WO2024047723A1

WO2024047723A1 - Ion source and analysis device using same

Info

Publication number: WO2024047723A1
Application number: PCT/JP2022/032487
Authority: WO
Inventors: 徹宮坂; 康照井
Original assignee: 株式会社日立ハイテク
Priority date: 2022-08-30
Filing date: 2022-08-30
Publication date: 2024-03-07

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 analyzer using it

The present disclosure relates to an ion source and an analysis device using the same.

In devices that analyze components in liquid samples containing various solute components, a method is used in which the liquid sample is atomized into minute droplets, the solvent components are vaporized and the solute components of the sample are atomized, and the solute components of the sample are introduced into the analysis section. is used. A typical example of a device that performs analysis using this method is a liquid chromatograph mass spectrometer.

In a liquid chromatograph mass spectrometer, a liquid sample containing various components separated by a liquid chromatograph is made into minute droplets, and the droplets are charged and heated in an ion source to generate ions of solute components. The ionized solute components are then introduced into a mass spectrometer and separated by mass-to-charge ratio to identify the components.

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

A gas spray method is usually used to turn a liquid sample into minute droplets in a liquid chromatograph mass spectrometer or the like. Here, the gas spray method refers to a method in which a high-speed gas jet is applied to a liquid to tear the liquid, turn it into minute droplets, and spray the liquid.

In the ion source, it is necessary to turn the liquid sample into very small droplets with a diameter of several μm, so a gas spray using an ultrahigh-speed gas flow with an ejection speed of several hundred m/s is used.

Additionally, a device is being developed that uses an ultrasonic vibrator to generate microdroplets to be introduced into the ion source.

The following are conventional techniques that apply an atomization device using an ultrasonic vibrator to an ion source.

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

Patent Document 2 discloses that in a mass spectrometry system, a sample having an ionic group and a liquid containing a protic polar solvent are atomized using an ultrasonic transducer, and the liquid is heated to remove the protic polar solvent. An ion generating device is disclosed that has a configuration.

Japanese Patent Application Publication No. 11-051902 Japanese Patent Application Publication No. 2015-031650

In a liquid chromatograph mass spectrometer, multiple types of liquid samples to be analyzed are continuously supplied from a liquid chromatograph through a thin tube with a diameter of several hundred μm or less. The amount of each liquid sample supplied is extremely small, several hundred μL or less. In the droplet generation device used in mass spectrometers, these liquid samples are continuously formed into microdroplets without mixing with each other, and the generated microdroplets are charged and the solvent is removed by heating. However, it is required to generate ions of solute components and continuously supply them to the analysis section.

The droplets formed by the ultra-high-speed gas flow of the gas spray used in the ion source are atomized at ultra-high speed, so the energy required for processes such as charging and heating vaporization is large, and the time required to perform these processes is large. Becomes shorter. Therefore, there is also a problem in terms of stabilizing these processes.

In addition, because the liquid sample is turned into minute droplets in a high-speed, large-volume gas flow, the sample droplets that can be introduced into the mass spectrometer are only a small portion of the supplied liquid sample, and the majority of the sample droplets can be introduced into the mass spectrometer. will be disposed of without being used.

The devices described in Patent Documents 1 and 2 do not provide a solution to the loss of microdroplets in the path that sends the generated mist-like microdroplets to the analyzer.

The purpose of the present disclosure is to generate micro droplets from a liquid sample continuously supplied from a liquid chromatograph, etc., apply a charge to the micro droplets, and perform a series of processes to vaporize the solvent using a small gas flow rate. Another object of the present invention is to provide a new ion source that introduces ions of solute components contained in a liquid sample into an analysis block.

The ion source of the present disclosure supplies ions of a solute component to an analysis block that analyzes a liquid sample containing a solute component, and includes a droplet generation section that generates droplets of the liquid sample, and a droplet generation section that generates droplets of the liquid sample. The heating and pressure regulating gas supply block is equipped with a heating and pressure regulating gas supply block that heats the transport gas that flows in with droplets, and a charge applying section that imparts an electric charge to the solute component and ionizing it. A sample transport pipe arranged between the droplet generating part, a heating and pressure regulating gas retention part having a configuration in which the sample transport pipe is in contact with the sample transport pipe so that heat can be transferred thereto, and a gas heating part that heats a predetermined gas to a predetermined temperature. and a pressure adjustment unit that maintains the pressure of a predetermined gas within a predetermined range, the droplets and the transport gas are heated by the heated predetermined gas, and the sample transport pipe includes a droplet generation The liquid droplets and the transport gas are supplied from the heating and pressure regulating gas retention section, and a predetermined heated gas is introduced from the heating and pressure regulating gas retention section.

According to the present disclosure, a series of processes in which micro droplets are generated from a liquid sample continuously supplied from a liquid chromatograph or the like, an electric charge is imparted to the micro droplets, and a solvent is vaporized are performed with a small gas flow rate. However, it is possible to provide a new ion source that introduces ions of solute components contained in a liquid sample into the analysis block.

FIG. 2 is a cross-sectional view of a main part of an analysis device according to an example. 2 is a front view showing the liquid flow path plate 2 of FIG. 1. FIG. 2A is a sectional view showing a state in which the liquid flow path plate 2 of FIG. 2A is installed in an ion source. FIG. FIG. 2B is a partially enlarged view showing the micropore forming portion 2d of FIG. 2A. FIG. 3B is a vertical cross-sectional view of the portion shown in FIG. 3A. FIG. 2 is a cross-sectional view showing the heated and pressure-regulated gas supply block 11 of FIG. 1. FIG. FIG. 2 is a cross-sectional view showing the charge imparting block 21 of FIG. 1. FIG. 2 is a partial cross-sectional view of the charge applying block 21 seen from the analysis block 25 side of FIG. 1. FIG. FIG. 7 is a cross-sectional view showing another charge applying section in the example. 6A is a sectional view of the sample transport tube 13 of FIG. 6A viewed from the heating and pressure regulating gas supply block 11 side. FIG.

The present disclosure relates to an ion source for ionizing components contained in a liquid sample to be analyzed in an analyzer such as a liquid chromatograph mass spectrometer and introducing the ion source into an analysis block, and an analyzer equipped with such an ion source. Regarding.

Examples according to the present disclosure will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the main parts of the analysis device of the example.

The analysis device shown in this figure includes a liquid sample atomization block 1 (droplet generation section), a heating and pressure regulating gas supply block 11, a charge application block 21, and an analysis block 25. These are connected in series. Of these, the liquid sample atomization block 1, the heating and pressure regulating gas supply block 11, and the charge imparting block 21 constitute an ion source. The ion source is connected to an analysis block 25 via a connection block 22 with a capillary connection 23 . The inside of the analysis block 25 is kept in a substantially vacuum state (depressurized state).

The liquid sample atomization block 1 includes a thin liquid flow path plate 2 and an ultrasonic vibration application 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 part 10a and a flange-like member 10b. The holder main portion 10a has a substantially cylindrical shape. The liquid channel 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 bolted Langevin type transducer (BLT) that includes a tip vibrating section 3a, a piezoelectric element section 3b, and a screw housing 3c (piezoelectric element fixing body). An ultrasonic vibration applying unit 3 and a rectifying plate 4 are inserted and fixed inside the main part 10a of the holder. The main part 10a of the holder is inserted into a through hole of the liquid sample supply side member 9a.

The ultrasonic vibration imparting unit 3 is arranged so as to be in contact with the liquid flow path plate 2, and applies pressure to the liquid flow path plate 2 by pushing a flange-like member 10b attached to the main part 10a of the holder with a spring 7 (pressing member). The tip vibrating section 3a of the ultrasonic vibration imparting unit 3 is configured to be in close contact with each other.

A supply pipe 5 and a discharge pipe 8 are connected to the liquid sample supply side member 9a. The 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 has not been atomized is discharged from the discharge pipe 8 as the remaining sample liquid 26c.

A conveying gas supply pipe 6 is connected to the flange-like member 10b, so that the conveying gas 27a is supplied to the inside of the main part 10a of the holder. The transport gas 27a has a substantially uniform flow velocity distribution due to the rectifying plate 4, passes around the ultrasonic vibration applying unit 3, and is supplied to the heating and pressure regulating gas supply block 11 together with droplets generated in the liquid channel plate 2. be done. By passing the transport gas 27a through the side surface of the ultrasonic vibration applying unit 3, the ultrasonic vibration applying unit 3 can also be cooled.

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

A heat insulating/insulating member 14 is sandwiched between the outer tube 12a and the sample transport tube 13. Since the heat insulating/insulating member 14 is difficult to conduct heat, the liquid sample atomization block 1 is prevented from being heated by the heat of the high temperature heating and pressure regulating gas supply block 11. Furthermore, since the heat insulating/insulating member 14 has electrical insulation properties, it also has the function of blocking the current from the charge imparting block 21 .

In the sample transport tube 13, the micro droplets 26b flow together with the transport gas 27b. The micro droplets 26b and the transport gas 27b are supplied into the inner tube 12b.

The air heater 16 heats a predetermined flow rate of gas to a predetermined temperature and supplies it to the outer shell chamber 18 as heated gas 27c. Note that in this embodiment, nitrogen gas is used as the gas supplied to the outer shell chamber 18. In addition to nitrogen, the gas used in this case is preferably an inert gas such as argon or helium.

The pressure within the outer shell chamber 18 is regulated by the pressure regulating means 17, and when the pressure exceeds a predetermined value, an exhaust gas flow 27g is generated.

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

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

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

In addition, the internal area including the heating and pressure regulating gas supply block 11 from the liquid flow path plate 2 to the connection block 22 is designed to prevent the carrier gas flow from leaking from the central pipe line. It has an airtight structure including the terminals.

The solute particles 26d sent to the analysis block 25 are subjected to component analysis processing in the analysis block 25 as ionized solute components 27f.

FIG. 2A is a front view showing the liquid flow path plate 2 of FIG. 1.

The liquid flow path plate 2 has a liquid flow path 2g inside thereof. A liquid sample supply port 2f and a discharge port 2h are provided at the end 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 through holes 2e for carrier gas are provided around the micropore forming portion 2d.

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

The liquid flow path plate 2 has a structure in which three

thin plates

2a, 2b, and 2c are laminated and bonded. A supply port 2f and a discharge port 2h for the sample liquid 26a are formed in the thin plate 2c on the side to which the sample liquid 26a is supplied. Both the supply port 2f and the discharge port 2h are through holes. An elongated hole is formed in the central thin plate 2b. This hole constitutes a liquid flow path 2g in a state where three

thin plates

2a, 2b, and 2c are laminated. A microhole forming portion 2d in which a plurality of microholes (through holes) are formed is provided in the center of the thin plate 2a. This fine hole communicates the liquid flow path 2g with the outer surface of the thin plate 2a.

In this embodiment, 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 were stacked and integrated by diffusion bonding to form a liquid channel plate 2 with a thickness of 150 μm. Since diffusion bonding is a bonding method that does not use an adhesive or the like, it is also possible to flow a liquid sample containing a solvent or the like through the liquid flow path plate 2.

The liquid channel plate 2 is sandwiched between the liquid sample supply side member 9a and the connection member 9b. The liquid sample supply side member 9a and the connection member 9b each have a recessed portion in the center so that they do not 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 connection member 9b sandwich the peripheral edge of the liquid flow path plate 2 and support the liquid flow path plate 2.

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

The liquid sample supply side member 9a is provided with 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. A 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 channel 2g in the liquid channel plate 2. A part of the sample liquid 26a is caused by the ultrasonic vibration in the thickness direction of the liquid flow path plate 2 applied from the tip vibrating part 3a of the ultrasonic vibration applying unit 3 to a part of the sample liquid 26a. It is released from the fine holes of the hole forming part 2d, becomes minute droplets 26b, and is sent to the left in the figure together with the transport gas 27b that has passed through the transport gas through-hole 2e of the liquid flow path plate 2. The transport gas 27b flows to surround the flow of the micro droplets 26b. In other words, the minute droplets 26b flow in the center of the channel, and the transport gas 27b flows in the outer periphery of the channel.

The remainder of the sample liquid 26a passes through the discharge port 2h and is discharged as a remaining sample liquid 26c.

With this structure, even if the type of sample liquid 26a that is continuously supplied is changed, the sample liquid 26a flowing through the liquid flow path 2g will not mix, and the type of sample liquid 26a will change. Continuous formation of micro droplets is realized in response to the switching of the droplets.

Since the minute droplets 26b flow while being surrounded by the transporting gas 27b, they are stably transported toward the heating and pressure regulating gas supply block 11 as shown in FIG.

FIG. 3A is a partially enlarged view showing the micropore forming part 2d in FIG. 2A.

In FIG. 3A, a large number of micropores provided in the micropore forming portion 2d are shown in a dotted manner. Further, the liquid flow path 2g inside the liquid flow path plate 2 and the tip vibrating portion 3a that is in contact with the back surface of the liquid flow path plate 2 are shown by dotted lines.

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

In FIG. 3B, a configuration in which three

thin plates

2a, 2b, and 2c are stacked, a tip vibrating section 3a in contact with the thin plate 2c, and a large number of micropores in a micropore forming section 2d formed in the thin plate 2a are shown. It is shown. In other words, the tip vibrating section 3a of the ultrasonic vibration imparting unit 3 is in contact with the opposite surface of the liquid flow path plate 2 where the micropore forming section 2d is provided.

The diameter of the microdroplet 26b shown in FIG. 2B is influenced by the ultrasonic vibration frequency and the diameter of the micropore. In this example, in order to form minute droplets 26b of approximately several micrometers, the frequency of the ultrasonic vibration was set to about 150 kHz, and the diameter of the narrowest part of the micropores was set to 4 micrometers. As a result, droplets with a diameter of 4 to 6 μm could be formed. There were almost no droplets with a diameter of 10 μm or more, and no droplets with a diameter of 20 μm or more were observed.

From this experimental result, in order to form microdroplets of approximately several μm in size, it is necessary to excite at a frequency of approximately several hundred kHz and to form micropores with a narrowest diameter of several μm or less. I understand.

In addition, methods such as laser machining and electroforming can be used to form such micropores, but in this example, the number of micropores is large, stainless steel was selected as the material, and took cost into consideration and used YAG laser processing.

In many processing methods, such micromachining results in a difference in hole diameter in the thickness direction. In the microhole processing using the YAG laser in this example, when a microhole with a diameter of 4 μm was formed, the diameter of the hole on the irradiation side was about several tens of μm. In the thin plate 2a of this embodiment, the diameter of the micropores on the surface side is approximately 4 μm. This is because, as a result of study, it was found that the larger the diameter on the channel side and the smaller the diameter on the surface side, the easier the liquid would be released in the form of mist, and the more difficult it would be for liquid beads to form on the surface of the channel plate. If liquid beads occur on the surface side of the channel plate, the liquid discharge becomes unstable.

Further, since the micro droplet 26b shown in FIG. 2B has a slow initial velocity and a small droplet diameter, stable transport of the micro droplet 26b can be achieved even when the flow rate of the transport gas 27b is small.

In this embodiment, 1 L/min of nitrogen gas is used as the transport gas 27b, and the micro droplets 26b are stably transported within the sample transport tube 13 shown in FIG. 1 at a transport speed of about 1 m/s. .

Note that in this embodiment, the droplet generation section has a liquid flow path plate 2 that is a plate-like member, but the droplet generation section according to the present disclosure is not limited to this. A structure in which a liquid flow path is formed inside the piping may also be used.

Further, in this embodiment, the droplet generation unit is configured to generate droplets using the ultrasonic vibration imparting unit 3, but the droplet generation unit according to the present disclosure is not limited to this. The structure may be such that droplets are generated by a gas spray method or the like.

FIG. 4 is a sectional view showing the heating and pressure regulating gas supply block 11 of FIG. 1.

FIG. 4 shows a cross section passing through the central axes of the air heater 16 and the pressure regulating means 17, and the direction in which the micro droplets 26b shown in FIG. 1 are conveyed is perpendicular to the drawing.

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

The volume of gas changes significantly when it is 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, the pressure regulating means 17 is arranged in the outer shell chamber 18, so that even if the volume of the heated gas supplied from the air heater 16 changes, the pressure inside the outer shell chamber 18 does not change. did. The pressure regulating means 17 of this embodiment utilizes a component that opens a valve when the internal pressure reaches a predetermined pressure. By providing the pressure regulating means 17, when the pressure of the airflow 27h supplied from the air heater 16 into the outer tube 12a rises to a predetermined value, part of the gas in the outer shell chamber 18 is removed from the pressure regulating means 17. It is discharged. Thereby, it is possible to maintain the pressure of the heated gas in the outer shell chamber 18 constant.

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 inside of the inner tube 12b, and swirls around the inner tube 12b to envelop the minute droplets 26b and the carrier gas 27b that are transferred from the sample transfer tube 13 shown in FIG. flow inside.

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

This is due to the following reasons.

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 transporting gas 27b containing the minute droplets 26b. When the gas flow rate increases, the flow path length is adjusted in consideration of the distance required for the swirling airflow 27d and the transport gas 27b containing the microdroplets 26b to mix, and the time required for the solvent of the microdroplets 26b to vaporize. need to be made longer.

If the flow path is lengthened, not only will the device become larger, but the possibility that the minute droplets 26b and their solute components contained in the transport gas 27b will come into contact with the inner wall surface of the inner tube 12b increases. The solute components contained in the minute droplets 26b to be analyzed are burned out when they come into contact with the inner wall surface of the high-temperature inner tube 12b.

Burning out solute components is effective in preventing contamination with components contained in other liquid samples sent later, but the problem is that the amount of solute components that can be introduced into the analysis block is reduced. occurs.

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

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 regulating means 17, so that the swirling airflow 27d and the transporting gas 27b are This suppresses changes in airflow caused by the merging of air.

Furthermore, by making the swirling airflow 27d supplied to the inner tube 12b a gentle flow so that it swirls around and wraps around the transport gas 27b, more solute components can be introduced into the analysis block.

In this way, by supplying the heated gas to the inner tube 12b after adjusting the pressure, the pressure of the inner tube 12b is also maintained within a predetermined range, and in this state, the solvent contained in the micro droplets 26b is heated and vaporized. Can be done.

Next, the charge applying section of this embodiment will be explained.

FIG. 5A is a cross-sectional view showing the charge applying block 21 of FIG. 1.

The configuration shown in FIG. 5A is shown in FIG. 1, so its description will be omitted here.

FIG. 5B is a partial cross-sectional view of the charge applying block 21 seen from the analysis block 25 side in FIG. 1.

Both FIGS. 5A and 5B show a cross section including a position where the discharge wire 20 is stretched.

In FIG. 5B, the connection block 22 is shown as viewed from the front. A capillary connection portion 23 (microhole) connected to the analysis block is provided in the center of the connection block 22. The inner diameter (diameter) of the capillary connecting portion 23 is desirably one-fifth or less of the inner diameter of the downstream end of the sample transport channel, and more desirably one-tenth or less. In terms of actual dimensions, the inner diameter of the capillary connecting portion 23 is preferably 1 mm or less, more preferably 100 μm or less.

A discharge wire 20 is stretched across the conduit hole provided in the center of the charge applying block 21. The charge applying block 21 is made of an insulating material. A spring 19 and a power supply terminal for tensioning the discharge wire 20 are arranged.

A high voltage power source 28 is connected to the discharge wire 20. By applying a high voltage to the discharge wire 20 by the high voltage power supply 28, a potential difference is applied between the discharge wire 20 and the connection block 22, and corona discharge is generated. Positive ions and electrons generated by corona discharge can impart charges to solute components in the carrier gas. The current and polarity of the high voltage power supply 28 are controlled according to the solute components.

The carrier gas 27e containing the charged solute component is supplied to the inside of the casing 24 as a solute component 27f through the capillary connection section 23 provided in the connection block 22. The inside of the casing 24 is maintained in a substantially vacuum state, and the amount of the carrier gas 27e passing through the capillary connection portion 23 is affected by the pressure of the carrier gas 27e in the carrier conduit.

In this embodiment, by adopting a structure in which the pressure and flow rate of the carrier gas 27e in the carrier pipeline stably meet predetermined conditions, almost all of the carrier gas 27e containing solute components (ions) in the carrier pipeline is removed. It can be supplied inside the casing 24. In order to realize this, a pressure regulating means 17 is provided in the heating and pressure regulating gas supply block 11.

Next, an example of setting conditions in this embodiment will be explained.

Under conditions where the outside air pressure is approximately atmospheric pressure, the amount of carrier gas 27e passing through the thin tube connection portion 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 heating and pressure regulating gas supply block 11 is set to approximately 6 L/min. . As an example of an actual setting, slightly more heated gas than about 6 L/min is supplied from the air heater 16 to the outer shell chamber 18 of the heating and pressure regulating gas supply block 11, and the leak pressure of the pressure regulating means 17 is set to 1 atm ( (atmospheric pressure).

With this setting, the pressure of the carrier gas 27e flowing through the pipe becomes approximately atmospheric pressure, and only the amount that can be balanced with the amount of the carrier gas 27e passing through the thin tube connection part 23 of the connection block 22 is heated. The gas is supplied from the outer shell chamber 18 of the pressurized gas supply block 11 to the inner pipe line as a swirling airflow 27d.

In the structure of this embodiment, as described above, it is possible to stably introduce all of the gas flow containing the sample liquid atomized in the liquid sample atomization block 1 and the gas flow for heating and vaporizing it into the analysis block. It is possible. This allows solute components contained in many liquid samples to be introduced into the analysis block, making it possible to significantly improve the sensitivity of the analyzer.

Next, other charge applying parts in this embodiment will be explained.

As described above, the charge imparting section shown in FIGS. 5A and 5B evaporates the solvent component of the droplet sample in the heating and pressure regulating gas supply block 11, and then irradiates the solute component with corona ions in the charge imparting block 21. It ionizes.

In the ion source of current mass spectrometers, in addition to the charge imparting block 21 shown in FIGS. 5A and 5B that imparts a charge to the solute component after completely vaporizing the solvent component, the ion source of the current mass spectrometer also charges the solute component by completely vaporizing the solvent component. A method of imparting a charge to is also used. These methods are called atmospheric pressure chemical ionization (APCI) and electrospray (ESI), respectively. These two methods have different analytical sensitivities depending on the molecular weight and other characteristics of the solute component to be analyzed, so they are used differently depending on the type of solute component.

In this example as well, it is desirable to provide a charge applying unit that applies an electric charge to the droplet immediately after the formation of micro droplets, in addition to the charge applying unit shown in FIGS. 5A and 5B that applies an electric charge to the solute component after solvent vaporization.

FIG. 6A is a cross-sectional view showing another charge applying section in this example.

In this figure, a charge applying section is arranged in the sample transport tube 13, which is the inlet of the heating and pressure regulating gas supply block 11 shown in FIG. 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 connection member 9b is made of an insulating material. Further, the sample transport tube 13 is made of a conductive material, and is connected to the heating and pressure regulating gas supply block 11 side via a heat insulating/insulating member 14 .

A variable power source 29 capable of applying both positive and negative polarities for applying voltage was arranged between the sample transport tube 13 and the liquid sample supply side member 9a. The liquid sample supply side member 9a is in electrical contact with the liquid flow path plate 2. Thereby, an electric field can be generated between the surface of the liquid flow path plate 2 from which sample droplets are discharged and the sample transport tube 13.

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

FIG. 6B is a sectional view of the sample transport tube 13 in FIG. 6A viewed from the heating and pressure regulating gas supply block 11 side.

In FIG. 6B, as an electrode for generating an electric field on the surface of the liquid flow path plate 2, an electric wire 61 is arranged not on the wall surface of the sample transport tube 13 but within the flow path of the sample transport tube 13. Three electric wires 61 are provided in a Y-shape (radially) at intervals of 120 degrees.

As a result, the direction of the electric field generated on the surface of the liquid flow path plate 2 more closely matches the direction of the transport gas 27b flowing inside the sample transport tube 13. This stabilizes the traveling direction of the charged microdroplet 26b, prevents the microdroplet 26b from colliding with the wall surface of the sample transport tube 13, and reduces the amount of the microdroplet 26b lost. Can be done. As a result, more micro droplets 26b are supplied to the heating and pressure regulating gas supply block 11 side.

When applying an electric charge to the micro droplets 26b discharged from the liquid flow path plate 2 in a state containing a solvent using the configuration shown in FIGS. 6A and 6B, it is not necessary to apply an electric charge using the corona ions shown in FIGS. 5A and 5B.

By controlling to switch between charge application by corona ions shown in FIGS. 5A and 5B and charge application during droplet formation shown in FIGS. 6A and 6B, two types of charge application means can be selected in one ion source and appropriate. can be implemented.

As explained above, the ion source of the present disclosure can suppress and appropriately control the amount of the gas flow for transporting minute droplets and the heated gas flow for vaporizing the solvent. Therefore, the analyzer 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, and the sensitivity of the analyzer can be significantly improved.

According to the present disclosure, it is possible to provide a new ion source that can introduce many of the generated solute component ions into a mass spectrometer, and to provide a mass spectrometer with high analysis sensitivity using the ion source.

Hereinafter, preferred embodiments according to the present disclosure will be collectively described.

In the ion source, the droplet generation section includes an ultrasonic vibration application unit, and has a configuration in which droplets are generated by the ultrasonic vibration application unit.

The droplet generating section has a liquid flow path formed inside a pipe or a plate-like member, and the pipe or plate-like member has micropores communicating the outside and the liquid flow path, and The application unit is configured to apply ultrasonic vibrations to the liquid sample flowing through the liquid channel, and droplets are ejected from the micropores.

The droplet generation section has a configuration in which droplets flow into the center of the sample transport channel, and transport gas flows into the sample transport channel so as to surround the flow of the droplets.

The predetermined gas introduced from the heating and pressure regulating gas retention section into the sample transport pipe has a configuration in which it flows in so as to surround the droplets and the flow of the transport gas.

The sample transport channel has a wider cross-sectional area on the downstream side of the position where the predetermined gas flows in than on the upstream side. When the cross section of the sample transport conduit is circular, the inner diameter of the cross section of the flow path is larger on the downstream side than on the upstream side on the downstream side of the position where the predetermined gas flows.

The charge applying section is configured to be placed between the analysis block and the heating and pressure regulating gas supply block.

The charge applying section is arranged between the heating and pressure regulating gas supply block and the droplet generating section.

The analysis device includes an ion source and an analysis block.

The ion source and the analysis block are connected by a capillary connection, and the ionized solute component is supplied to the analysis block through the capillary connection.

1: Liquid sample atomization block, 2: Liquid channel plate, 2a, 2b, 2c: Thin plate, 2d: Fine hole forming section, 2e: Through hole for carrier gas, 2f: Supply port, 2g: Liquid channel, 2h : Discharge port, 3: Ultrasonic vibration imparting unit, 3a: Tip vibrating section, 3b: Piezoelectric element section, 3c: Screw housing, 4: Current plate, 5: Supply piping, 6: Conveying gas supply piping, 7: Spring, 8: Discharge piping, 9 Holding body, 9a: Liquid sample supply side member, 9b: Connection member, 10: Holding body, 10a: Main part of holding body, 10b: Flange-like member, 11: Heating and pressure regulating gas supply block , 12: Main body of heating and pressure regulating gas supply unit, 12a: Outer tube, 12b: Inner tube, 13: Sample transport tube, 14: Heat insulation/insulating member, 15: Mesh plate, 16: Air heater, 17: Pressure regulating means, 18 : Outer shell chamber, 19: Spring, 20: Discharge wire, 21: Charge imparting block, 22: Connection block, 23: Capillary connection part, 24: Housing, 25: Analysis block, 26a: Sample liquid, 26b: Microfluid drop, 26c: remaining sample liquid, 26d: solute particles, 27a, 27b: transport gas, 27c: heating gas, 27d: swirling air flow, 27e: transport gas, 27f: solute component, 27g: exhaust gas flow, 27h: air flow , 28: High voltage power supply, 29: Variable power supply, 61: Electric wire.

Claims

An ion source that supplies ions of solute components to an analysis block that analyzes a liquid sample containing solute components,
a droplet generation unit that generates droplets of the liquid sample;
a heating and pressure regulating gas supply block that heats the transport gas that flows in from the droplet generating section with the droplets;
a charge imparting unit that imparts a charge to the solute component and ionizes the solute component;
The heating and pressure regulating gas supply block is
a sample transport conduit arranged between the analysis block and the droplet generation section;
a heated and pressure-regulated gas retention section configured to be in contact with the sample transport conduit in a heat-transferable manner;
a gas heating section that heats a predetermined gas to a predetermined temperature;
a pressure adjustment unit that maintains the pressure of the predetermined gas within a predetermined range;
The droplets and the transport gas are heated by the heated predetermined gas,
The sample transport conduit is configured such that the droplets and the transport gas are supplied from the droplet generation section, and the predetermined heated gas is introduced from the heating and pressure regulating gas retention section. There is an ion source.
The droplet generation unit includes an ultrasonic vibration applying unit,
The ion source according to claim 1, wherein the droplet is generated by the ultrasonic vibration applying unit.
The droplet generation section has a liquid flow path formed inside a pipe or a plate-like member,
The piping or the plate-like member has a fine hole that communicates the outside with the liquid flow path,
The ultrasonic vibration applying unit is configured to apply ultrasonic vibration to the liquid sample flowing in the liquid flow path,
3. The ion source of claim 2, wherein the droplets are ejected from the micropores.
The droplet generating section has a configuration in which the droplets flow into the center of the sample transport pipe, and the transport gas flows into the sample transport pipe so as to surround the flow of the droplets. Item 1. Ion source according to item 1.
The ion source according to claim 1, wherein the predetermined gas introduced from the heating and pressure-adjusted gas retention section into the sample transport conduit is configured to flow in so as to surround the droplets and the flow of the transport gas. .
The ion source according to claim 5, wherein the sample transport pipe has a wider cross-sectional area on the downstream side of the position where the predetermined gas flows in than on the upstream side.
The ion source according to claim 1, wherein the charge applying section is configured to be arranged between the analysis block and the heating and pressure regulating gas supply block.
The ion source according to claim 1, wherein the charge applying section is arranged between the heating and pressure regulating gas supply block and the droplet generating section.
An ion source according to any one of claims 1 to 8,
An analysis device comprising the analysis block.
The ion source and the analysis block are connected by a capillary connection,
The analyzer according to claim 9, wherein the ionized solute component is supplied to the analysis block through the capillary connection.