. 8 show a state in which the rod electrodes 20g are simply inverted with respect to the Z axis.

[0151] like Figure 21 As shown, a protrusion 26 is provided on the side surface of the rod electrode 20g opposite to the side surface provided with the notch 21. The notch 21 of one rod electrode 20g is fitted with the protrusion 26 of another rod electrode 20g in a non-contact state.

[0152] The characteristics of the ion guide 200g shown in the fifth embodiment are the same as those of the Figure 6 The features shown, Figure 9 The features shown are identical to those of the ion guide 200. In addition, Figure 6 The characteristic shown is that the dot-dash line S connecting the centers GC1 to GCn of the rod gaps GA1 to GAn at the same distances R1 to Rn from the center C is not on a straight line. Figure 9 As shown, a line GL connecting the center GC of the rod gap GA at a predetermined distance "R" from the center C of the sub-guide 200g and the center C is defined. Figure 9 The characteristic shown is that the shape of the rod electrode 20 g is not line-symmetrical with respect to the line GL in the vicinity of the line GL.

[0153] Figure 22 1 is a diagram showing an example of an ion guide 200 g provided with a bracket 210 c .

[0154] Figure 22 The left image Z91 is a view of the ion guide 200g provided with the bracket 210c as viewed from the inlet side. Figure 22 The right image Z92 is a side view of the ion guide 200g provided with a bracket 210c.

[0155] And, as Figure 22 As shown in FIG. 1 , in an actual ion guide 200g, a holder 210c made of an insulating material is sometimes provided to hold the twelve rod electrodes 20g (20g-1 to 20g-12). In the fifth embodiment, since the rod electrodes 20g (20g-1 to 20g-12) are arranged parallel to the X axis, the holders 210c on the inlet and outlet sides may also be arranged as shown in FIG. Figure 22 The shown areas have the same shape.

[0156] Ion Guide 200g has Figures 2 to 9 The ion guide 200g has the same effect as that of the ion guide 200 shown in FIG. Moreover, since the rod electrode 20g is not provided at an inclination, the ion guide 200g can be provided more simply than the ion guides 200 and 200a to 200f.

[0157] (Sixth Embodiment) (Ion Guide 200h with Notches 21 on Both Sides of Rod Electrode 20h)

[0158] Figure 23 1 is a cross-sectional view showing an ion guide 200h according to the sixth embodiment.

[0159] Figure 23 For simplicity, only the differences from the ion guide 200 are described.

[0160] In the previous examples, a structure was shown in which a notch 21 was provided on one side of each rod electrode 20, 20a to 20g, near the gap formed between adjacent rod electrodes 20, 20a to 20g. In other words, in the examples so far, the notch 21 was provided only on one side of the rod electrodes 20, 20a to 20g. In contrast, the ion guide 200h shown in the sixth embodiment is composed of rod electrodes 20h (20h-1 to 20h-12). Furthermore, the rod electrodes 20h have concave, arc-shaped notches 21 provided on the side surfaces of two rod electrodes 20h, near the gap formed between adjacent rod electrodes 20h. Furthermore, the ion guide 200h is composed of twelve (dodecopole) cylindrical rod electrodes 20h. In other words, in the sixth embodiment, notches 21 are provided on both sides of each of the rod electrodes 20h that constitute the ion guide 200h. Furthermore, providing the cutout portion 21 on both sides means that the cutout portion 21 and the protrusion 26 are provided on one side surface of the rod electrode 20 h and the cutout portion 21 and the protrusion 26 are also provided on the other side surface.

[0161] exist Figure 23In the example shown, an ion guide 200h is shown in which twelve (dodecopole) cylindrical rod electrodes 20h (20h-1 to 20h-12) are arranged in a circle with respect to a center C. Figure 23 is the YZ plane (refer to Figure 1 、 Figure 5 ) is a cross-sectional view of the ion guide 200h at the position of FIG. As described above, in the vicinity of the gap between the rod electrodes 20h, the rod electrodes 20h located on both sides of the gap between the rod electrodes 20h are provided with arc-shaped cutouts 21. That is, in Figure 23 In the ion guide 200h shown, the notches 21 and the protrusions 26 are provided on both side surfaces of the rod electrode 20h. The notches 21 of one rod electrode 20h and the protrusions 26 of another rod electrode 20h are fitted in a non-contact state.

[0162] As described above, the ion guides 200 and 200 a to 200 h of the respective examples described above can also achieve the above-described effects even if the configuration is a combination of the characteristic elements of the respective ion guides 200 and 200 a to 200 h.

[0163] Hereinafter, the ion guide 200 represents the ion guides 200 and 200 a to 200 h , and the rod electrode 20 represents the rod electrodes 20 and 20 a to 20 h .

[0164] Depending on the number of rod electrodes 20 (the number of poles), there is a tendency for different performance to be exhibited, such as ion acquisition efficiency (higher with a greater number of poles) and ion focusing efficiency (higher with a fewer number of poles). However, the optimal structure of the ion guide 200 may vary depending on the sample being tested, so structures with any number of poles are highly important. Furthermore, the structure of the ion guide 200 may also be a structure consisting of rods with a number other than the quadrupole, hexapole, octupole, and dodecapole shown in the above examples. The number of rod electrodes 20 is limited to an even number. This is because voltages of opposite phases are applied to adjacent rod electrodes 20.

[0165] Furthermore, regarding the mounting of the ion guide 200 composed of a plurality of rod electrodes 20, for example, one method involves screwing an insulating holder 210 to the rod electrodes 20. Alternatively, other fixing methods such as bonding the holder 210 to the rod electrodes 20 may be used. Furthermore, members such as pins may be used to determine the positional relationship between the holder 210 and the rod electrodes 20.

[0166] The rod electrode 20 may also have a shape other than the cylindrical, prism, or roughly elongated cylindrical shape shown in the above examples (e.g., a hexagonal prism). Furthermore, various methods can be used to process the cutout portion 21. Examples include cutting (including machining using multi-axis machining), electrical discharge machining (including wire-cut electrical discharge machining), casting, 3D printing, and plastic molding (adding a metal layer to the surface).

[0167] [Common characteristics]

[0168] Figure 24 1 and 2 are diagrams showing features common to the examples described so far (particularly, the cylindrical rod electrode 20 ).

[0169] Figure 24 In the embodiment, the diameter of the rod electrode 20 (without the cutout portion 21 (refer to Figure 3A and Figure 3B The maximum diameter in the direction of the rod electrodes 20 is defined as "D", and the distance between the centers of adjacent rod electrodes 20 is defined as "P". Figure 24 As shown in FIG. 1 , the characteristic of the ion guide 200 can be said to be the relationship D>P. That is, since “D” is larger than “P”, Figure 24 As shown in FIG. 1 , there is a portion (hatched portion DL) where the rod electrodes 20 overlap. This embodiment is characterized in that the overlapping portion (hatched portion DL) is used as a cutout 21, and a gap is provided between the rod electrodes 20. This relationship may be present over the entire length of the rod electrode 20, or may be as follows: Figures 18 to 20 As shown, a portion in the longitudinal direction has.

[0170] [Summary of the effects]

[0171] Next, refer to Figure 25 ,right Figures 2 to 23 The effects of the ion guides 200 and 200a to 200h shown are summarized.

[0172] Figure 25 Among them, the ion guides 200 and 200a to 200h are represented, and the ion guide 200 is mainly referred to.

[0173] Figure 25 This is a partially enlarged view of the rod electrodes 20 - 1 and 20 - 2 in the rod electrodes 20 constituting the ion guide 200 .

[0174] In the ion guide 200 of this embodiment, the notch 21 of one rod electrode 20 engages with the protrusion 26 of another rod electrode 20 in a non-contact manner. With this structure, the ion guide 200 can achieve a structure in which the contact portion 211a and the insulating edge portion 212a are not visible from the center C. The angle between the two ends of the range connecting the insulating edge portion 212a and the respective straight lines L1 and L2 at the center C is denoted as "β." Furthermore, an obstacle (i.e., the rod electrode 20-1) exists within the range of "β." Therefore, a characteristic of this embodiment is that the insulating edge portion 212a is not visible from the center C.

[0175] And, as Figure 2As shown, since the rod electrode 20 is arranged obliquely, the insulating edge portions 212a and 212b are not visible when the ion guide 200 is viewed from the entrance side (see FIG. Figure 8 ) structure. In addition, in this embodiment, in addition to Figure 2 In addition to the arrangement of the rod electrode 20 being tilted as shown in FIG. Figure 21 The structure shown in FIG. 1 is an ion guide 200 g in which rod electrodes 20 g are arranged in parallel.

[0176] And, even if Figure 21 The structure in which the electrodes 20g are arranged in parallel with the rods as in the ion guide 200g shown in FIG. Figure 25 As shown, the insulation along the surface 212a ( Figure 25 ) structure. In other words, due to this structure, droplets discharged from the interior of the ion guide 200g to the outside are blocked by the protrusion 26 of the rod electrode 20. As a result, droplets are less likely to reach the insulating edge portion 212a. Consequently, contamination of the insulating edge portion 212a by droplets and the like can be suppressed. As with the ion guide 200g, the robustness of the ion guide 200g is improved, thereby enhancing long-term analytical performance and stability.

[0177] [Comparative Example]

[0178] Next, refer to Figures 26 to 29 , a comparative example of this embodiment is described.

[0179] Figure 26 1 is a diagram showing the structure of an ion guide 200 j of a comparative example. Figure 26 The left figure Z101 is a diagram of the ion guide 200j viewed from the ion entrance side, and the right figure Z102 is a cross-sectional view of the ion guide 200j on the Z axis. Figure 26 , for simplicity, only the rod electrode 20j is shown.

[0180] Figure 26 The multipole (in Figure 26 In the example shown, a quadrupole ion guide 200j is used.

[0181] and, Figure 27 2 is a diagram showing the structure of an ion guide 200 j provided with a holder 210 . Figure 27 The left diagram Z111 is a diagram of the ion guide 200 j as viewed from the ion entrance side, and the right diagram Z112 is a cross-sectional view of the ion guide 200 j along the Z axis.

[0182] Figure 26In the process, it is necessary to apply high-frequency voltages of opposite phases to the adjacent rod electrodes 20j. Figure 27 As shown, the rod electrode 20j is mostly held by a holder 210 made of an insulating material. In the YZ plane, the rod electrode 20j is held at the same distance "R1" to "Rn" ( Figure 26 The line connecting the centers GC1 to GCn of the rod gaps GA1 to GAn at the dotted circle is defined as line SA. Figure 26 The illustrated ion guide 200j with multipoles is characterized in that the line SA lies in a straight line.

[0183] And, in Figure 26 In the structure of the ion guide 200j shown, the rod electrodes 20j are arranged parallel to the X-axis direction. Therefore, the relationship between the line SA connecting the centers GC1 to GCn of the rod gaps GA1 to GAn and the line SA is constant along the length direction of the rod electrode 20j. In such a structure, Figure 27 As shown in the left figure Z111, due to the rod gaps GA1 to GAn, the insulating edge portion 212 of the bracket 103 can be seen when the ion guide 200j is viewed from the entrance side. Figure 1 ) generated ions and droplets. Moreover, the ion guide 200j has the following functions: from the rod gaps GA1 to GAn (refer to Figure 26 ) etc. to discharge droplets that cause noise during analysis, and the multipole electric field is used to focus ions only near the center C. In other words, the ion guide 200j has the function of separating the airflow containing droplets from ions.

[0184] Therefore, if Figure 27 As shown, in the gaps GA1 to GAn (refer to Figure 26 ) It can be seen that the structure of the insulating flange 212 of the holder 210 increases the possibility of contamination by liquid droplets. Contamination of the insulating flange 212, which is responsible for insulating the adjacent rod electrode 20j, by liquid droplets degrades insulation performance. This also reduces the voltage that can be applied to the rod electrode 20j. As a result, even when the same voltage as before contamination is applied to the rod electrode 20j, the possibility of discharges occurring in the insulating flange 212 increases. This raises the concern of deteriorating analytical performance and stability.

[0185] Figure 28 1 is a diagram showing the structure of an ion guide 200 k of a comparative example. Figure 28 The left figure Z121 is a diagram of the ion guide 200k viewed from the ion entrance side, and the right figure Z122 is a cross-sectional view of the ion guide 200k on the Z axis. Figure 28, for simplicity, only the rod electrode 20k is shown.

[0186] like Figure 28 As shown, the rod electrode 20 k constituting the ion guide 200 k has a prismatic shape.

[0187] and, Figure 29 1 is a diagram showing the structure of an ion guide 200 k provided with a holder 210 . Figure 29 The left figure Z131 is a diagram of the ion guide 200 k viewed from the ion entrance side, and the right figure Z132 is a cross-sectional view of the ion guide 200 k along the Z axis.

[0188] also, Figure 28 and Figure 29 In, with Figure 26 and Figure 27 The same structures are denoted by the same symbols and their description is omitted.

[0189] In by Figure 28 、 Figure 29 The ion guide 200k composed of the prismatic rod electrodes 20k (20k-1 to 20k-4) shown in FIG. 1 has the same characteristics and problems as those of FIG. Figure 26 and Figure 27 The ion guide 200j shown is identical.

[0190] In order to achieve high sensitivity of the mass spectrometer 1, as described in non-patent document 1 and patent document 1, there is a technology for increasing the number of rod electrodes 20j, 20k (the number of poles) and improving the ion acquisition efficiency. Moreover, in the above technology, the rod electrodes 20j, 20k are arranged obliquely (inclined) along the length direction of the rod electrodes 20j, 20k. In other words, the internal space of the ion guide 200k is gradually narrowed toward the outlet side. In this way, the focusing efficiency of the ions is improved. However, in the above technology, as in the above-mentioned subject, Figure 26 、 Figure 28 The structure shown in FIG1 is that the line SA connecting the centers GC1 to GCn of the gaps GA1 to GAn is on a straight line. Therefore, it is considered that the problem of contamination of the holder 210 cannot be solved. In addition, in order to achieve high sensitivity, the introduction electrode 122 is sometimes enlarged (see FIG1). Figure 1 ) of hole H2 (refer to Figure 1 ) diameter, increasing the amount of ions introduced from the atmosphere. In this case, the amount of droplets introduced into the ion guides 200j and 200k also increases further. Therefore, the contamination problem of the holder 210 may become more significant.

[0191] As described above, according to the ion guides 200 and 200 a to 200 h shown in this embodiment, such contamination of the holder 210 (the insulating edge portions 212 a and 212 b ) can be prevented.

[0192] The present invention is not limited to the above-described embodiments and includes various variations. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention and are not necessarily limited to having all the structures described. Furthermore, a portion of the structure of a certain embodiment can be replaced with a structure of another embodiment, and a structure of another embodiment can be added to a structure of a certain embodiment. Furthermore, with respect to a portion of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0193] Furthermore, the control device 600 and the like may also be implemented in part or in whole by hardware, for example, by designing them using integrated circuits. Furthermore, each of the above-mentioned structures and functions may also be implemented by software by having a processor such as a CPU interpret and execute programs that implement each function. In addition to being stored in an HD (Hard Disk), information such as programs, tables, and files that implement each function may also be stored in a recording device such as a memory, an SSD (Solid State Drive), or a recording medium such as an IC (Integrated Circuit) card, an SD (Secure Digital) card, or a DVD (Digital Versatile Disc).

[0194] Furthermore, in this embodiment, control lines and information lines are shown as lines considered necessary for explanation, and not all control lines and information lines are necessarily shown in the product. In reality, it can be considered that almost all components are connected to each other.

[0195] Explanation of symbols

[0196] 1—Mass spectrometer, 20, 20a to 20h, 20-1 to 20-12, 20a-1 to 20a-8, 20b-1 to 20b-6, 20c-1 to 20c-12, 20e-1 to 20e-12, 20f-1 to 20f-4, 20h-2 to 20h-12, 20g-1 to 20g-12—Rod electrode, 21—Notch (recess), 23—Inscribed circle (entrance side of the rod electrode), 23f—inscribed circle, 24—inscribed circle (inscribed circle of the rod electrode on the outlet side), 24f—inscribed circle, 26—convex portion, 200, 200a~200h—ion guide, 210, 210a~210c—bracket, 211a, 211b—contact portion, 212, 212a, 212b—insulating edge portion, 300—ion transport device, C—center.

Claims

1. An ion guide comprising a plurality of rod electrodes having a circular shape and arranged therein, wherein: Each of the rod electrodes has a concave portion and a convex portion on its side. The recessed portion of one of the rod electrodes is fitted into the raised portion of another of the rod electrodes in a non-contact state.

2. The ion guide according to claim 1, wherein The rod electrode is arranged so that an inscribed circle of the rod electrode on the inlet side is larger than an inscribed circle of the rod electrode on the outlet side, and the recess is formed at a predetermined angle with respect to a longitudinal direction of the rod electrode.

3. The ion guide according to claim 2, characterized in that The recess is provided from a midway of the rod electrode toward an ion outlet side in a longitudinal direction of the rod electrode.

4. The ion guide according to claim 1, wherein The concave portion and the convex portion are provided on both side surfaces of the rod electrode.

5. The ion guide according to claim 1, wherein The plurality of rod electrodes are held by a bracket. The bracket has a shape that contacts the rod electrodes and is made of an insulating member. The ion guide according to claim 1 , wherein: Twelve of the above-mentioned rod electrodes are provided.

7. The ion guide according to claim 1, wherein Eight of the above-mentioned rod electrodes are provided.

8. The ion guide according to claim 1, wherein Six of the above-mentioned rod electrodes are provided.

9. The ion guide according to claim 1, wherein The rod electrode has a cylindrical shape.

10. The ion guide according to claim 1, wherein The recessed portion has an arc shape.

11. A mass spectrometer comprising an ion guide comprising a plurality of columnar rod electrodes arranged in a circular pattern, wherein: The above-mentioned ion guide is composed of: Each of the rod electrodes has a concave portion and a convex portion on its side. The recessed portion of one of the rod electrodes is fitted into the raised portion of another of the rod electrodes in a non-contact state.

Images