Vortex generator and mass spectrometer

Abstract

To generate vortex flow by simple configuration.SOLUTION: A vortex generator includes a plate-like portion 110 which has an opening 111 being a through-hole and has a predetermined thickness, the opening 111 which has a circular cross section perpendicular to the axial direction of the opening 111. The vortex generator further has a first capillary 112 which leads out inside the opening 111, airflow toward a tangential direction of the external form of the opening 111 and an axial direction of opening 111. The first capillary 112 is provided at an angle larger than 0° and less than 90° with respect to the central axis of the opening 111. Furthermore, the predetermined angle is an angle at which the airflow can rotate at least one time inside the opening 111.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to vortex generator and mass spectrometer technology. [Background technology]

[0002] Electrospray is known as a method for ionizing biomolecules and the like contained in a solution in a mass spectrometer. In such an ion source using the electrospray method (electrospray ion source), a swirling flow (vortex flow) is caused to flow from the first aperture side toward the metal probe side, which is known to improve the performance of the mass spectrometer.

[0003] Patent document 1 discloses a vortex gas flow interface for electrospray mass spectrometry comprising: "an electrospray interface device comprising: a transport means for transporting a spray exiting an electrospray needle to a low pressure region, the transport means having an inlet for receiving the spray; a source of heated gas; a means for applying centrifugal force to the spray, the means having a structure for forming a vortex gas flow from the heated gas having a velocity component approximately transverse to an inlet of a mass spectrometer and a velocity component opposite to the direction of transport of the spray by the transport means; and an outlet for supplying the formed product of the interface device to the inlet of the mass spectrometer" (see claim 1).

[0004] Patent Document 2 and Non-Patent Document 1 describe a configuration in which an inert gas is introduced into a spiral groove to generate a vortex flow from the mass spectrometer side toward the metal probe side (see Figures 1 and 2 of Patent Document 2).

[0005] Patent Document 3 describes the generation of a vortex by introducing an airflow from a direction inscribed in a conical structure. In this case, a configuration is described in which the vortex flows from the ion source side toward the mass analysis section side while gradually decreasing the diameter of the cone (see FIG. 1 and FIG. 2). With such a structure, the charged droplets introduced into the vortex have a relatively large angular velocity and a relatively small axial velocity of the cone. Therefore, the charged droplets are sufficiently dried by staying in the conical structure for a long time (see column 5, lines 60 to 66). In addition, since the diameter of the conical structure becomes smaller toward the mass analyzer side, ions resulting from the drying of the charged droplets can be converged toward the outlet (see column 6, lines 34 to 37). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4657451 Specification [Patent Document 2] Chinese Patent No. 110112051 [Patent Document 3] U.S. Patent No. 7,595,487 [Non-patent literature]

[0007] [Non-Patent Document 1] Yuze Li, Lingwei Meng, Guanghui Wang, Xiaoyu Zhou, Zheng Ouyang, and Zongxiu Nie, “A Gas-phase Reaction Accelerator using vortex flow” Analytical Chemistry(US),2020,Vol.92,p.12049 Summary of the Invention [Problem to be solved by the invention]

[0008] As described above, it is known that the performance of a mass spectrometer can be improved by passing a spiral swirling flow (vortex flow) from the first aperture side toward the metal probe side. However, in the techniques described in Patent Documents 1 to 3 and Non-Patent Document 1, the structure of the member that generates the vortex flow is complicated, for example, a helical groove is provided in the member placed in front of the first aperture to generate the vortex flow. This causes an increase in costs.

[0009] The present invention has been made in view of the above background, and an object of the present invention is to generate a vortex flow with a simple configuration. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the present invention provides a plate-like portion which is a plate-like member having a predetermined thickness and an opening which is a through hole, and the opening has a circular cross section perpendicular to the axial direction of the opening, and inside the opening, there is an outlet portion which outlets an airflow in a tangent direction to the outer shape of the opening and in the axial direction of the opening. Other solutions will be described in the embodiments as appropriate. Effect of the Invention

[0011] According to the present invention, a vortex flow can be generated with a simple configuration. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a front view of a vortex generating device according to a first embodiment. [Diagram 2] 1 is a diagram showing a vortex generating device according to a first embodiment as viewed from above. [Diagram 3] FIG. 13 is a view showing the opening portion developed in the circumferential direction. [Figure 4] FIG. 13 is a diagram showing the results of a fluid calculation showing the airflow at an opening. [Diagram 5] FIG. 2 is a diagram showing the location of a vortex generator in a mass spectrometer. [Figure 6]FIG. 13 is a diagram showing the relationship between the gas flow rate and the signal intensity detected by a mass spectrometer. [Figure 7] FIG. 13 is a diagram showing the relationship between the exhaust flow rate and the signal intensity when exhaust is performed through the second capillary. [Figure 8] FIG. 11 is a front view of a vortex generating device according to a second embodiment. [Figure 9] FIG. 11 is a top view of a vortex generating device according to a second embodiment. [Figure 10] FIG. 11 is a diagram showing a vortex generating device according to another example of the second embodiment. [Figure 11] FIG. 11 is a first view of a vortex generating device according to a third embodiment, seen from above. [Figure 12] FIG. 13 is a second top view of the vortex generating device according to the third embodiment. [Figure 13] FIG. 1 is a diagram showing an example of a mass spectrometer using a commonly used ion source. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Next, a mode for carrying out the present invention (referred to as an "embodiment") will be described in detail with reference to the drawings as appropriate. In this embodiment, the dimensions of the parts are described for reference, but are not limited to the dimensions described in this embodiment. In addition, the z-axis direction shown in FIG. 1 is appropriately referred to as the up-down direction, and the x-axis direction is appropriately referred to as the left-right direction. Furthermore, the y-axis direction shown in FIG. 2 is appropriately referred to as the depth direction. In addition, the positive side of the z-axis shown in FIG. 1 is referred to as the upper side, and the negative side is referred to as the lower side. The positive side of the x-axis shown in FIGS. 1 and 2 is referred to as the right side, and the negative side is referred to as the left side. Furthermore, the positive side of the y-axis shown in FIG. 2 is referred to as the back side, and the negative side is referred to as the front side. The back side is the side of the first fine hole 301 (see FIG. 5), and the front side is the side of the metal probe 201 (see FIG. 5).

[0014] [First embodiment] FIG. 1 is a view of the vortex current generating device 100 according to the first embodiment as viewed from the front (i.e., from the metal probe 201 side toward the first fine hole 301 side). FIG. 2 is a view of the vortex current generating device 100 according to the first embodiment as viewed from above. In FIG. 1, the front side is the metal probe 201 side. In FIG. 2, the lower side of the paper is the metal probe 201 side, and the upper side of the paper is the first fine hole 301 side. Note that the insulating part 122 and the heater 121 are omitted in FIG. 2.

[0015] The vortex generator 100 includes a plate-shaped portion 110 , a first capillary tube 112 , a second capillary tube 113 , a heater 121 , and an insulating portion 122 . The plate-shaped part 110 is a plate-shaped member having an opening 111 which is a through hole and a predetermined thickness. In the example shown in FIG. 1 and FIG. 2, the plate-shaped part 110 is, for example, a plate-shaped member having a length and width of 20 mm and made of a conductive material. The opening 111 is provided in the center of the plate-shaped part 110, and has a circular cross section perpendicular to the axial direction of the opening 111. The opening 111 need only be located at a position where ions N (see FIG. 5) can be introduced into the first pore 301 (see FIG. 5), and does not necessarily have to be located in the center of the plate-shaped part 110. In the example shown in FIG. 1 and FIG. 2, the diameter of the opening 111 is 5 mm. In the example shown in FIG. 1 and FIG. 2, the length of the cylindrical opening 111 of the vortex generator 100, i.e., the thickness of the plate-shaped part 110, is 5 mm.

[0016] Although the plate-like portion 110 shown in the first embodiment is made of metal, specifically stainless steel, it may be made of any conductive material.

[0017] Furthermore, the vortex generator 100 is provided with a first capillary tube 112 which is an outlet section. The first capillary tube 112 enters the inside of the plate-shaped section 110 at a position a1 from the outside of the plate-shaped section 110, and its end opens at a position a2 of the opening 111. At this time, the first capillary tube 112 outlets the airflow F1 in the tangential direction of the outer shape of the opening 111 and in the axial direction of the opening 111 inside the opening 111. Specifically, the first capillary tube 112 outlets the airflow F1 in the inside of the opening 111 from the side of the first capillary tube 301 (FIG. 5) which is a capillary hole toward the side of the metal probe 201 (see FIG. 5). In FIGS. 1 and 2, the outline arrow A11 indicates the gas introduced into the first capillary tube 112.

[0018] In this manner, the airflow F1 is ejected (guided) from the first capillary tube 112 into the opening 111. The ejected airflow F1 may be compressed air, dry air, nitrogen, a rare gas, or the like. Since the first capillary tube 112 is open at the position a2 under the above-mentioned conditions, the ejected airflow F1 swirls along the inner wall surface of the opening 111 from the back side to the front side. This generates a vortex flow F flowing from the back side to the front side inside the opening 111. The gas is sent to the first capillary tube 112 by a pump (not shown). The diameter of the first capillary tube 112 is, for example, an inner diameter of 0.5 mm and an outer diameter of 0.8 mm.

[0019] In addition, the opening 111 of the vortex generator 100 is opened at the end of the second capillary tube 113, which is a suction section. The second capillary tube 113 sucks the airflow F1 that is led out (ejected). This causes the surplus gas in the vortex flow F to be exhausted. The exhaust of the surplus gas by the second capillary tube 113 makes it possible to stabilize the airflow near the outlet side (the side of the metal probe 201) of the vortex flow F outside the opening 111. Without the exhaust of the surplus gas by the second capillary tube 113, the vortex flow F discharged from the opening 111 and the airflow sent from the metal probe 201 collide with each other, causing turbulence. The exhaust of the surplus gas by the second capillary tube 113 will be described later. The second capillary tube 113 can be omitted. The exhaust of the surplus gas by the second capillary tube 113 is performed by an exhaust pump (not shown). 1 and 2, the outline arrow A12 indicates the gas discharged from the second capillary 113. As shown in FIG.

[0020] As shown in FIG. 2, the end (position a2) of the first capillary tube 112 opens on the side (rear side) of the first orifice 301 of the opening 111. The end of the second capillary tube 113 opens on the side (front side) of the metal probe 201 of the opening 111. As shown in the example of FIG. 2, the first capillary tube 112 is provided in the opening 111 from the side (rear side) of the first orifice 301 toward the side (front side) of the metal probe 201. Furthermore, the (end) of the first capillary tube 112 is provided at an angle of 5° with respect to the surface of the plate-like part 110 on the side of the first orifice 301. In other words, the end of the first capillary tube 112 (the direction in which the airflow F is ejected by the first capillary tube 112) opens at a predetermined angle (85° in the example of FIG. 1) with respect to the central axis 151 of the opening 111. By opening the first capillary 112 under such conditions, the vortex F advances from the first fine hole 301 side (rear side) toward the metal probe 201 side (front side). The angle of the opening 111 of the first capillary 112 with respect to the surface of the plate-like portion 110 on the side of the first fine hole 301 is an example. The angle between the opening 111 of the first capillary 112 and the surface of the plate-like portion 110 on the side of the first fine hole 301 is determined by the thickness of the plate-like portion 110, the diameter of the opening 111, and the like. The first capillary 112 (outlet portion) at the position a2 (the direction of the airflow F1 from the first capillary 112) may be provided at an angle (predetermined angle) greater than 0° and less than 90° with respect to the central axis 151 of the opening 111. The line extending from first aperture 301 toward metal probe 201 with respect to central axis 151 is defined as 0°.

[0021] A heater 121, which is a heating unit, is attached around the plate-shaped portion 110 via an insulating portion 122. The heater 121 heats the plate-shaped portion 110 to a predetermined temperature (for example, 200° C.). The plate-shaped portion 110 is heated by the heater 121, whereby the airflow F1 (vortex flow F) formed in the opening 111 is heated. The effect of heating by the heater 121 will be described later. In addition, a voltage is applied to the plate-shaped portion 110 during analysis by the mass spectrometer 1, which will be described in detail later. By providing the insulating portion 122 between the plate-shaped portion 110 and the heater 121, it is possible to protect the heater 121 from the effects of the voltage applied to the plate-shaped portion 110.

[0022] In the example shown in FIG. 1, the insulating part 122 and the heater 121 are provided on the upper and lower sides of the plate-shaped part 110. However, the location where the insulating part 122 and the heater 121 are provided is not limited to the upper and lower sides of the plate-shaped part 110, as long as the plate-shaped part 110 can be heated and the configuration of the vortex generator 100 is not hindered. For example, the insulating part 122 and the heater 121 may be provided on the left and right sides of the plate-shaped part 110, or the insulating part 122 and the heater 121 may be provided on the back and front sides of the plate-shaped part 110. In this way, the heater 121 is provided on the plate-shaped part 110 via the insulating part. Note that when the insulating part 122 and the heater 121 are provided on the back and front sides of the plate-shaped part 110, the insulating part 122 and the heater 121 are provided with openings 111 having a diameter equal to or larger than the diameter of the openings 111 provided in the plate-shaped part 110.

[0023] Although the heater 121 and the insulating part 122 may be provided only on the upper side or the lower side of the plate-shaped part 110, the vortex generator 100 can be heated more uniformly if the heater 121 is provided on the upper and lower sides of the plate-shaped part 110. The same applies when the heater 121 is provided on the left and right sides or on the rear and front sides of the plate-shaped part 110.

[0024] In addition, the first capillary 112 itself is heated by the heater 141, which is a heating unit. As a result, the airflow F1 (vortex flow F) flowing inside the first capillary 112 is heated.

[0025] (Flow of airflow F1 at opening 111) 3 is a diagram showing the opening 111 expanded in the circumferential direction starting from positions b1 and b2, with reference to FIGS. As shown in Figs. 1 and 2, the airflow F1 ejected through the first capillary tube 112 generates a vortex F at the opening 111 of the vortex generator 100. The vortex F flows from the first orifice 301 side toward the metal probe 201 side. In the following, in order to clarify the positional relationship, a line is defined that passes through the position a2 where the end of the first capillary tube 112 is open, runs along the wall surface of the opening 111, and is parallel to the axial direction of the opening 111. As shown in Fig. 2, the end position of this line on the first orifice 301 side is defined as position b1, and the end position on the metal probe 201 side is defined as position b2. Fig. 3 shows a development of the opening 111 cut open along the line connecting positions b1 and b2. 3, line L11 and line L12 indicate the same location, and line L21 indicates the circumference of opening 111. In the example shown in FIG 3, the circumference of opening 111 is about 15.7 mm.

[0026] In FIG. 3, the solid arrow A1 indicates the direction of the airflow F1 along the wall surface of the opening 111. As described above, the first capillary 112 is open at the position a2 of the cylindrical opening 111 at a position a1 of the vortex generator 100, at an angle of 5° with respect to the surface of the first hole 301 side of the plate-shaped part 110. The airflow F1 ejected from the first capillary 112 flows along the wall surface of the opening 111 to form a vortex flow F. Incidentally, one end and the other end of the dashed line DL in FIG. 3 indicate the same place on the wall surface of the opening 111. In the example shown in FIG. 3, it can be seen that the airflow F1 ejected from the position a2 rotates approximately three times inside the cylindrical opening 111. However, the airflow F1 rotating three times inside the opening 111 is just an example. How many times the airflow F1 rotates inside the opening 111 depends on the dimensions of the opening 111, such as the diameter and length of the opening 111, and the angle at which the first capillary tube 112 is attached. However, the airflow F1 rotates at least one time. In other words, the predetermined angle at which the first capillary tube 112 is installed at position a1 is an angle at which the airflow F1 can rotate at least one time inside the opening 111. Incidentally, as the predetermined angle becomes larger (as the angle becomes deeper), the number of times the airflow F1 can rotate decreases.

[0027] If the airflow F1 rotates less than one revolution inside the opening 111, the airflow F1 becomes uneven (dense and sparse) inside the opening 111. That is, a strong airflow F1 is generated on one part of the wall surface of the opening 111, but the airflow F1 on the other wall surface becomes weak. This results in a decrease in the ions N that reach the first pore 301. By rotating the airflow F1 one or more revolutions inside the opening 111, it is possible to prevent such unevenness (dense and sparse) of the airflow F1, and the ions N can reach the first pore 301.

[0028] (Fluid calculation results) 4 is a diagram showing the result of a fluid calculation, illustrating the flow of the airflow F1 (vortex flow F) at the opening 111. Note that exhaust by the second capillary 113 is omitted in FIG. 4, airflow F1 enters from position a1 by first capillary 112 and is ejected into opening 111 at position a2. Since airflow F1 spreads radially when ejected, as shown in Fig. 4, it can be seen that airflow F1 forms a vortex F and rotates multiple times until it reaches position b2, which is the outlet side of opening 111, although it is not as simple as shown in Fig. 3. Positions b1 and b2 are positions b1 and b2 shown in Fig. 2.

[0029] [Arrangement of vortex generator 100] Fig. 5 is a diagram showing the installation location of the vortex generator 100 in the mass spectrometer 1. Fig. 1 will be referred to as appropriate. FIG. 5 shows the periphery of the ion source 2 of the mass spectrometer 1. Around the ion source 2, the ion source 2, the vortex generator 100, the counter electrode 300, and the electrode 400 with the second orifice 401 opening therein are provided. In this embodiment, the ion source 2 refers to an electrospray ion source. The counter electrode 300 has a first orifice 301 opening therein. The first orifice 301 is a orifice for taking in the ions N generated from the charged droplets Q into a vacuum. The second orifice 401 is provided in the pressure reducing section 4. In addition, a mass spectrometry section 510 (see FIG. 13) for performing mass spectrometry on the ions N taken in from the first orifice 301 (and the second orifice 401) is provided downstream of the pressure reducing section 4, but is omitted in FIG. 5.

[0030] The ion source 2 is equipped with a metal probe 201 that sprays the sample solution LQ. In addition, depending on the flow rate and composition of the sample solution LQ, the ion source 2 may be configured as a double pipe by providing an assist flow piping 202 on the outside of the metal probe 201. In such a configuration, an assist flow airflow F11, which is an airflow for assisting spraying, may be used between the metal probe 201 and the assist flow piping 202. In the example shown in FIG. 5, the assist flow airflow F11 is used. A vortex generator 100 is provided between the metal probe 201 and the first fine hole 301.

[0031] Furthermore, the metal probe 201 is disposed at an angle from the opening 111 of the vortex generator 100 and the central axis of the first fine hole 301. By disposing the metal probe 201 at an angle from the opening 111 and the first fine hole 301 in this manner, large droplets present in large numbers in the center of the spray are prevented from reaching the first fine hole 301. This makes it possible to reduce contamination in the vicinity of the first fine hole 301. Furthermore, in the example shown in Fig. 5, the vortex generator 100 and the first fine hole 301 are disposed at a distance of about 1 mm, but they do not have to be disposed at this distance.

[0032] The droplets sprayed from the metal probe 201 have the property that larger droplets exist in the center and smaller droplets exist on the periphery. By positioning the metal probe 201 at an angle to the opening 111 of the vortex generator 100, the larger droplets located in the center of the spray reach a location away from the opening 111. In contrast, the smaller droplets located on the periphery of the spray reach the opening 111.

[0033] Also, a high voltage is applied between the metal probe 201 and the vortex generator 100. This enables electrostatic spraying of the sample solution LQ. The sample solution LQ is sprayed by the metal probe 201, and the resulting charged droplets Q are introduced into the opening 111. In this way, the sample solution LQ is introduced into the metal probe 201, and a high voltage is applied to the metal probe 201, so that the sample solution LQ is sprayed as charged droplets Q. The charged droplets Q are then exposed to the airflow F1 that forms the vortex F inside the opening 111, and are dried. As a result of the drying, ions N are generated from the charged droplets Q, and the generated ions N move in the order of the opening 111, first pore 301, and second pore 401.

[0034] Furthermore, during mass analysis, a voltage (DC voltage) is also applied between the vortex generator 100 and the counter electrode 300 in which the first aperture 301 is opened. This causes the ions N to drift toward the first aperture 301 inside the opening 111, making it easier for the ions N to pass through the first aperture 301. For example, when measuring positive ions, 4 kV is applied to the metal probe 201, 1 kV to the plate-shaped part 110 of the vortex generator 100, 24 V to the counter electrode 300, and 5 V to the electrode 400 in which the second aperture 401 is opened. Voltages are applied by power sources 601 to 604 to the metal probe 201, the vortex generator 100 (plate-shaped part 110), the counter electrode 300, and the electrode 400 in which the second aperture 401 is opened. In this manner, voltages are applied to the metal probe 201, the plate-like portion 110 of the vortex generator 100, and the counter electrode 300, which is an electrode in which the first fine hole 301 is provided. This voltage is applied so that the ions N based on the charged droplets Q sprayed from the metal probe 201 move toward the first fine hole 301. The application of voltages by the power sources 501 to 504 is controlled by a control device (not shown). When negative ions are measured, the polarities of the voltages applied to the metal probe 201, the vortex generator 100, the counter electrode 300, and the electrode 400 in which the second fine hole 401 is opened are reversed from those when positive ions are measured. In this manner, the ions N can be moved from the opening 111 to the mass analysis section 510 (see FIG. 13).

[0035] As shown in FIG. 1, the vortex generator 100 and the first capillary tube 112 are heated by the heaters 121 and 141, so that the airflow F1 (vortex F) generated inside the opening 111 of the vortex generator 100 is heated. In FIG. 5, the heaters 121 and 141 and the insulating part 122 are omitted. In this way, the charged droplets Q introduced inside the opening 111 are exposed to the heated airflow F1 (vortex F). As a result, the drying of the charged droplets Q is promoted as described above. At this time, if there is a gap between the counter electrode 300 and the vortex generator 100, outside air will flow in through the gap, and the temperature of the airflow F1 will drop.

[0036] In order to prevent such a decrease in temperature of the airflow F1, the mass spectrometer 1 shown in Fig. 5 is provided with an interposed portion 131 between the vortex generator 100 and the counter electrode 300. The interposed portion 131 seals the space between the first aperture 301 and the vortex generator 100. In the example shown in Fig. 5, the interposed portion 131 has a size similar to that of the vortex generator 100 and has a hollow cubic shape. The interposed portion 131 seals the space between the ion outlet side of the vortex generator 100 and the ion inlet side of the first aperture 301.

[0037] However, the interposed portion 131 may have a configuration that does not allow outside air to flow in through the gap between the vortex generator 100 and the counter electrode 300. For example, the interposed portion 131 may be solid except for the portion corresponding to the counter electrode 300, the opening 111, and the hole communicating with the first pore 301. When the temperature of the first capillary 112 is about 200°C, the provision of the interposed portion 131 makes it possible to maintain the temperature of the airflow F1 at about 100°C.

[0038] As described above, different voltages are applied to the vortex generator 100 (plate-like portion 110) and the counter electrode 300 during mass spectrometry, and therefore the interposed portion 131 is made of an insulating material.

[0039] In FIG. 5, the diameter of first pore 301 and the diameter of opening 111 are approximately the same, but in reality, the diameter of first pore 301 is approximately 0.2 mm, while the diameter of opening 111 is approximately 5 mm, as described above.

[0040] (Relationship between air flow rate and signal strength) Fig. 6 is a diagram showing the relationship between the air flow rate and the signal intensity detected by the mass spectrometer 1 when the vortex generator 100 according to the first embodiment is used. Figs. 1 and 5 are referred to as appropriate. Figs. 6 and 7 show the results when amino acids are used as samples. The signal intensity is the intensity of the detection signal detected by the mass spectrometer 1. In Fig. 6, the horizontal axis indicates the flow rate (airflow rate) of the airflow F1 ejected from the first capillary 112, and the vertical axis indicates the signal intensity. Also in Fig. 6, the white circles indicate the average value of the signal intensity, and the error bars indicate the standard deviation of the fluctuation of the signal intensity. The sizes of the components of the vortex generator 100 used in the experiment in Fig. 6 (component sizes) are as shown in Figs. 1 to 3.

[0041] When the airflow F1 is ejected from the first capillary 112 and a vortex F is generated at the opening 111 of the vortex generator 100, the charged droplets Q hit the vortex F and are dried. This improves the efficiency of generating gas-phase ions N, and the ions N are converged by the effect of the vortex F, so that the signal intensity of the mass spectrometer 1 increases. The gas-phase ions N refer to ions N floating in the air. As shown in FIG. 6, in the vortex generator 100 having the component sizes shown in FIGS. 1 to 3, the strongest signal intensity was obtained when the airflow rate was about 1 L / min. In other words, the sensitivity was improved.

[0042] (Relationship between exhaust flow rate and signal strength) 7 is a diagram showing the relationship between the exhaust flow rate and the signal intensity when exhaust is performed by the second capillary 113. FIGS. 1 and 5 will be referred to as appropriate. In FIG. 7, the flow rate (airflow rate) of the airflow F1 ejected from the first capillary 112 to the opening 111 is set to 1 L / min. In addition, the relationship between the exhaust flow rate and the signal intensity detected by the mass spectrometer 1 when a part of the airflow F1 is exhausted from the second capillary 113 is shown. As shown in FIG. 7, even if the exhaust flow rate increases, the signal intensity detected by the mass spectrometer 1 does not change much. However, according to FIG. 7, when the exhaust flow rate is an appropriate flow rate (0.6 L / min in the example shown in FIG. 7), it can be seen that the fluctuation in the signal intensity is suppressed. At any airflow rate other than the appropriate one (0.6 L / min in the example shown in FIG. 7), the vortex F generated in the opening 111 of the vortex generator 100 becomes turbulent when ejected to the outside of the opening 111 (to the side of the metal probe 201). It is believed that at air flow rates other than an appropriate value (0.6 L / min in the example shown in FIG. 7), the generated turbulence disrupts the air flow between the vortex generator 100 and the ion source 2, resulting in large fluctuations in signal intensity.

[0043] 1 and 2, at the opening 111, excess airflow F1 is exhausted from the second capillary 113 opening on the side of the metal probe 201. This makes it possible to reduce turbulence near the outlet side (the side of the metal probe 201) of the opening 111. As a result, the airflow between the vortex generator 100 and the metal probe 201 is stabilized, and fluctuations in the signal intensity of the ions detected by the mass spectrometer 1 are suppressed.

[0044] In the vortex generating device 100 shown in the first embodiment, an opening 111 which is a circular through-hole is provided in a plate-like member 110, and a vortex F is generated by ejecting an airflow F1 at an angle from the opening 111.

[0045] According to the first embodiment, it is possible to generate a vortex F from the first aperture 301 side of the mass spectrometer 1 toward the metal probe 201 side with a simple structure, without processing a complicated structure such as a spiral groove. It has been confirmed that the effect of the vortex F improves the sensitivity of the mass spectrometer 1. This makes it possible to provide a highly sensitive ion source 2 and mass spectrometer 1 at low cost.

[0046] In addition, by generating the vortex flow F, it is possible to remove the large charged droplets Q by centrifugal force and extract only the small charged droplets Q. This makes it possible to improve the analytical accuracy of the mass spectrometer 1.

[0047] [Second embodiment] In the first embodiment, the vortex generating device 100 has been described in detail, but the present invention is not limited to the first embodiment and various modifications are possible. With reference to Figures 8 to 10, vortex flow generators 100a and 100b according to a second embodiment of the present invention are shown. In the vortex flow generators 100a and 100b shown in Figures 8 to 10, a third capillary 112a is provided in order to supply air from a plurality of locations at an opening 111 to generate a vortex flow F. In the second embodiment, an example is shown in which a plurality of first capillary tubes 112 (two in Figures 8 to 10) serving as outlet portions are provided.

[0048] 8 and 9 are diagrams showing the configuration of a vortex current generating device 100a used in the second embodiment. FIG. 8 is a diagram showing the vortex current generating device 100a according to the second embodiment as seen from the front. In FIG. 8, the front side is the side of the metal probe 201. Also, FIG. 9 is a diagram showing the vortex current generating device 100a according to the second embodiment as seen from above. In FIG. 9, the lower side of the paper surface shows the side of the metal probe 201, and the upper side shows the side of the first fine hole 301. Also, in FIGS. 8 to 10, the heater 121 and the insulating part 122 shown in FIG. 1 are omitted. In FIGS. 8 to 10, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted.

[0049] The end of the first capillary 112 is open at a position inscribed in the opening 111, as in FIG. 1. Also, as shown in FIG. 8, the end of the third capillary 112a, which is the lead-out part, is also open at a position inscribed in the cylinder of the opening 111. However, as shown in FIG. 8 and FIG. 9, the end of the first capillary 112 and the end of the third capillary 112a are open at different positions. Also, in the example shown in FIG. 8 and FIG. 9, the position where the third capillary 112a opens is disposed at a position opposite to the position where the first capillary 112 opens. Also, as shown in FIG. 9, both the first capillary 112 and the third capillary 112a are provided on the side of the first capillary 301 (the positive side of the y-axis). Furthermore, as shown in FIG. 9, the third capillary 112a opens at an angle from the side of the first capillary 301 toward the side of the metal probe 201. Inside the opening 111 of the vortex generating device 100a, the airflows F1a and F1b ejected through the first capillary 112 and the third capillary 112a each generate a vortex F. The airflows F1a and F1b flow generally from the first capillary 301 side toward the metal probe 201 side. In addition, in Figs. 8 to 10, the outline arrow A13 indicates the gas introduced into the third capillary 112a.

[0050] In the example shown in FIG. 8 and FIG. 9, the airflow F1a ejected from the first capillary 112 and the airflow F1b ejected from the third capillary 112a form a double-spiral vortex F. The double-spiral vortex F formed by the airflow F1a and the airflow F1b flows inside the opening 111 from the first aperture 301 side to the metal probe 201 side. In this way, the double-spiral vortex F can reduce the bias of the airflow F1 (see FIG. 1) near the wall surface of the opening 111. In other words, if there is only one vortex F, the density of the airflow F1 is biased, but by the double-spiral vortex F, the sparse portion of the airflow F1 due to one airflow F1a is compensated for by the other airflow F1b. This can reduce the bias of the airflow F1 near the wall surface of the opening 111. As a result, the charged droplets Q can be converged to the center of the opening 111 by the vortex generating device 100 shown in the first embodiment.

[0051] In this manner, in the vortex generating device 100a, the air flows F1a and F1b are discharged (ejected) from the first capillary tube 112 and the third capillary tube 112a, respectively. The first capillary tube 112 and the third capillary tube 112a are provided so that the air flows F1a and F1b form a spiral shape with respect to each other and flow through the opening 111.

[0052] FIG. 10 is a diagram showing a vortex generator 100b which is another example of the second embodiment. In the example shown in FIG. 10, the end of the third capillary 112a is opened so that the airflow F1c ejected from the third capillary 112a, which is another outlet portion, is aligned with the airflow F1 ejected from the first capillary 112, which is a predetermined outlet portion. With this configuration, the airflow F1 ejected from the first capillary 112 is urged by the airflow F1c ejected from the third capillary 112a. That is, the first capillary 112 and the third capillary 112a are provided so that the airflow F1 ejected from the predetermined outlet portion (the first capillary 112 in the example of FIG. 10) is urged by the airflow F1c ejected from the other outlet portion (the third capillary 112a in the example of FIG. 10). This strengthens the centrifugal force of the vortex F, making it possible to remove large charged droplets Q by the centrifugal force. This allows stable mass spectrometry results to be obtained.

[0053] In the example shown in Figs. 8 to 10, two thin tubes are provided for ejecting the airflow F1 (see Fig. 10), but three or more may be provided.

[0054] In the second embodiment, air is sent from a plurality of locations inside the opening 111 of the vortex generator 100. The vortex generator 100a shown in Figs. 8 and 9 can generate vortex flows F in a well-balanced manner, and can make the vortex flows F more uniform than the vortex generator 100 shown in the first embodiment. This reduces the bias of the air flows F1a and F1b inside the opening 111, and suppresses fluctuations in the signal intensity of the ions N detected by the mass spectrometer 1. In addition, the vortex generator 100c shown in Fig. 10 can energize the vortex flows F inside the opening 11. As a result, as described above, the centrifugal force of the vortex flows F can be used to remove large charged droplets Q, and stable mass analysis results can be obtained.

[0055] 8 to 10, a second capillary tube 113 is provided on the side of the opening 111 facing the metal probe 201, and the second capillary tube 113 exhausts the excess airflow of the vortex flow F. The second capillary tube 113 can be omitted.

[0056] [Third embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. The opening 111 of the vortex generator 100 is not limited to a cylindrical shape (diameter 5 mm, length 5 mm in the example shown in FIG. 1) as shown in the first and second embodiments. In other words, the shape of the opening 111 can be modified according to the composition and flow rate of the sample solution LQ (see FIG. 5) introduced into the ion source 2. For example, even if the opening 111 is cylindrical, the diameter can be changed. In the example shown in FIG. 10 and FIG. 11, the openings 111c, 111d have a truncated cone shape. Note that in FIG. 11 and FIG. 12, the same components as in FIG. 2 are denoted by the same reference numerals and description thereof will be omitted.

[0057] FIG. 11 is a top view of a vortex generating device 100c according to the third embodiment. The diameter of the opening 111c of the vortex generator 100c shown in Fig. 11 is configured to be larger on the side of the metal probe 201 than on the side of the first fine hole 301. In other words, the opening 11c is provided so that it is narrower on the side of the first fine hole 301 and wider on the side of the metal probe 201. The opening 111c shown in Fig. 11 can have a larger diameter on the side where the charged droplets Q (see Fig. 5) are introduced, making it easier to introduce the charged droplets Q (see Fig. 5) into the opening 111c.

[0058] FIG. 12 is a top view of a vortex generating device 100d according to the third embodiment. 12, the diameter of the opening 111d is smaller on the side of the metal probe 201 than on the side of the first fine hole 301. The opening 111d is wider on the side of the first fine hole 301 and narrower on the side of the metal probe 201. With this configuration, the centrifugal force caused by the vortex F on the side of the metal probe 201 of the opening 111d is stronger than in the vortex generator 100 shown in the first embodiment. As a result, the larger charged droplets Q are excluded by the centrifugal force, and only the smaller charged droplets Q can be introduced into the opening 111d.

[0059] In both the vortex flow generating device 100c shown in Fig. 11 and the vortex flow generating device 100d shown in Fig. 12, an airflow F1 is sent from a first capillary 112, as in the first embodiment. As a result, a vortex F is generated within an opening 111 of the vortex flow generating device 100. This makes it possible to increase the signal intensity detected by the mass spectrometer 1, as in the first embodiment.

[0060] [General mass spectrometer 1z] FIG. 13 is a diagram showing an example of a mass spectrometer 1z using a commonly used ion source 2. The mass spectrometer 1z has an ion source (electrospray ion source) 2, a pressure reduction section 4, and a vacuum section 5. A counter electrode 300 having a first pore 301 is provided between the ion source 2 and the pressure reduction section 4, and an electrode 400 having a second pore 401 is provided between the pressure reduction section 4 and the vacuum section 5. Furthermore, the vacuum section 5 is equipped with a mass analysis section 510 and an ion detector 520.

[0061] The ion source 2 is composed of a metal probe 201 and a high-voltage power supply 21. After a high voltage of several kV is applied between the metal probe 201 and the opposing electrode 300, a sample solution LQ is introduced into one end of the metal probe 201. Then, the sample solution LQ is sprayed from the nozzle of the metal probe 201 toward the opposing electrode 300. This spray contains a large number of charged droplets Q. If the particle size of the charged droplets Q is sufficiently small, they are dried (desolvated) while moving in the atmosphere, and ions N are extracted from the charged droplets Q into the gas phase. The ions N thus generated are introduced into the mass analysis section 510 arranged in the vacuum section 5 via the first fine hole 301, the pressure reduction section 4, and the second fine hole 401.

[0062] A voltage of several tens of volts (drift voltage) is applied between the first aperture 301 and the second aperture 401 to drift the ions N toward the second aperture 401. The pressure reduction section 4 and the vacuum section 5 are evacuated by vacuum pumps (not shown) having appropriate exhaust speeds. The mass analysis section 510 uses various techniques such as quadrupole type, ion trap type, and time-of-flight type. The mass analysis section 510 separates the ions N based on the difference in m / z and detects them with the ion detector 520. At this time, it is known that the performance of the mass spectrometer 1z is improved by causing a swirling vortex flow (vortex flow F) to flow from the first aperture 301 side toward the ion source 2 side. A member that generates the vortex flow F is installed in front of the first aperture 301, but is not shown in FIG. 13.

[0063] In the mass spectrometer 1z shown in FIG. 13, the structure of the component that generates the vortex F is complex, for example, a spiral groove is provided in the component placed in front of the first aperture 301 to generate the vortex F, which is a factor in increasing costs.

[0064] The vortex generators 100, 100a to 100d according to the first to third embodiments can generate a vortex F with a simple structure from the first aperture side toward the ion source 2 side. This makes it possible to provide a highly sensitive ion source 2 and mass spectrometer 1 at low cost.

[0065] The present invention is not limited to the above-described embodiment, and includes various modified examples. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0066] Furthermore, the size of the plate-like portion 110 may be any size and shape as long as the opening 111 can be provided therein. Furthermore, the circular cross-sectional shape of the opening 111 is preferably a perfect circle or an almost perfect circle, but may be any circle within a range that achieves the object and effect of the present invention. Furthermore, the cross section may be an ellipse, an oblong hole, or a polygon within a range that does not impair the object and effect of the present invention.

[0067] In addition, in each embodiment, the control lines and information lines are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. In reality, it can be considered that almost all components are connected to each other. [Explanation of symbols]

[0068] 1,1z mass spectrometer 2. Ion source (electrospray ion source) 100, 100a~100d Vortex generator 110 Plate-shaped part 111,111c,111d opening 112 First capillary tube (outlet) 112a Third capillary tube (outlet) 113 Second capillary (suction part) 121 Heater (heating part) 122 Insulation 131 Interposition section 141 Heater (heating part) 151 Central axis 201 Metal Probe 300 Counter electrode 301 First pore (pore) 400 electrodes 401 Second hole 510 Mass spectrometry department 520 Ion Detector 601~604 Power supply a1,a2,b1,b2 position A1 Solid Arrow A11~A13 White arrows F vortex F1, F1a~F1c Airflow LQ sample solution L11 Line L12 line L21 line N ions Q Charged droplets

Claims

1. A plate-like portion that is a plate-like member having an opening that is a through hole and a predetermined thickness; The opening has a circular cross section perpendicular to an axial direction of the opening, The opening has an outlet portion that outlets an airflow in a tangential direction of an outer shape of the opening and in an axial direction of the opening. Vortex generator.

2. The outlet portion is provided at a predetermined angle greater than 0° and less than 90° with respect to the central axis of the opening portion.

2. A vortex generator according to claim 1.

3. The predetermined angle is an angle through which the airflow can rotate at least once inside the opening.

3. A vortex generator according to claim 2.

4. A heating unit for heating the airflow is provided.

2. A vortex generator according to claim 1.

5. The heating portion is provided on the plate-shaped portion via an insulating portion.

5. A vortex generator according to claim 4.

6. A suction unit is provided to suck in the guided airflow.

2. A vortex generator according to claim 1.

7. The outlet portion is provided in plurality.

2. A vortex generator according to claim 1.

8. The plurality of lead-out portions include The air flows guided from each of the plurality of outlet parts are arranged to flow through the opening part while forming a spiral shape with respect to each other.

8. A vortex generator according to claim 7.

9. The plurality of lead-out portions include The airflow led out from a given outlet portion is biased by the airflow led out from another outlet portion.

8. A vortex generator according to claim 7.

10. an electrospray ion source having a metal probe into which a sample solution is introduced and which sprays the sample solution as charged droplets when a high voltage is applied; a pore for taking in ions generated from the charged droplets into a vacuum; A mass spectrometer having a mass analysis unit for performing mass analysis on the ions taken in through the aperture, and a vortex generator is provided between the metal probe and the aperture, The vortex generating device is A plate-like portion that is a plate-like member having an opening that is a through hole and a predetermined thickness; The opening has a circular cross section perpendicular to an axial direction of the opening, The opening has an outlet portion for guiding an airflow in a tangential direction of the outer shape of the opening and from the side of the fine hole toward the side of the metal probe. Mass spectrometer.

11. An intervening portion is provided to seal the space between the fine hole and the vortex generator.

11. The mass spectrometer of claim 10.

12. The plate-shaped portion is made of a conductive material, A voltage is applied to each of the metal probe, the plate-like portion of the vortex current generating device, and the electrode in which the fine hole is provided, The voltage is applied so that ions based on the charged droplets sprayed from the metal probe move toward the pore.

11. The mass spectrometer of claim 10.

13. the opening has a frusto-conical shape; The opening is provided so that the side of the opening facing the hole is narrower and the side of the opening facing the metal probe is wider.

11. The mass spectrometer of claim 10.

14. the opening has a frusto-conical shape; The opening is provided so that the side of the opening facing the hole is wider and the side of the opening facing the metal probe is narrower.

11. The mass spectrometer of claim 10.

Images