Ion source and analysis device using same

Abstract

Provided is a new ion source that produces microdroplets from a liquid sample continuously supplied from a liquid chromatograph or the like, electrically charges the microdroplets, executes a series of treatments for vaporizing a solvent at a low gas flow rate, and introduces ions of a solute component contained in the liquid sample into an analysis block. This ion source is for supplying, to an analysis block for analyzing a liquid sample containing a solute component, ions of the solute component, the ion source comprising: a droplet production unit that produces droplets of the liquid sample; a heated and pressure-adjusted gas supply block that heats a carrier gas that flows therein from the droplet production unit together with the droplets; and an electrically charging unit that electrically charges the solute component and ionizes the same. The heated and pressure-adjusted gas supply block includes: a sample transport tube path that is arranged between the analysis block and the droplet production unit; a heated and pressure-adjusted gas reservoir unit that is configured to be in contact with the sample transport tube path so that heat can be transferred therebetween; a gas-heating unit that heats a prescribed gas to a prescribed temperature; and a pressure-adjusting unit that maintains the pressure of the prescribed gas in a prescribed range. The droplets and the carrier gas are heated by the heated prescribed gas. The droplets and the carrier gas are supplied from the droplet production unit to the sample transport tube path. The heated prescribed gas is introduced from the heated and pressure-adjusted gas reservoir unit into the sample transport tube path.

Description

Ion source and analytical device using same

[0001] The present disclosure relates to an ion source and an analytical device using the same.

[0002] In devices for analyzing components in liquid samples containing various solute components, the liquid sample is atomized into fine droplets, and the solvent components are vaporized to remove the solute components of the sample, which are then atomized and introduced into the analytical section, etc. A typical example of a device that uses this method of analysis is a liquid chromatograph mass spectrometer.

[0003] In a liquid chromatograph mass spectrometer, a liquid sample containing various components separated by a liquid chromatograph is converted into minute droplets, which are then charged and heated and vaporized in an ion source to generate ions of the solute components.The ionized solute components are then introduced into a mass spectrometer, where they are separated by their mass-to-charge ratio and the components are identified.

[0004] Methods used in ion sources include electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI).

[0005] Gas spraying is commonly used to turn liquid samples into microdroplets in liquid chromatograph mass spectrometers, etc. Here, gas spraying refers to a method in which a high-speed gas jet is applied to the liquid, breaking it into microdroplets and spraying them.

[0006] In an ion source, a liquid sample must be converted into very small droplets with a diameter of about several micrometers, so a gas spray using an ultra-high-speed gas flow with a jet velocity of several hundred meters per second is used.

[0007] Additionally, development is underway on a device that uses an ultrasonic vibrator to generate the microdroplets to be introduced into the ion source.

[0008] The following is a conventional technique for applying an atomizing device using an ultrasonic vibrator to an ion source.

[0009] Patent Document 1 discloses a configuration in which an eluent for liquid chromatography is sprayed onto the surface of an ultrasonic vibrator using a high-pressure gas nebulizer, and an extremely fine mist is created by the action of the ultrasonic vibrator, and the solvent is removed from the mist, and the desolvated sample is introduced to a subsequent atmospheric pressure ion source and subjected to mass spectrometry.

[0010] Patent Document 2 discloses an ion generating device in a mass spectrometry system, which uses an ultrasonic vibrator to atomize a liquid containing a sample having an ionic group and a protic polar solvent, and heats the liquid to remove the protic polar solvent.

[0011] JP 11-051902 A JP 2015-031650 A

[0012] In a liquid chromatograph mass spectrometer, multiple types of liquid samples to be analyzed are continuously supplied from a liquid chromatograph through capillaries with diameters of several hundred micrometers or less. The amount of each liquid sample supplied is extremely small, at several hundred microliters or less. The droplet generator used in the mass spectrometer is required to continuously convert these liquid samples into microdroplets without mixing, impart an electric charge to the generated microdroplets, remove the solvent by heating, generate ions of the solute components, and continuously supply them to the analytical section.

[0013] The droplets formed by the ultra-high-speed gas flow of the gas spray used in the ion source are sprayed at an ultra-high speed, which requires a large amount of energy for processes such as charging and thermal vaporization, and the time required for these processes is short. Therefore, there is also the issue of stabilizing these processes.

[0014] Furthermore, because the liquid sample breaks down into tiny droplets in the high-speed, large-volume gas flow, only a small portion of the sample droplets can be introduced into the mass spectrometer, with the majority of the sample being discharged unused.

[0015] The devices described in Patent Documents 1 and 2 do not provide a solution to the problem of loss of the generated mist of microdroplets in the path that sends the microdroplets to the analysis device.

[0016] The object of the present disclosure is to provide a new ion source that generates microdroplets from a liquid sample continuously supplied from a liquid chromatograph or the like, imparts an electric charge to the microdroplets, and vaporizes the solvent, all of which are performed with a low gas flow rate, thereby introducing ions of solute components contained in the liquid sample into an analysis block.

[0017] The ion source disclosed herein supplies ions of solute components to an analysis block that analyzes a liquid sample containing solute components, and includes a droplet generation unit that generates droplets of the liquid sample, a heated and pressure-regulated gas supply block that heats the carrier gas that flows in from the droplet generation unit along with the droplets, and a charge imparting unit that imparts an electric charge to the solute components to ionize them.The heated and pressure-regulated gas supply block includes a sample transport pipeline arranged between the analysis block and the droplet generation unit, a heated and pressure-regulated gas retention unit that is in heat-transferable contact with the sample transport pipeline, a gas heating unit that heats a specified gas to a specified temperature, and a pressure adjustment unit that maintains the pressure of the specified gas within a specified range.The droplets and carrier gas are heated by the heated specified gas, and the sample transport pipeline is configured so that the droplets and carrier gas are supplied from the droplet generation unit and the heated specified gas is introduced from the heated and pressure-regulated gas retention unit.

[0018] According to the present disclosure, a new ion source can be provided that generates microdroplets from a liquid sample continuously supplied from a liquid chromatograph or the like, imparts an electric charge to the microdroplets, and vaporizes the solvent, all of which are performed with a low gas flow rate, thereby introducing ions of solute components contained in the liquid sample into an analysis block.

[0019] 1 is a cross-sectional view of a main part of an analytical device according to an embodiment. FIG. 2 is a front view of the liquid flow path plate 2 of FIG. 1. FIG. 2A is a cross-sectional view showing the liquid flow path plate 2 of FIG. 2A installed in an ion source. FIG. 2B is a partially enlarged view showing the micropore forming section 2d of FIG. 2A. FIG. 3A is a longitudinal cross-sectional view of the part shown in FIG. 3A. FIG. 3B is a cross-sectional view of the heated and pressure-adjusted gas supply block 11 of FIG. 1. FIG. 3C is a cross-sectional view of the charge imparting block 21 of FIG. 1. FIG. 3D is a partial cross-sectional view of the charge imparting block 21 as viewed from the analysis block 25 side of FIG. 1. FIG. 3E is a cross-sectional view of another charge imparting section in an embodiment. FIG. 6A is a cross-sectional view of the sample transport tube 13 as viewed from the heated and pressure-adjusted gas supply block 11 side.

[0020] The present disclosure relates to an ion source for ionizing components contained in a liquid sample to be analyzed by an analytical device such as a liquid chromatograph mass spectrometer and introducing the ionized components into an analysis block, and to an analytical device equipped with such an ion source.

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0022] FIG. 1 is a cross-sectional view of a main part of an analytical device according to an embodiment of the present invention.

[0023] The analytical device shown in this figure has a liquid sample atomization block 1 (droplet generation unit), a heated and pressure-regulated gas supply block 11, a charge imparting block 21, and an analysis block 25. These are connected in series. Of these, the liquid sample atomization block 1, the heated and pressure-regulated gas supply block 11, and the charge imparting block 21 constitute an ion source. The ion source is connected to the analysis block 25 via a connection block 22 having a capillary tube connection 23. The interior of the analysis block 25 is maintained in a nearly vacuum state (reduced pressure state).

[0024] The liquid sample atomization block 1 includes a thin liquid flow path plate 2 and an ultrasonic vibration imparting unit 3. The holder 9 is composed of a liquid sample supply side member 9a and a connecting member 9b, and the holder 10 is composed of a holder main portion 10a and a flange-shaped member 10b. The holder main portion 10a is approximately cylindrical. The liquid flow path plate 2 is sandwiched between the liquid sample supply side member 9a and the connecting member 9b. The ultrasonic vibration imparting unit 3 is a bolt-tightened Langevin transducer (BLT) composed of a tip vibrating portion 3a, a piezoelectric element portion 3b, and a screw housing 3c (piezoelectric element fixing body). The ultrasonic vibration imparting unit 3 and a rectifying plate 4 are inserted and fixed inside the holder main portion 10a. The holder main portion 10a is inserted into a through-hole in the liquid sample supply side member 9a.

[0025] The ultrasonic vibration imparting unit 3 is arranged so as to be in contact with the liquid flow path plate 2, and is configured so that the tip vibrating portion 3a of the ultrasonic vibration imparting unit 3 is in close contact with the liquid flow path plate 2 by pressing the flange-shaped member 10b attached to the main part 10a of the holder with a spring 7 (pressing member).

[0026] The liquid sample supply side member 9a is connected to a supply pipe 5 and a discharge pipe 8. A sample liquid 26a continuously supplied from the supply pipe 5 is supplied to the liquid flow path plate 2 and atomized. The remaining liquid that is not atomized is discharged from the discharge pipe 8 as a remaining sample liquid 26c.

[0027] A carrier gas supply pipe 6 is connected to the flange-shaped member 10b, and a carrier gas 27a is supplied into the holder main part 10a. The carrier gas 27a has a substantially uniform flow velocity distribution due to the flow straightening plate 4, passes around the ultrasonic vibration imparting unit 3, and is supplied to the heating and pressure regulating gas supply block 11 together with the liquid droplets generated on the liquid flow path plate 2. The carrier gas 27a passes through the side of the ultrasonic vibration imparting unit 3, which also serves to cool the ultrasonic vibration imparting unit 3.

[0028] The heated and pressure-adjusted gas supply block 11 includes an outer tube 12a, an inner tube 12b, a sample transport tube 13 (sample transport conduit), a heat insulating member 14, a mesh plate 15, an air heater 16 (gas heating section), and a pressure adjusting means 17 (pressure adjusting section). The outer tube 12a and the inner tube 12b constitute the heated and pressure-adjusted gas supply section main body 12 and have a double-tube structure. The annular section formed by the outer tube 12a and the inner tube 12b is an outer shell chamber 18 (heated and pressure-adjusted gas retention section).

[0029] A heat insulating member 14 is sandwiched between the outer tube 12a and the sample transport tube 13. The heat insulating member 14 does not easily transmit heat, so it prevents the liquid sample atomization block 1 from being heated by the heat of the high-temperature heated and pressure-adjusted gas supply block 11. In addition, the heat insulating member 14 has electrical insulation properties, so it also has the function of blocking current from the charge imparting block 21.

[0030] The microdroplets 26b flow together with the carrier gas 27b in the sample transport tube 13. The microdroplets 26b and the carrier gas 27b are supplied into the inner tube 12b.

[0031] The air heater 16 heats a predetermined flow rate of gas to a predetermined temperature and supplies it as heated gas 27c to the outer chamber 18. In this embodiment, nitrogen gas is used as the gas supplied to the outer chamber 18. In this case, in addition to nitrogen, inert gases such as argon and helium are desirable as the gas to be used.

[0032] The pressure in the outer shell chamber 18 is adjusted by the pressure adjusting means 17, and when the pressure exceeds a predetermined value, an exhaust gas flow 27g is generated.

[0033] The heated gas 27c passes through the outer shell chamber 18 and the mesh plate 15, forming a swirling airflow 27d, which is supplied into the inner tube 12b and merges with the solute particles 26d. The solute particles 26d are formed by heating the microdroplets 26b and evaporating the solvent. The solute particles 26d are supplied to the charge imparting block 21 together with the carrier gas 27e.

[0034] A discharge wire 20 stretched by a spring 19 is installed on the charge imparting block 21. Solute particles 26d supplied together with a carrier gas 27e are ionized by a discharge generated by a high voltage applied to the discharge wire 20.

[0035] The analysis block 25 includes an analysis unit (not shown) built into the housing 24. A connection block 22 having a capillary tube connection part 23 is sandwiched between the charge imparting block 21 and the housing 24. The ionized solute particles 26d pass through the capillary tube connection part 23 together with the carrier gas 27e and are supplied into the housing 24.

[0036] The internal area including the heated and pressure-adjusted gas supply block 11 from the liquid flow path plate 2 to the connection block 22 is made airtight, including the support part for the discharge wire 20 and the power supply terminal, to prevent the carrier gas flow from leaking from the central pipeline.

[0037] The solute particles 26d sent to the analysis block 25 are subjected to an analysis process of the components in the analysis block 25 as ionized solute components 27f.

[0038] FIG. 2A is a front view showing the liquid flow path plate 2 of FIG.

[0039] The liquid flow path plate 2 has a liquid flow path 2g therein. A supply port 2f and a discharge port 2h for a liquid sample are provided at the ends of the liquid flow path 2g. A micropore forming section 2d having a plurality of micropores is provided in the center of the liquid flow path 2g. Four carrier gas through holes 2e are provided around the micropore forming section 2d.

[0040] 2B is a cross-sectional view showing the liquid flow path plate 2 of FIG. 2A installed in an ion source. Note that the liquid flow path plate 2 is a very thin plate compared to the dimensions of the other components, so in FIG. 2B, it is shown enlarged in the thickness direction.

[0041] The liquid flow path plate 2 has a structure in which three thin plates 2a, 2b, and 2c are stacked and joined together. A supply port 2f and a discharge port 2h for the sample liquid 26a are formed in the thin plate 2c on the side where the sample liquid 26a is supplied. The supply port 2f and the discharge port 2h are both through-holes. A long, thin hole is formed in the central thin plate 2b. This hole forms the liquid flow path 2g when the three thin plates 2a, 2b, and 2c are stacked together. A micropore forming section 2d in which multiple micropores (through-holes) are formed is provided in the center of the thin plate 2a. This micropore connects the liquid flow path 2g to the outer surface of the thin plate 2a.

[0042] In this example, the three thin plates 2a, 2b, and 2c are made of stainless steel and have a thickness of 50 μm. These three thin plates 2a, 2b, and 2c are stacked and diffusion bonded together to form a 150 μm-thick liquid flow path plate 2. Because diffusion bonding is a bonding method that does not require adhesives, it is also possible to flow liquid samples containing solvents through the liquid flow path plate 2.

[0043] The liquid flow path plate 2 is sandwiched between a liquid sample supply side member 9a and a connecting member 9b. The liquid sample supply side member 9a and the connecting member 9b each have a recess in their center so as not to come into direct contact with the center of the liquid flow path plate 2. In other words, the liquid sample supply side member 9a and the connecting member 9b hold the peripheral edge of the liquid flow path plate 2 and support the liquid flow path plate 2.

[0044] The tip vibrating portion 3a of the ultrasonic vibration imparting unit 3 is pressed against the center of the liquid flow path plate 2 (thin plate 2c).

[0045] The liquid sample supply side member 9a has a through-hole for supplying the sample liquid 26a and a through-hole for discharging the remaining sample liquid 26c. The through-hole for supplying the sample liquid 26a is connected to the supply port 2f of the thin plate 2c. The through-hole for discharging the remaining sample liquid 26c is connected to the discharge port 2h of the thin plate 2c. The sample liquid 26a passes through the supply port 2f and is sent to the liquid flow path 2g in the liquid flow path plate 2. Then, due to ultrasonic vibrations in the thickness direction of the liquid flow path plate 2 applied from the tip vibration portion 3a of the ultrasonic vibration imparting unit 3, a portion of the sample liquid 26a is released from the micropores of the micropore forming portion 2d provided midway along the liquid flow path 2g, forming microdroplets 26b. The microdroplets 26b are then sent to the left in the figure together with the carrier gas 27b that has passed through the carrier gas through-hole 2e of the liquid flow path plate 2. The carrier gas 27b flows so as to surround the flow of the microdroplets 26b. In other words, the microdroplets 26b flow through the center of the flow channel, and the carrier gas 27b flows through the outer periphery of the flow channel.

[0046] The remainder of the sample liquid 26a passes through the outlet 2h and is discharged as a remaining sample liquid 26c.

[0047] By adopting such a structure, even when the type of sample liquid 26a being continuously supplied is changed, the sample liquid 26a flowing through the liquid flow path 2g does not mix, and continuous micro-dropletization is achieved in accordance with the change in the type of sample liquid 26a.

[0048] The minute droplets 26b flow while being surrounded by the carrier gas 27b, and are therefore stably transported toward the heating and pressure adjusting gas supply block 11 as shown in FIG.

[0049] FIG. 3A is a partially enlarged view showing the micropore forming portion 2d of FIG. 2A.

[0050] 3A, the numerous micropores formed in the micropore forming portion 2d are shown as dots, and the liquid flow path 2g inside the liquid flow path plate 2 and the tip vibrating portion 3a in contact with the back surface of the liquid flow path plate 2 are shown by dotted lines.

[0051] FIG. 3B is a longitudinal cross-sectional view of the portion shown in FIG. 3A.

[0052] 3B shows a stacked configuration of three thin plates 2a, 2b, and 2c, a tip vibration part 3a in contact with thin plate 2c, and a large number of micropores in a micropore forming part 2d formed in thin plate 2a. In other words, the tip vibration part 3a of the ultrasonic vibration imparting unit 3 is in contact with the surface of the liquid flow path plate 2 opposite to the surface on which the micropore forming part 2d is provided.

[0053] The diameter of the microdroplets 26b shown in Figure 2B is affected by the ultrasonic vibration frequency and the diameter of the micropores. In this example, to form microdroplets 26b of about a few micrometers, the ultrasonic vibration frequency was set to about 150 kHz and the diameter of the narrowest part of the micropore was set to 4 μm. As a result, droplets with diameters of 4 to 6 μm were formed. Almost no droplets with diameters of 10 μm or more were observed, and no droplets with diameters of 20 μm or more were observed.

[0054] From the results of this experiment, it was found that in order to form minute droplets of about several micrometers, it is necessary to apply vibration at a frequency of about several hundred kHz and to form minute holes with a narrowest diameter of several micrometers or less.

[0055] In addition, methods such as laser processing and electroforming can be used to form such micropores, but in this example, YAG laser processing was used because of the large number of micropores, the fact that stainless steel was selected as the material, and also because of cost considerations.

[0056] In many processing methods, this type of micromachining results in differences in hole diameter in the thickness direction. In the processing of microholes using a YAG laser in this example, the hole diameter on the irradiated side when microholes with a diameter of 4 μm were formed was approximately several tens of μm. In the thin plate 2a of this example, the diameter of the microholes on the surface side was set to approximately 4 μm. This was because, as a result of investigation, it was found that a larger diameter on the flow path side and a smaller diameter on the surface side made it easier for the liquid to be released in a mist form and made it more difficult for liquid droplets to form on the surface of the flow path plate. If liquid droplets were to form on the surface side of the flow path plate, the release of the liquid would become unstable.

[0057] Furthermore, the microdroplets 26b shown in FIG. 2B have a slow initial velocity and a small droplet diameter, so that the microdroplets 26b can be transported stably even when the flow rate of the carrier gas 27b is low.

[0058] In this embodiment, nitrogen gas of 1 L / min is used as the carrier gas 27b, and stable transportation of the microdroplets 26b is achieved at a transport speed of about 1 m / s within the sample transport tube 13 shown in FIG.

[0059] In this embodiment, the droplet generating unit is configured to have a liquid flow path plate 2, which is a plate-shaped member, but the droplet generating unit according to the present disclosure is not limited to this and may also be configured to have a liquid flow path formed inside a pipe.

[0060] Furthermore, in this embodiment, the droplet generating unit is configured to generate droplets using the ultrasonic vibration imparting unit 3, but the droplet generating unit according to the present disclosure is not limited to this and may be configured to generate droplets using a gas spray method or the like.

[0061] FIG. 4 is a cross-sectional view showing the heated and pressure-adjusting gas supply block 11 of FIG.

[0062] 4 shows a cross section passing through the central axes of the air heater 16 and the pressure adjusting means 17, and the direction in which the minute droplets 26b shown in FIG. 1 are transported is perpendicular to the drawing.

[0063] As shown in FIG. 4, heated gas 27c supplied from the air heater 16 flows through the outer shell chamber 18 inside the outer pipe 12a, and becomes an air flow 27h that swirls around the inner pipe 12b.

[0064] The volume of gas changes significantly when heated. When the volume of the heated gas 27c supplied from the air heater 16 changes, the pressure inside the outer shell chamber 18 changes. In this embodiment, a pressure regulating means 17 is provided in the outer shell chamber 18, so that the pressure inside the outer shell chamber 18 does not change even when the volume of the heated gas supplied from the air heater 16 changes. The pressure regulating means 17 in this embodiment utilizes a valve that opens when the internal pressure reaches a predetermined pressure. By providing the pressure regulating means 17, when the pressure of the air flow 27h supplied from the air heater 16 into the outer tube 12a rises to a predetermined value, a portion of the gas inside the outer shell chamber 18 is discharged from the pressure regulating means 17. This makes it possible to maintain a constant pressure of the heated gas inside the outer shell chamber 18.

[0065] The heated and pressure-regulated airflow 27h in the outer shell chamber 18 passes through the mesh plate 15 and is supplied to the inner tube 12b. The swirling airflow 27d is introduced from the outer periphery of the interior of the inner tube 12b and flows into the inner tube 12b, swirling and enveloping the microdroplets 26b and carrier gas 27b transported from the sample transport tube 13 shown in FIG.

[0066] In this embodiment, the inner diameter of the inner tube 12 b is larger than the inner diameter of the sample transport tube 13 .

[0067] This is for the following reasons.

[0068] This is to prevent the gas flow rate inside the inner tube 12b from increasing due to the merging of the swirling airflow 27d and the carrier gas 27b containing the microdroplets 26b. If the gas flow rate increases, it is necessary to increase the length of the flow path in consideration of the distance required for the swirling airflow 27d and the carrier gas 27b containing the microdroplets 26b to mix and the time required for the solvent in the microdroplets 26b to evaporate.

[0069] Increasing the length of the flow path not only increases the size of the device, but also increases the possibility that the microdroplets 26b and their solute components contained in the carrier gas 27b will come into contact with the inner wall surface of the inner tube 12b. If the solute components contained in the microdroplets 26b to be analyzed come into contact with the inner wall surface of the inner tube 12b, which is at a high temperature, they will be burned away.

[0070] Burning off solute components is effective in preventing contamination with components contained in other liquid samples sent later, but it also reduces the amount of solute components that can be introduced into the analysis block.

[0071] Therefore, the inner diameter of the inner tube 12 b is made larger than the inner diameter of the sample transport tube 13 .

[0072] In this embodiment, the inner diameter of the inner tube 12b is made larger than the inner diameter of the sample transport tube 13, and the pressure of the heated gas is maintained within a predetermined range by the pressure adjustment means 17, thereby suppressing changes in the air flow caused by the confluence of the swirling air flow 27d and the transport gas 27b.

[0073] Furthermore, the swirling airflow 27d supplied to the inner tube 12b is made a gentle flow, and by swirling and enveloping the carrier gas 27b from around it, more solute components can be introduced into the analysis block.

[0074] In this way, by adjusting the pressure of the heated gas before supplying it to the inner tube 12b, the pressure in the inner tube 12b is also maintained within a predetermined range, and in this state the solvent contained in the microdroplets 26b can be heated and vaporized.

[0075] Next, the charge applying section of this embodiment will be described.

[0076] FIG. 5A is a cross-sectional view showing the charge-imparting block 21 of FIG.

[0077] The configuration shown in FIG. 5A is shown in FIG. 1, and therefore a description thereof will be omitted here.

[0078] FIG. 5B is a partial cross-sectional view of the charge-imparting block 21 as viewed from the analysis block 25 side of FIG.

[0079] 5A and 5B each show a cross section including the position where the discharge wire 20 is stretched.

[0080] 5B shows the connection block 22 as seen from the front. The capillary tube connection 23 (micropore) connecting to the analysis block is provided in the center of the connection block 22. The inner diameter of the capillary tube connection 23 is preferably one-fifth or less, and more preferably one-tenth or less, of the inner diameter of the downstream end of the sample transport pipeline. In terms of actual dimensions, the inner diameter of the capillary tube connection 23 is preferably 1 mm or less, and more preferably 100 μm or less.

[0081] A discharge wire 20 is stretched across a conduit hole provided in the center of the charge imparting block 21. The charge imparting block 21 is made of an insulating material. A spring 19 and a power supply terminal are provided to stretch the discharge wire 20.

[0082] A high-voltage power supply 28 is connected to the discharge wire 20. By applying a high voltage to the discharge wire 20 from the high-voltage power supply 28, a potential difference is created between the discharge wire 20 and the connection block 22, generating a corona discharge. The positive ions and electrons generated by the corona discharge can impart an electric charge to the solute components in the carrier gas. The current and polarity of the high-voltage power supply 28 are controlled according to the solute components.

[0083] Carrier gas 27e containing the charged solute component passes through a capillary tube connector 23 provided in the connection block 22 and is supplied as a solute component 27f into the interior of the housing 24. The interior of the housing 24 is maintained in a substantially vacuum state, and the amount of carrier gas 27e passing through the capillary tube connector 23 is affected by the pressure of the carrier gas 27e in the transport pipeline.

[0084] In this embodiment, by adopting a structure in which the pressure and flow rate of the carrier gas 27e in the carrier pipeline are stably maintained at predetermined conditions, it is possible to supply almost all of the carrier gas 27e containing solute components (ions) in the carrier pipeline to the inside of the housing 24. To achieve this, a pressure adjustment means 17 is provided in the heated pressure adjustment gas supply block 11.

[0085] Next, an example of the setting conditions in this embodiment will be described.

[0086] Under conditions where the external pressure is approximately atmospheric pressure, the amount of carrier gas 27e passing through the capillary connection part 23 of the connection block 22 is approximately 7 L / min. Therefore, the flow rate of the carrier gas supplied from the liquid sample atomization block 1 is set to approximately 1 L / min, and the flow rate of the swirling airflow 27d supplied from the heated pressure adjustment gas supply block 11 is set to approximately 6 L / min. As an example of actual settings, heated gas is supplied from the air heater 16 to the outer chamber 18 of the heated pressure adjustment gas supply block 11 at a rate slightly greater than approximately 6 L / min, and the leak pressure of the pressure adjustment means 17 is set to 1 atmosphere (atmospheric pressure).

[0087] By setting it in this manner, the pressure of the carrier gas 27e flowing through the pipeline becomes approximately atmospheric pressure, and only an amount that is balanced with the amount of carrier gas 27e passing through the capillary connection portion 23 of the connection block 22 is supplied as a swirling airflow 27d from the outer shell chamber 18 of the heated pressure-regulating gas supply block 11 to the inner pipeline.

[0088] As described above, the structure of this embodiment makes it possible to stably introduce into the analysis block both the gas stream containing the sample liquid atomized by the liquid sample atomization block 1 and the gas stream that heats and vaporizes it. This allows solute components contained in many liquid samples to be introduced into the analysis block, greatly improving the sensitivity of the analysis device.

[0089] Next, another charge applying section in this embodiment will be described.

[0090] As described above, the charge imparting unit shown in Figures 5A and 5B evaporates the solvent components of the droplet sample in the heated and pressure-adjusted gas supply block 11, and then ionizes the solute components by irradiating them with corona ions in the charge imparting block 21.

[0091] In the ion sources of current mass spectrometers, in addition to methods for imparting a charge to solute components after completely vaporizing the solvent components, such as the charge imparting block 21 shown in Figures 5A and 5B, methods for imparting a charge to droplets immediately after their formation are also used. These methods are called atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI), respectively. These two methods differ in analytical sensitivity depending on the molecular weight and other characteristics of the solute components being analyzed, and therefore are used differently depending on the type of solute component, etc.

[0092] In this embodiment as well, it is desirable to provide a charge imparting section that imparts a charge to the droplets immediately after the formation of the microdroplets, in addition to the charge imparting section shown in FIGS. 5A and 5B that imparts a charge to the solute component after the solvent has evaporated.

[0093] FIG. 6A is a cross-sectional view showing another charge applying portion in this embodiment.

[0094] In this figure, a charge imparting unit is placed in the sample transport tube 13, which is the inlet of the heated and pressure-adjusted gas supply block 11 shown in Figure 1. The liquid sample supply side member 9a, which is the holder 9 of the liquid flow path plate 2 of the liquid sample atomization block 1, is made of a conductive material, and the connecting member 9b is made of an insulating material. The sample transport tube 13 is also made of a conductive material, and is connected to the heated and pressure-adjusted gas supply block 11 side via a heat-insulating and insulating member 14.

[0095] A variable power supply 29 capable of applying both positive and negative voltages is disposed between the sample transport tube 13 and the liquid sample supply member 9a. The liquid sample supply member 9a is in electrical contact with the liquid flow path plate 2. This allows an electric field to be generated between the sample transport tube 13 and the surface of the liquid flow path plate 2 that releases sample droplets.

[0096] Since an electric field is also generated in the sample droplets ejected from the liquid flow path plate 2 in which an electric field is generated, an electric charge is imparted to the formed droplets. This effect of imparting a charge to the droplets is the same as in the current electrospray method. In other words, even in the droplet atomization configuration of the present disclosure in which the thin liquid flow path plate 2 is ultrasonically vibrated, it is possible to impart a charge to the droplets in a manner equivalent to that of the electrospray method.

[0097] FIG. 6B is a cross-sectional view of the sample transport tube 13 in FIG. 6A as viewed from the heating and pressure adjustment gas supply block 11 side.

[0098] 6B, electric wires 61 are arranged inside the flow path of the sample transport tube 13, rather than on the wall surface of the sample transport tube 13, as electrodes for generating an electric field on the surface of the liquid flow path plate 2. Three electric wires 61 are arranged in a Y-shape (radially) at 120-degree intervals.

[0099] This causes the direction of the electric field generated on the surface of the liquid flow path plate 2 to more closely match the direction of the carrier gas 27b flowing inside the sample transport tube 13. This stabilizes the direction of travel of the charged microdroplets 26b, prevents the microdroplets 26b from colliding with the wall surface of the sample transport tube 13, and reduces the amount of microdroplets 26b lost. As a result, more microdroplets 26b are supplied to the heated and pressure-adjusted gas supply block 11.

[0100] When the microdroplets 26b ejected from the liquid flow path plate 2 are charged while containing a solvent using the configuration shown in FIGS. 6A and 6B, charging by corona ions as shown in FIGS. 5A and 5B is not necessary.

[0101] By controlling the switching between charging by corona ions as shown in FIGS. 5A and 5B and charging during droplet formation as shown in FIGS. 6A and 6B, two types of charging means can be selected and appropriately implemented in one ion source.

[0102] As described above, the ion source of the present disclosure can minimize and appropriately control the amounts of the gas flow that transports the microdroplets and the heated gas flow that vaporizes the solvent. Therefore, an analytical device equipped with the ion source of the present disclosure can introduce many of the solute components contained in the sample liquid into the analysis block, significantly improving the sensitivity of the analytical device.

[0103] The present disclosure provides a new ion source that can introduce many of the generated solute component ions into a mass spectrometer, and also provides a mass spectrometer that uses the ion source and has high analytical sensitivity.

[0104] Preferred embodiments of the present disclosure will be summarized below.

[0105] In the ion source, the droplet generating section has an ultrasonic vibration imparting unit, and droplets are generated by the ultrasonic vibration imparting unit.

[0106] The droplet generating section has a liquid flow path formed inside a pipe or a plate-like member, the pipe or plate-like member has micropores connecting its outside with the liquid flow path, the ultrasonic vibration imparting unit is configured to impart ultrasonic vibrations to the liquid sample flowing in the liquid flow path, and the droplets are released from the micropores.

[0107] The droplet generating section has a configuration in which droplets flow into the center of the sample transport pipeline, and a carrier gas flows into the sample transport pipeline so as to surround the flow of droplets.

[0108] The predetermined gas introduced from the heated and pressure-adjusted gas reservoir into the sample transport pipeline is configured to flow in so as to surround the droplets and the flow of the transport gas.

[0109] The sample transport conduit has a larger cross-sectional area downstream of the position where the predetermined gas flows in than upstream of the position. If the sample transport conduit has a circular cross section, the inner diameter of the cross section of the conduit downstream of the position where the predetermined gas flows in is larger downstream than upstream.

[0110] The charge applying unit is configured to be disposed between the analysis block and the heated and pressure-regulating gas supply block.

[0111] The charge applying unit is disposed between the heating and pressure adjusting gas supply block and the droplet generating unit.

[0112] The analyzer includes an ion source and an analysis block.

[0113] The ion source and the analysis block are connected by a capillary connection, and the ionized solute components are supplied to the analysis block through the capillary connection.

[0114] 1: liquid sample atomization block, 2: liquid flow path plate, 2a, 2b, 2c: thin plate, 2d: micropore formation section, 2e: carrier gas through hole, 2f: supply port, 2g: liquid flow path, 2h: outlet port, 3: ultrasonic vibration imparting unit, 3a: tip vibration section, 3b: piezoelectric element section, 3c: screw housing, 4: rectifying plate, 5: supply pipe, 6: carrier gas supply pipe, 7: spring, 8: outlet pipe, 9: holder, 9a: liquid sample supply side member, 9b: connecting member, 10: holder, 10a: holder main section, 10b: flange-shaped member, 11: heated and pressure-regulated gas supply block, 12: heated and pressure-regulated gas supply section main body, 12a: outer tube, 12 b: inner tube, 13: sample transport tube, 14: heat insulation / insulation member, 15: mesh plate, 16: air heater, 17: pressure adjustment means, 18: outer shell chamber, 19: spring, 20: discharge wire, 21: charge application block, 22: connection block, 23: capillary connection part, 24: housing, 25: analysis block, 26a: sample liquid, 26b: microdroplets, 26c: remaining sample liquid, 26d: solute particles, 27a, 27b: carrier gas, 27c: heated gas, 27d: swirling air flow, 27e: carrier gas, 27f: solute component, 27g: exhaust gas flow, 27h: air flow, 28: high-voltage power supply, 29: variable power supply, 61: electric wire.

Claims

1. An ion source for supplying ions of a solute component to an analysis block for analyzing a liquid sample containing the solute component, A droplet generating unit for generating droplets of the liquid sample; a heating and pressure adjusting gas supply block for heating the carrier gas flowing in from the droplet generating unit together with the droplets; a charge imparting unit that imparts a charge to the solute component to ionize the solute component, The heating and pressure adjusting gas supply block includes: a sample transport pipeline disposed between the analysis block and the droplet generating unit; a heating and pressure adjusting gas retention section configured to be in heat transferable contact with the sample transport pipe; a gas heating unit that heats a predetermined gas to a predetermined temperature; A pressure adjusting unit that maintains the pressure of the predetermined gas within a predetermined range, the droplets and the carrier gas are heated by the heated predetermined gas, the droplets and the carrier gas are supplied to the sample transport pipeline from the droplet generating unit, and the predetermined gas heated from the heating and pressure adjusting gas retention unit is introduced from an upstream portion of the sample transport pipeline so as to swirl and envelop the droplets and the carrier gas; an inner diameter of a flow path for the droplet, the carrier gas, and the predetermined gas from the upstream portion of the sample transport pipeline to the upstream portion of the capillary tube connection portion of the analysis block is substantially constant; an inner diameter of the upstream portion of the sample transport pipeline is larger than an inner diameter of a portion of the droplet generating portion where the droplets and the transport gas are introduced;

2. The droplet generating unit has an ultrasonic vibration imparting unit, The ion source according to claim 1 , wherein the droplets are generated by the ultrasonic vibration imparting unit.

3. the droplet generating unit has a liquid flow path formed inside a pipe or a plate-like member, the pipe or the plate-like member has micropores that communicate between an outside of the pipe or the plate-like member and the liquid flow path, the ultrasonic vibration imparting unit is configured to impart ultrasonic vibration to the liquid sample flowing in the liquid flow channel; The ion source of claim 2 , wherein the droplets are expelled from the micropore.

4. 2. The ion source according to claim 1, wherein the droplet generating section has a configuration in which the droplets flow into a center portion of the sample transport pipe, and the carrier gas flows into the sample transport pipe so as to surround the flow of the droplets.

5. 2. The ion source according to claim 1, wherein the predetermined gas introduced from the heating and pressure adjusting gas retention section into the sample transport pipeline flows in such a way as to surround the droplets and the transport gas flow.

6. 6. The ion source according to claim 5, wherein the sample transport pipe has a flow passage cross-sectional area wider downstream of the position where the predetermined gas flows in than upstream of the position.

7. The ion source according to claim 1 , wherein the charge applying unit is configured to be disposed between the analysis block and the heated and pressure regulating gas supply block.

8. The ion source according to claim 1 , wherein the charge imparting section is disposed between the heating and pressure adjusting gas supply block and the droplet generating section.

9. An ion source according to any one of claims 1 to 8; An analysis device comprising the analysis block.

10. the ion source and the analysis block are connected by the capillary connection; 10. The analysis device according to claim 9, wherein the ionized solute components are supplied to the analysis block through the capillary connection.