JP3379510B2 - Liquid chromatograph coupled mass spectrometer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid chromatograph coupled mass spectrometer for mass spectrometric analysis of effluent from a liquid chromatograph.

[0002]

2. Description of the Related Art A mass spectrometer (hereinafter abbreviated as MS) is a highly sensitive analyzer that gives information on the molecular weight and structure of organic compounds. for that reason,
It has become an indispensable analyzer in the fields of organic chemistry, pharmacy and biochemistry. However, MS could not separate and identify the constituent components of the mixture, and the analysis was difficult when the mixture was the analysis target. Therefore, using a liquid chromatograph (Liquid Chromatograph, hereinafter abbreviated as LC), which is excellent in separating and identifying a mixture,
A liquid chromatograph for binding analysis of non-volatile substances, thermolabile substances, inorganic compounds, organic compounds, low-molecular substances, and high-molecular substances that can be easily analyzed if they are soluble in a solvent. Directly connected mass spectrometer (LC / M
Abbreviated as S. ) Was devised.

LC is a device for dissolving a sample to be analyzed in a solvent and separating the components of this solution under atmospheric pressure.
On the other hand, MS is an apparatus for analyzing a sample ionized under high vacuum. Therefore, to combine these,
Solvent must be removed from the LC effluent (desolvation) and the desolvated residual sample must be ionized and fed to the mass spectrometer under high vacuum. The technique for coupling LC and MS is described in, for example, Japanese Patent Publication No. 58-43692. According to this technique, the effluent from the LC is atomized, the mist is desolvated and ionized, and the ionized sample (desolvated effluent) is subjected to mass spectrometry.

[0004]

When the effluent from the liquid chromatograph is atomized, the jet stream spreads like a spray, but relatively large droplets of mist gather near this central portion, In addition, relatively small droplets of fog collect near the periphery. As these fogs move, large droplets near the center have a large mass and a large kinetic energy, so they are not much affected by air or the like. Therefore, the vaporization does not occur so much, and the droplet diameter does not become so small. On the other hand, the mist of small droplets near the periphery has a small mass and a small kinetic energy, and therefore is directly affected by air and the like. Therefore, the droplet diameter is gradually reduced by repeated collisions with the fluid resistance and other droplets. When the droplet size becomes small in this way, it is greatly affected by air etc., and
Since the movement speed is slow, the time to be affected becomes long. As a result, small droplets in the vicinity of the periphery are increasingly promoted to vaporize, resulting in a smaller droplet diameter.

As described above, when the effluent from the liquid chromatograph is atomized, the fog of large liquid droplets near the center does not change its droplet diameter as it moves, while the mist of large liquid droplets near the center is small. The mist of droplets makes the droplet diameter smaller and smaller. Therefore, as a whole, the variation in the droplet diameter increases.

A technique is also known in which the effluent (sample, solvent, mixed solution) from the atomized chromatograph is further miniaturized and the solvent is removed. A heating method, which has a simple structure, is often used for the miniaturization of droplets. That is,
The vaporizer heats the droplets. The vaporizer is made of a metal block with a built-in heater so that it can be heated almost uniformly. For example, the vaporizer is like a quartz tube around which a heater wire is wound. The ejected spray stream (effluent from the chromatograph) is heated by radiant heat from the vaporizer while passing through the vaporization space surrounded by the vaporizer. The peripheral flow of the spray flow has a lower moving speed due to friction with the wall surface than the central flow, and since it is closer to the wall surface of the vaporizer, more heat can be supplied. That is, the droplets in the peripheral portion absorb infrared rays emitted from the surrounding wall surface,
The evaporation of the liquid from the surface of the droplet is greatly promoted, and the atomization of the droplet is promoted. Most of the infrared rays are consumed by the atomization of the surrounding mist and do not reach the center of the mist, and the droplets in the center cannot be heated sufficiently. Therefore, the diameter of the liquid droplet in the peripheral portion is originally small due to the spraying and diffusion, and the diameter of the liquid droplet in the peripheral portion rapidly decreases due to the absorption of more radiation heat. On the contrary, droplets having a large diameter are concentrated in the central portion. Therefore, the distribution width of the droplet diameter in the spray flow becomes larger while moving in the vaporization space than when the mist was generated. That is, even in the case of miniaturization by the heating method, fine mist is gathered in the peripheral part, and more mist having a large diameter is present in the central part, and the dispersion of the droplet diameter is rather large.

[0007] Here, from the viewpoints of application area and stability of the LC / MS interface, among atmospheric pressure ionization, particularly atmospheric pressure chemical ionization (Atmospheric Pressu
reChemical Ionization, hereinafter abbreviated as APCI. ) Has attracted attention and has become widely used. Regarding APCI, for example, Analytical Chemistry (An
alytical Chemistry), Vol.62, No.13 (199
0) P713A-P725A and Journal of Chromatogr
aphic Science). Vol.29 (1891) P357-3
66. In APCI, the effluent (mixture of sample and solvent) from a liquid chromatograph is atomized under atmospheric pressure, and this mist is further subjected to high voltage corona discharge of about 3 to 5 kV (corona discharge needle electrode). Expose. Thereby, first, the solvent molecules are ionized. The generated ions then repeat the ion molecule reaction with the sample molecule,
Finally, the sample molecules are ionized. The ionized sample is introduced into a mass spectrometer under high vacuum and mass analyzed.

The effluent from the liquid chromatograph is atomized and supplied to the vicinity of the corona discharge needle electrode, but if there is a large variation in the droplet diameter of the mist as described above, a complicated flow is created. Therefore, the flow of fog around the corona discharge needle electrode constantly changes. As a result, the ion molecule reaction becomes unstable, and the ionized sample cannot be stably supplied to the mass spectrometer.

Also in APCI, heating the mist of the effluent of the liquid chromatograph to make it fine is effective for promoting the subsequent ionic molecule reaction. However, in this case, as described above, a large difference in density (dispersion of droplet diameter) and a difference in temperature occur in the spray flow. When the jet flow with this temperature difference is supplied near the needle electrode for corona discharge,
The temperature around the needle electrode for corona discharge constantly changes, and the ion-molecule reaction also becomes unstable. Therefore, the ionized sample cannot be stably supplied to the mass spectrometer, and high-sensitivity analysis becomes impossible.

The object of the present invention is to stabilize the mist of the effluent supplied from the liquid chromatograph to the corona discharge needle electrode,
This stabilizes the ionic molecule reaction between the sample and the solvent and enables highly sensitive LC / MS measurement.

[0011]

[Means for Solving the Problems] To achieve the above object
The feature of the present invention is that the effluent from the liquid chromatograph is
The spray part to spray and the spray flow from the spray part
And an exhaust passage communicating with the communication passage.
A heating part that performs heat and a needle-shaped electrode that directs the spray flow from the heating part.
Ionization part that is ionized by the corona discharge of
Ions generated in the ionization section are guided through the pores
Liquid chromatographic coupling with mass spectrometer for quantitative analysis
Between the heating unit and the ionization unit
A partition wall having a through hole, and the through hole is
It is formed at a position deviated from the central axis of the passage .

[0012]

According to the above construction, the peripheral flow of the spray flow having a high abundance ratio of fine droplets and high temperature can be selectively taken into the atmospheric pressure ion source and ionized. In addition, the generated ions (including cluster ions) are taken into the intermediate pressure portion, and the solvent is efficiently desolvated by accelerated collision dissociation due to the ion drift voltage.

The fact that the temperature is as high as possible alleviates the cooling due to adiabatic expansion and makes desolvation effective. As a result, chemical noise derived from cluster ions can be significantly reduced, and a highly sensitive distribution is possible. Further, even if the composition of the solvent changes momentarily by gradient analysis or the like, only the peripheral portion where the solution is miniaturized is ionized and taken in, so that desolvation in the intermediate pressure chamber is efficiently performed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 shows an LC / M according to an embodiment of the present invention.
It is explanatory drawing which shows S (including interface). FIG. 2 shows an enlarged view of the atomizer and vaporizer parts. 1 and 2, 1 is a mobile phase for separating sample components, 2
Is a pump, 3 is a sample inlet for injecting a sample solution, 4 is an analytical column, 6 is a sprayer, 7 is a spray space at atmospheric pressure, 8 is a vaporizer, 81 is a heater, 82 is a spiral insertion rod, and 9 is a vaporizer. Space, 10 are needle electrodes for corona discharge to which high voltage is applied, 1
1 is an atmospheric pressure chemical ion source part, 14 is a first pore for ion sampling, 15 is an intermediate pressure part, 16 is a second pore, 17 is a vacuum pump for exhausting the intermediate pressure part, 18 is a mass spectrometric part , 19 is a detector, 20 is a DC amplifier, 21 is a data processing unit, 22 is a vacuum pump for exhausting the mass analysis unit,
Reference numeral 30 denotes the central axis of the spray flow, and 31 denotes the peripheral flow of the spray flow.

In FIG. 1, the mobile phase 1 (solvent) stored in the mobile phase tank is sent out by a pump 2. The sample solution is injected from the sample injection port 3 with a microsyringe,
The continuously flowing mobile phase 1 is sent to the analytical column 4. The sample sent in is separated and eluted into each component in the analysis column 4. The eluted components are sent to the sprayer 6 via the pipe.

There are various types of atomizers. Here, an example of thermal spraying is shown in FIG. The sprayer 6 is composed of a metal capillary 61 having an inner diameter of about 0.1 mm, a heat block 62 surrounding the metal capillary 61, a heater 63, a temperature sensor 64 and the like. The metal capillary 61 of the atomizer 6 includes the heater 6
3 and a heating block 62, which is controlled by a temperature sensor 64, to heat. The eluate is sent to the metal capillary 61, heated to about 200 ° C. at once, and ejected as a mist from the tip of the metal capillary 61 into the atomizing space 7 at atmospheric pressure. This spray flow enters the vaporization space 9 of the heated vaporizer 8 while gradually diffusing through the spray space 7. During this diffusion, the surrounding area 3 is heated by the surroundings
Fine droplets are collected at 1, and more droplets having a large diameter are present at the central portion 30. The details of this phenomenon will be described later. Returning to FIG. 1 again, the fog that has passed through the vaporizer 8 enters the atmospheric pressure ion source unit 11. 3 to 5k here
The solvent molecules are first ionized by the corona discharge generated from the tip of the corona discharge needle electrode to which a high voltage of about V is applied. The generated ions then repeat the ion molecule reaction with the sample, and finally ionize the sample molecule. Ions are introduced into the intermediate pressure portion 15 from the first pores 14. At this time, the pressure changes from atmospheric pressure to medium vacuum, the ions are cooled, and cluster ions are generated. Where the first partition 1
The cluster ions are accelerated by the drift voltage V applied to 41 and the second partition 161, and collide with neutral molecules.
This collision is repeated many times, a part of the energy of this collision is taken in, and the ions are heated to desorb the added molecules (desolvation by collision dissociation). Uniform and fine droplets (cluster ions) are efficiently desolvated here. The desolvated bare ions enter the mass spectrometric section 18 through the second pores 16. Here, the mass dispersion is detected by the detector 19, and the mass spectrum is given by the data processor 21 through the DC amplifier 20.

The basic configuration of the LC / MS interface section of APCI will be described below.

The LC / MS interface section of APCI is mainly (1) spraying means, (2) atomizing means, (3)
Ionization means, (4) desolvation means for cluster ions,
(5) Consists of means for taking ions into the MS section. (1) Spray The solution (the effluent from the chromatograph / the mixture of the sample and the solvent) is sprayed in the spray space 7 at atmospheric pressure in the sprayer 6 with the help of gas flow, heating, ultrasonic vibration, and the like. Nebulization is a good way to stably transfer many thermolabile substances present in a liquid to the gas phase. Fog is a mixture of gas and liquid. Even if the mist is heated, heat is consumed by the heat of vaporization of the solvent until the mist is completely vaporized and becomes a gas, so the temperature of the mist does not rise. Therefore, there is an advantage that the thermolabile substance can be stably transferred to the gas phase. Analytical column 4
The eluate from is sent to the metal capillary 61 and suddenly 2
It is heated to about 00 ° C., and is ejected as a mist from the tip of the metal capillary 61 into the atomizing space 7 at atmospheric pressure. The mist passes through the spray space 7 and gradually diffuses into the heated vaporization space 9 of the vaporizer 8. Generally, the droplet diameter of the mist ejected from the metal capillary 61 is widely distributed from 100 μm to 1 μm. Since the diffusion speed of vaporized molecules and minute droplets is higher than that of relatively large droplets, as a result, many of these minute droplets are present in the peripheral portion 31 of the spray flow. On the contrary, large droplets exist near the central portion 30 of the spray flow. This state is shown in FIG. (2) Fine atomization A huge droplet of about 100 μm hinders ionization and causes chemical noise in the subsequent process.
Therefore, it is necessary that the large liquid droplets be sufficiently miniaturized before the ionization. A heating method, which has a simple structure, is often used for making the liquid droplets smaller. Further, this heating has an effect of reducing the degree of cooling due to adiabatic expansion in the intermediate pressure chamber 15. As shown in FIG. 2, the carburetor 8 is made of a metal block or the like containing a heater 81,
For example, the vaporizing space 9 having a diameter of 5 mm and a length of 50 mm can be heated almost uniformly. Further, as shown in FIG. 3, the vaporizer 8 may be a quartz tube 50 having a length of 50 mm and an inner diameter of about 5 mm, around which a heater wire 49 is wound. The vaporization space 9 is linearly formed so that the fog can smoothly reach the atmospheric pressure ion source 11. The spray flow ejected from the metal capillary 61 is heated by the radiant heat from the vaporizer 8 while passing through the vaporization space 9. Here, the peripheral flow 31 of the spray flow
Has a slower moving speed than the central flow 30 due to friction with the wall surface and is closer to the wall surface of the carburetor 9 and thus receives more heat. That is, the droplets in the peripheral portion 31 absorb infrared rays emitted from the surrounding wall surface, and the vaporization of the liquid from the surface of the droplets is promoted to a large extent to promote the miniaturization of the droplets. On the other hand, with respect to the central portion 30, most of the infrared rays are consumed by the atomization of fog in the peripheral flow and do not reach the central portion of the fog.
Droplets are not heated sufficiently.

As described above, the diameter of the liquid droplet in the peripheral portion is originally small due to the spraying and diffusion, and the diameter of the liquid droplet in the peripheral portion 31 is rapidly reduced due to the absorption of more radiation heat.
On the contrary, droplets having a larger diameter are concentrated in the central portion 30.
Therefore, the distribution width (dispersion) of the droplet diameter in the spray flow is
It becomes larger as it moves in the vaporization space 9 from the time of generation of fog. That is, the peripheral portion 31 has a high temperature and fine mist collects, and the central portion 30 has a low temperature and more fog with a large diameter exists. This state is shown in FIGS. 2 (a) and 2 (b). (3) Ionization The fine mist that has passed through the vaporizer 8 and the vaporized solvent molecules enter the atmospheric pressure ion source unit 11 in a mixed state.
Here, the solvent molecules are first ionized by the corona discharge generated from the tip of the corona discharge needle electrode 10 to which a high voltage of 3 to 5 kV is applied. The generated ions then repeat the ion molecule reaction with the sample molecule, and finally ionize the sample molecule. (4) Desolvation of cluster ions The generated ions are
The intermediate pressure portion 1 exhausted by the vacuum pump 17 from the first pore 14 opened near the center of the partition wall 141, which constitutes one wall surface of the atmospheric pressure ion source 11 and is provided on the opposite surface of the vaporizer 8.
Introduced in 5. The introduced ions are rapidly cooled by adiabatic expansion due to a sharp decrease in pressure, and form cluster ions to which polar molecules such as water are added. The cluster ions are accelerated by the ion drift voltage V applied between the partition walls 141 and 161, and repeatedly collide with neutral molecules. A part of the energy of this collision is taken inside and the cluster ions are heated to remove the added molecules. This is called desolvation by collision dissociation. The molecules having a small molecular weight that have entered the intermediate pressure chamber 15 diffuse and are exhausted by the vacuum pump 17. (5) Incorporation of ions into the MS part The desolvated ions are then used in the second pores 1 formed near the center of the partition wall 161.
The mass spectrometer 18 is entered from 6. Here, the mass dispersion is detected by the detector 19, and the mass spectrum is given by the data processor 21 through the DC amplifier 20.

Next, cluster ions and chemical noise will be described.

Chemical noise may appear on the mass spectrum in addition to the ions based on the sample. FIG. 4 shows an example of chemical noise appearing on the mass spectrum. Generally, the horizontal axis of the mass spectrum is the mass-to-charge ratio (m / z),
The vertical axis represents the ion current value. The peaks appearing at equal intervals from P1 to P6 on the mass spectrum are cluster ions. Assuming that the composition of the P1 ion is M and that water is added, the cluster ions of P2 to P6 are represented by (M + nH ₂ O). When water is used as the mobile phase M
Is H ₃ O m / z 19. Therefore, a large number of cluster ions of water may appear with high intensity for each m / z 18 like 19, 37, 55, 73 on the mass spectrum. Water molecules are added to the molecular ion Pm1 of the sample and Pm
2, Pm3 may appear.

In this case, since one ionic species Pm1 is dispersed in several ionic species, the original molecular ion Pm1
The ion current value of is low. In addition to these ions, ions are continuously detected over a wide mass range. This is considered to be cluster ions that have reached the detector without accurate mass analysis due to evaporation of additional molecules while the cluster ions are flying in the intermediate pressure chamber 15 and the mass spectrometric section 18. With the exception of the molecular ion Pm1 in the sample, these ions adversely affect the analysis and interfere with the discrimination of the molecular ion Pm1. These are collectively called chemical noise.

In order to suppress the appearance of these cluster ions, it is sufficient to thoroughly heat the fog before the ionization to completely vaporize the sample or the solvent, or to heat the entire interface. However, in atomizing means such as gas atomizing, heating atomizing, and ultrasonic atomizing which are currently used for atmospheric pressure chemical ionization, the diameter of mist droplets is widely distributed, for example, from about 100 μm to about 1 μm. Therefore, if it is attempted to vaporize a large-diameter droplet by heating at all, the small-diameter droplet will continue to receive heat for a long time after vaporization. This excessive heating causes thermal decomposition of the sample molecules, and the molecular weight and structural information of the sample are all lost, making it practically impossible to perform analysis as LC / MS.

As described above, the cluster ions hinder the grasp of the molecular weight and increase the chemical noise, thus hindering the analysis. However, on the other hand, a large number of molecules such as water added to molecules or ions are prevented from directly transmitting the influence of heat from the surroundings to the molecules or ions, and are effective in preventing thermal decomposition. Further, the applied heat is consumed for vaporization of the additional molecules from the cluster ions and the droplets, which hinders the temperature rise of the molecules or ions and prevents thermal decomposition. Fog is a mixture of droplets and gas. Therefore, even if the mist is heated, the heat is consumed by the vaporization of the solvent from the surface of the droplet, and the temperature of the mist does not rise. As a result, the thermally unstable substance sent from the LC can also be stably sent to the atmospheric pressure ion source in the state of fog. For this reason too, the fog cannot be overheated.

Further, in order to reduce chemical noise due to cluster ions and prevent thermal decomposition of sample molecules, precise temperature control of the heating part has been attempted, but it is necessary to perform an operation to find the best point for each object to be measured. This will significantly increase the annoyance. Various methods are used in liquid chromatography, and the solvent used is, for example, 100% water.
To 100% of organic solvent. Further, it is frequently practiced to add a salt or an acid to a solvent and to use a buffer solution as a mobile phase. In such a case, it is difficult to control the temperature of the vaporizer for each mobile phase and for each composition of the mobile phase, which significantly limits the application of LC / MS.

By the way, in order to make the mist uniform, the direction of the spray flow may be mechanically changed to mix the high temperature ambient flow and the relatively low temperature central flow to promote vaporization of the droplets. Further, by mechanically changing the direction of the spray flow, the central flow and the peripheral flow are exchanged, and the infrared rays emitted from the wall surface of the vaporization space can reach the inside of the spray flow. This point will be described later in detail.

Next, details of the vaporizer 8 will be described.

In FIG. 1, a spiral insertion rod 82 serving as a fluid guide is inserted into a cylindrical vaporization space 9 formed in the center of the vaporizer 8. As a result, the vaporization space 9 is formed in a spiral shape. First, the fog sprayed from the sprayer 6 (effluent from the chromatograph) enters the heated spiral vaporization space 9. The fog constantly redirects its flow along an insertion rod on the spiral. The flow of fog no longer becomes laminar, and the flow forming the fog constantly approaches the heated wall surface and is heated. Further, since the mist is constantly stirred and mixed, the mist droplets are miniaturized. Thus, since the heating is sufficiently performed, the set temperature of the vaporizer 8 can be lowered. This can prevent thermal decomposition of the heat-labile substance.

By using the vaporizing space 9 on the spiral, a uniform and finer mist can be produced. By thus introducing the fine ionization mist from the first pores 14 and the second pores 16 into the mass spectrometric section, the ions are accelerated and collided in the intermediate pressure chamber to efficiently desolvate the additional molecules. Often done. Further, since it is possible to prevent a droplet having a large diameter from being introduced into the mass spectrometric section, it is possible to significantly reduce chemical noise. As a result, a mass spectrum can be obtained as shown in FIG. As can be easily understood from this figure, cluster ions derived from a mobile phase such as water (P1 to P6 in FIG. 4) and chemical noise disappear. On the other hand, as for molecular ions, desolvation of cluster ions proceeds, so that the ion current value can be increased by stripping off the additional molecules. That is, the ion current values from the peaks Pm1 to Pm3 in FIG. 4 can be collected in the peak Pm1. As a result, molecular ions can be identified with high sensitivity.

The heating space 9 can be formed by processing the stainless steel heat block 8 with a drill or the like. A stainless steel spiral insertion rod may be inserted into this. The spiral may be single, double or more. Instead of the spiral bar, a round bar slightly smaller than the inner circumference of the vaporization space 9 and having a thread may be used as the insertion bar. The insert rod is preferably made of a thermally conductive material to prevent the fog from condensing. Furthermore, if a small heater is built in this insertion rod, the fog can be heated from the inside, and the atomization of the fog is accelerated. Further, if it is possible to take it out and clean it freely, it is possible to prevent contamination and the like. [Embodiment 2] Next, an LC / M according to another embodiment of the present invention
S will be described.

6 (a) and 6 (b) are explanatory views of the vaporizer 8 portion of the LC / MS according to this embodiment. Since the other parts are the same as those in the second embodiment, the description thereof will be omitted. Also, in the following, the description of the same parts in the other embodiments will be omitted. In this embodiment, the sample solution sprayer and vaporizer 8 is used.
The introduction into the MS part 18 after ionization in the atmospheric pressure chemical ion source 11 is the same as in the above-mentioned embodiment.
FIG. 6A is a sectional view of the vaporizer 8. In Example 1, a spiral insertion rod was inserted into the entire vaporization space 9 to guide the spray flow. In this embodiment, as shown in FIG. 6B, a fluid guide placed in a part of the vaporization space 9 is shown. In this figure, a fluid guide 83 is placed in the vaporization space 9 formed at the center of the vaporizer 8. The fluid guide 83 is made up of a plurality of propeller-shaped fins 85 twisted with each other, a cylinder 84 for fixing them, and the like. The fog sprayed from the spray 6 is the fin 8
5 creates a spiral flow in the vaporization space 9. As a result, uniform heating and finer mist are performed. It is also possible to place two or more fluid guides 83 in the vaporization space 9. [Embodiment 3] Next, an LC / M according to another embodiment of the present invention
S will be described.

FIGS. 7A and 7B are explanatory views of the vaporizer 8 portion of the LC / MS according to this embodiment. Figure 7 (a)
FIG. 4 is a sectional view of the vaporizer 8. In this embodiment, the sample solution is sprayed and introduced into the vaporizer 8, and the atmospheric pressure chemical ion source 11 is used.
The introduction into the MS portion 18 after the ionization in is the same as in the above-mentioned embodiment. As shown in FIG. 7B, the mixer 86 is placed in the vaporization space 9. The mixer 86 has a hole for the mixing portion 88 at the center thereof. A plurality of introduction holes 87 lead from the outer periphery of the mixer to the holes of the mixing section 88. The mist sprayed from the spray 6 enters the vaporization space 9 and is heated. The outer peripheral portion of the well-heated mist immediately reaches the mixing portion 88 through the introduction hole 87 formed in the outer periphery of the mixer 86. The central flow of the mist moves along the wall surface of the mixer 86 and reaches the mixing portion 88 through the introduction hole 87. In this way, the central flow can slowly move through the vicinity of the inner peripheral portion of the vaporizer 8 to be heated. Further, the mixing in the mixer 88 promotes uniform heating and finer mist. The structure of the mixer 86 can be freely made in addition to this drawing. Other shapes may be used if the peripheral flow and the central flow are separately taken and mixed at one place.

If the mixer 86 can be inserted into and removed from the vaporization space 9 from the outside, cleaning can be easily performed. [Embodiment 4] Next, an LC / M according to another embodiment of the present invention.
S will be described.

FIG. 8 is an explanatory view of the vaporizer 8 portion of the LC / MS according to this embodiment. In this embodiment, spraying of the sample solution and introduction of the vaporizer 8 and introduction of the sample solution into the MS portion 18 after ionization in the atmospheric pressure chemical ion source 11 are the same as those in the above-mentioned embodiment. FIG. 8 is a sectional view of the vaporizer 8. In this embodiment, a vaporization space 9 having a curved flow path is formed inside the vaporizer 8. The mist sprayed from the sprayer 6 enters the heated vaporization space 9. The fog changes its flow direction along the curved vaporization space 9. The fog receives a force in a direction different from the traveling direction, and the peripheral flow and the central flow forming the fog are exchanged with each other to approach the heated wall surface and are heated. As a result, the mist can be heated uniformly, and the atomization of the mist can be achieved.

In FIG. 8, the vaporization space is drawn at 90 °, but other angles may be used. A vaporization space 9 orthogonal to the vaporizer 8 may be formed and used as shown in FIG. Also, a plurality of curved vaporization spaces may be combined. The curved vaporization space 9 can also be formed by bending a metallic tube as shown in FIG. 10, inserting it into a hole formed in the block of the vaporizer 8, and then welding it with a silver rod 92 or the like.

Further, as shown in FIG. 11, two holes having different axes may be formed in the carburetor 8 to connect them in the carburetor block. It is also possible to assemble two or more vaporizer blocks with holes so that the axes of the holes are offset. [Embodiment 5] FIG. 12 shows an LC / M according to an embodiment of the present invention.
It is explanatory drawing which shows S (including interface). FIG.
Indicates a turbulent flow generation plate. In this embodiment, atomization of the sample solution, introduction of the vaporizer 8 and introduction of the sample solution into the MS section 18 after ionization in the atmospheric pressure chemical ion source 11 are the same as those in the above-mentioned embodiments.

First, the basic function of the turbulent flow generation plate will be described. As shown in FIG. 14, placing an object 46 in a fluid creates a negative pressure after the object 46. In order to compensate for this, the fluid creates a swirling vortex 33. Vortices 33 are created one after another on both sides behind the object 46. This is known as the "Karman vortex". By utilizing this vortex, the fog can be mixed and atomized.

That is, the turbulent flow generation plate 40 is placed in the vaporization space 9 as shown in FIGS. This turbulent flow generation plate 40 has a structure as shown in FIG. A plurality of small through holes are provided on the circumference of the heating space 9 from the center point 42. The turbulent flow generation plate 40 may be made of a disc such as stainless steel having a thickness of 1 to 5 mm. When the turbulent flow generation plate 40 is installed, for example, after the mist is obstructed by the turbulent flow generation plate 40 installed in the heating space 9 as shown in FIG.
A turbulent flow 33 is formed in the downstream direction through the plurality of through holes. The flow rate of the solution supplied to the sprayer 6 is, for example, about 1 ml / min, and when vaporized, it is, for example, 1000 ml / min. A gas (fog) with such a large flow rate, for example, an inner diameter of several meters
Since it passes through the vaporization space 9 having a length of m and a length of about 50 mm, the fine droplets ride on the vaporized solvent flow and pass through the through holes 41 without colliding with the turbulent flow generation plate 40. The flow passing through the through hole 41 creates a turbulent flow (vortex) 33 downstream of the turbulent flow generation plate 40. The turbulent flow 33 mechanically agitates the peripheral flow 31 in which fine droplets having a high temperature are gathered and the central flow 30 in which large droplets having a lower temperature are gathered. As a result, the temperature of the spray flow can be made uniform, and vaporization of large droplets can be promoted. Further, the complicated gas flow mechanically tears large droplets, and promotes miniaturization. In this way, the mist is suddenly made finer and uniform by passing through the turbulent flow generation plate 40. Furthermore, the atomized mist that has passed through the vaporizer 8 enters the atmospheric pressure ion source unit 11 and is ionized.

The heating space 9 can be easily made by forming a round hole having a diameter of 5 mm and a length of 50 mm in the heat block 8 made of stainless steel. The turbulent flow generation plate 40 has a heating space 9
It should be installed about 40mm from the entrance of the. In order to prevent contamination, the turbulent flow generation plate 40 is made of a material having good thermal conductivity so that it can be maintained at substantially the same temperature as the vaporizer 8. Further, the turbulent flow generation plate 40 may be fixed to the carburetor 8 with a fixing screw 43 as shown in FIG. 15 so that it can be removed and washed when the measurement is repeatedly soiled. [Embodiment 6] Next, an LC / M according to another embodiment of the present invention will be described.
S will be described.

FIG. 16 shows an LC / cell according to another embodiment of the present invention.
It is explanatory drawing of the vaporizer 8 part of MS. In this embodiment, spraying of the sample solution, introduction of the vaporizer 8 and introduction of the sample solution into the ionization MS section of the atmospheric pressure chemical ion source 11 are the same as those in the above-mentioned embodiments.

In this embodiment, holes are drilled in the vaporizer 8 at the downstream portion of the vaporization space 9 and the screws 48 are inserted. The screw 48 has a sufficient length so that it can reach the wall surface below the vaporization space 9. Further, the diameter of the screw 43 is smaller than the diameter of the vaporization space 9, and even if the screw 43 is completely tightened, a sufficient gap can be formed in the vaporization space 9. The mist enters the vaporizing space 9 and is heated by infrared rays from the wall surface of the vaporizer 8. The mist bypasses the screw 48 and creates a turbulent flow (vortex) downstream of the screw 48. The principle of turbulent flow formation is shown in FIG. As a result, the fog can be made fine and uniform as in the fifth embodiment.
The screw 48 is made of a material having good thermal conductivity to prevent condensation of the solvent and sample. Further, the screw 48 can be easily positioned from the outside by a screwdriver or the like, and the flow of mist can be freely controlled. As a result, it is possible to easily find the point where the atomization of the fog is most advanced. If the screw 48 becomes dirty, it can be easily removed and cleaned. [Embodiment 7] Next, an LC / M according to another embodiment of the present invention will be described.
S will be described.

FIG. 17 shows an LC / cell according to another embodiment of the present invention.
It is explanatory drawing of the vaporizer 8 part of MS. In this embodiment, atomization of the sample solution, introduction of the vaporizer 8 and introduction of the sample solution into the ionization MS section of the atmospheric pressure chemical ion source 11 are the same as in the first embodiment.

In this embodiment, a plurality of protrusions 45 are provided on the wall surface of the cylindrical vaporization space 9 formed in the central portion of the vaporizer 8. The mist that has bypassed the projection 45 generates a large number of turbulent flows (vortices) after the projection 45. This turbulent flow can make the fog finer and more uniform. Instead of directly forming the protrusion 45 on the wall surface of the cylindrical vaporization space 9, another cylindrical pipe 44 that can be inserted into the vaporization space 9 may be prepared and the protrusion 45 may be formed in the cylindrical pipe 44. If the cylindrical tube 44 becomes dirty, it can be removed and washed. As described above, according to the first to seventh embodiments,
The atomization of the mist is performed in the vaporization space to prevent the mist with irregularly-sized droplets from being randomly introduced into the atmospheric pressure ion source, and the finely divided droplets are ionized. Then, the solvent can be sent to the MS section for efficient solvent removal.
This minimizes chemical noise and can achieve high sensitivity analysis. It also allows the introduction of solvents of wide composition. [Embodiment 8] Next, an LC / MS according to another embodiment will be described.

In order to make the mist uniform, it is sufficient to mechanically divide the spray flow so that the spray flow is thin and the infrared rays emitted from the wall surface of the vaporizing space reach the inside of the spray flow. As shown in FIG. 18, a plurality of vaporization spaces 9 such as a plurality of thin tubes 182 are provided within the range of mist spreading from the center of the vaporizer 8. The mist is divided and separately passes through the heated plurality of thin tubes 182. Naturally, the diameter of the fog is limited to the diameter of the thin tube 182 or less. Since the surface area of the capillaries is increased, the infrared rays emitted from the wall surface of the capillaries 182 are increased accordingly, and are easily heated to the center of each mist. This promotes the miniaturization of fog. Further, when the diameter of the flow velocity of the mist is large, the heat does not reach the center portion easily, and the temperature of the vaporizer 8 must be set high in order to heat the center portion of the mist, but in the case of the present embodiment, Since the heating is sufficiently performed, the set temperature of the vaporizer 8 can be lowered. This can prevent thermal decomposition of the heat-labile substance. The mist that has passed through the plurality of thin tubes 182 enters the atmospheric pressure ion source unit 11, where the solvent molecules are first ionized by the corona discharge generated from the tip of the corona discharge needle electrode to which a high voltage of 3 to 5 kV is applied. It The generated ions then repeat the ion molecule reaction, and finally ionize the sample molecule. Ions are introduced into the intermediate pressure portion 15 from the first pores 14. This is the same as in the previous embodiment.

As described above, a fine mist can be created by employing a plurality of vaporization spaces 9, and this is ionized to introduce the ions into the mass spectrometric section 18 through the first pores 14 and the second pores 16. You can As a result, the fine droplets are subjected to accelerated collision of ions in the intermediate pressure chamber, and the additional molecules are efficiently desolvated. Further, since it is possible to prevent a droplet or cluster ion having a large diameter from being introduced into the mass spectrometric section, chemical noise can be significantly reduced. Further, cluster ions and chemical noise derived from a mobile phase such as water can be suppressed low. On the other hand, molecular ions can increase their ionic current value by stripping off additional molecules. As a result, molecular ions can be identified with high sensitivity.
The heating space 9 can be formed by processing the heat block 8 made of stainless steel with a drill or the like. [Embodiment 9] Next, an LC / M according to another embodiment of the present invention
S will be described.

FIG. 20 shows an LC / LC according to another embodiment of the present invention.
It is explanatory drawing of the vaporizer 8 part of MS. In this embodiment, the spraying of the sample solution, the introduction of the vaporizer 8 and the introduction into the MS section 18 after the ionization in the atmospheric pressure chemical ion source 11 are the same as those in the previous embodiment. FIG. 20 is a sectional view of the vaporizer 8. A hole with a diameter of 5 mm and a length of about 50 mm is bored in the center of the vaporizer 8, and a rod-shaped partition plate 183 is inserted therein. Figure 2
In the case of 0, a cross-shaped partition plate is shown, but the shape of the partition plate 83 can be freely selected. The vaporization space 9 may be separated into a plurality of vaporization spaces by inserting the partition plate so that the fog can move in each vaporization space. According to this embodiment,
Similar to the eighth embodiment, the subdivision of the mist flux and the increase of the heating wall surface are achieved. As a result, vaporization of mist droplets is promoted, and the mist is made fine. Since the partition plate 183 is made of a material having a high thermal conductivity, the mist is heated well, and the condensation of the sample can be prevented. Furthermore, if a small heater is built in the partition plate 183, the fog can be heated from the inside, and the atomization of the fog is accelerated. Further, if the partition plate 183 can be taken out to the outside, cleaning can be easily performed. [Embodiment 10] Next, an LC / LC according to another embodiment of the present invention will be described.
The MS will be described.

FIG. 21 shows an LC / LC according to another embodiment of the present invention.
It is explanatory drawing of the vaporizer 8 part of MS. In this embodiment, the spraying of the sample solution, the introduction of the vaporizer 8 and the introduction into the MS section 18 after the ionization in the atmospheric pressure chemical ion source 11 are the same as those in the previous embodiment. FIG. 21 is a sectional view of the vaporizer 8. For example, a hole having a diameter of 5 mm and a length of 50 mm is bored in the center of the carburetor 8, and an insertion rod 185 having a plurality of protrusions 184 attached to its outer circumference is inserted therein. As a result, the vaporizing space 9 is formed in the gap between the outer periphery of the insertion rod 185 and the inner periphery of the hole of the vaporizer 8. The thickness of the vaporizing space 9 can be freely selected depending on the diameter of the insertion rod. If the vaporizing space 9 is thinned to about 1 mm, the fog can be sufficiently heated. If the insertion rod 185 can be taken out to the outside, cleaning can be easily performed. Further, by enclosing a small heater 186 in the insertion rod 185 and heating the fog from the inside, the atomization of the fog is further promoted. [Embodiment 11] Next, LC / according to another embodiment of the present invention
The MS will be described.

FIG. 22 shows LC / s according to another embodiment of the present invention.
It is explanatory drawing of the vaporizer 8 part of MS. In this embodiment, the spraying of the sample solution, the introduction of the vaporizer 8 and the introduction into the MS section 18 after the ionization in the atmospheric pressure chemical ion source 11 are the same as those in the previous embodiment. FIG. 22 is a sectional view of the vaporizer 8 taken along the spray direction. At the center of the carburetor 8, for example, a diameter of 5 m
A hole having a length of m and a length of about 50 mm is bored and used as a vaporization space 9. A filling 187 such as quartz wool or stainless steel wool is placed in the vaporizing space 9. The mist that has flowed into the vaporization space 9 comes to the filling 187 such as quartz wool or stainless steel wool and becomes a plurality of streams, and the vaporizer 9
Receives heat from the wall surface. This further promotes atomization of the fog.

As described above, according to the eighth to eleventh embodiments, it is possible to prevent mist with irregular diameters of the droplets from being randomly introduced into the atmospheric pressure ion source section 11 and to make the temperature uniform to make fine particles. Then, the droplets with uniform diameter are ionized and sent to the MS section. Therefore, the solvent can be efficiently removed by the ion drift voltage V. This minimizes chemical noise and can achieve high sensitivity analysis. Further, the temperature setting of the vaporizer can be kept low, and the thermal decomposition of the thermally unstable substance can be prevented. [Embodiment 12] FIG. 23 shows an L according to another embodiment of the present invention.
It is explanatory drawing which shows C / MS (including interface).

In FIG. 23, the ion sampling shaft 13 is arranged near the spray peripheral flow 31. As a result, the fine mist is mainly ionized and the first pores 14,
It can be introduced into the mass spectrometric section 18 through the second pores 16. That is, since a large amount of fine mist is gathered around the ejected mist, it is characteristically selected and guided to the intermediate pressure chamber 15. The finer droplets repeat accelerated collision of ions by the ion drift voltage V applied between the partition walls 141 and 161 in the intermediate pressure chamber, so that the additional molecules are efficiently desolvated. Further, since it is possible to prevent a droplet having a large diameter at the center of the spray flow from being introduced into the mass spectrometric section, chemical noise can be greatly reduced. Therefore, cluster ions and chemical noise derived from the mobile phase such as water can be suppressed. On the other hand, molecular ions can increase their ionic current value by stripping off additional molecules. As a result, molecular ions can be identified with high sensitivity. [Embodiment 13] Next, an LC / LC according to another embodiment of the present invention will be described.
The MS will be described.

FIG. 24 shows the LC / s according to another embodiment of the present invention.
It is explanatory drawing of MS. In the figure, the same reference numerals as those in FIG. 23 denote the same parts, and thus the description thereof will be omitted. Only the new code will be explained.

In FIG. 24, 123 is a partition wall, 124 is a spray flow sampling hole, 25 is a first exhaust port, and 26 is a second exhaust port. In this embodiment, the process of spraying the sample solution and the introduction of the vaporizer 8 are the same as in the above embodiment. A partition wall 123 having a hole 124 is placed downstream of the vaporization space 9 and in front of the atmospheric pressure ion source 11. The vaporization space 9 and the atmospheric pressure ion source 11 are separated by the partition wall 123. The pores 124 are installed near the peripheral flow 31 which is deviated from the central axis 30 of the spray flow. Fine mist is concentrated in the peripheral part compared to the central part, which allows the mist in the peripheral part of the spray flow to be selectively introduced into the atmospheric pressure ion source part 11 for ionization. Note that the atomized flow that is not introduced into the internal atmospheric pressure ion source 11 is discharged from the first exhaust port 25 to the outside. Further, the gas introduced into the atmospheric pressure ion source unit 11 and not involved in the ionization is discharged to the outside from the second discharge port 26 of the atmospheric pressure ion source unit 11. In the case of the first embodiment, turbulent flow in the atmospheric pressure ion source section 11 may mix droplets having different diameters and may be introduced into the mass spectrometric section. However, in order to actively sample only fog the periphery of the spray stream according to the present embodiment, it is possible to selectively ionize a fine mist fully equipped particle size. The fine ions with uniform particle size are subjected to accelerated collision by the ion drift voltage V in the intermediate pressure chamber,
As a result, desolvation is efficiently performed.

Further, in the present embodiment, the partition wall 123 with the hole 124 is fixed in the apparatus, but it can be adjusted from the outside in the direction perpendicular to the spray flow. This allows the spray stream to be freely sampled and allows droplets of the desired diameter to be sampled and ionized. By adjusting from the outside, it becomes possible to find the best points such as maximum sensitivity and minimum noise.

In Examples 12 and 13, the method of sampling the ions generated under the atmospheric pressure was described by using the pores. This may be any ion as long as it can introduce the generated ions into the MS portion while maintaining the pressure difference, and can be replaced with pores by slits, capillaries or the like. The mass spectrometer is not limited to QMS. It may be a magnetic field type MS, an ion trap MS or another MS having a different principle.

As described above, the twelfth and thirteenth embodiments
According to the method, it is possible to prevent mist with irregularly-sized droplets from being randomly introduced into the atmospheric pressure ion source section, ionize droplets with uniform diameters, and send them to the MS section for efficient desolvation. be able to. This minimizes chemical noise and can achieve high sensitivity analysis. [Experiment] The following experiment was conducted to verify the effect of the present invention. (1) Apparatus LC / MS having the configuration shown in FIG. 12 was used. However, the analytical column 4 was removed, and the sample injection port 3 and the sprayer 6 were directly connected.
A comparison was made between the case where the turbulent flow generation plate 40 was attached and the case where it was removed.

As the mobile phase 1, pure water was used. Water is the most difficult to desolvate and produces large cluster ions. The vaporizer temperature was fixed at 400 ° C., the temperature of the atomizer 6 and the flow rate of water were changed, and the appearance of cluster ions was observed. Corona discharge voltage HV is 3 kV, and collision dissociation drift voltage V is 5
0V and other parameters were fixed during the experiment. The mass spectrometer 18 was swept while changing the temperature of the atomizer 6 and the flow rate of water, and mass spectra were repeatedly collected. Cluster ions on one mass spectrum are integrated and output as a total ion current value (Total Ion Current, TIC). TI
A large C indicates that many cluster ions have appeared. Here, TIC and chemical noise can be said to be synonymous. (2) Results and consideration The experimental results are shown in FIGS. 25 and 26. In FIG. 25, the atomizer 6
The results of observing the appearance of cluster ions by changing the temperature and the flow rate of water are shown below. The horizontal axis represents the sprayer temperature, and the vertical axis represents TIC. X and O indicate the TIC when the turbulent flow generation plate 40 is removed, and □ indicates the TIC when the turbulent flow generation plate 40 is attached. The flow rate of the mobile phase is x for 1 ml / min, ○ for 0.5 ml / mi
n and □ are flow rates of 1 ml / min. When the turbulent flow generation plate 40 is not attached, there are no measurement results at 200 ° C. for x and o. This is because when the temperature of the sprayer 6 was set to 250 ° C. or lower, the cluster ions of water rapidly increased and the TIC became extremely unstable, making it impossible to measure. The temperature of the atomizer 6 is set to 2
When set to 50 ° C, TIC is 2 at a flow rate of 1 ml / min.
It becomes × 10 ⁷ . When the flow rate is halved to 0.5 ml / min, T
The IC will be half, 1 × 10 ⁷ . If the temperature of the sprayer 6 is set high, TIC (chemical noise) is reduced. But,
8 x 1 even at a flow rate of 0.5 ml / min and a sprayer 6 temperature of 350 ° C.
It does not ^fall below 0 ⁶ . No further heating is possible to avoid thermal decomposition of the sample.

When the turbulent flow generation plate 40 is attached, the TIC (chemical noise) becomes 1 × 10 ⁶ or less, and when the temperature of the sprayer 6 is 300 ° C. or higher, one digit is larger than when the turbulent flow generation plate 40 is not attached. As described above, when the temperature of the sprayer 6 is 250 ° C. or lower, it is dramatically reduced to two digits. Moreover, 200 ° C to 350 ° C
There is no big change in TIC. Without the turbulent flow generation plate 40, 200 ° C. was noisy and unusable. When the turbulent flow generation plate 40 is attached, measurement becomes possible. It is extremely effective to be able to use the condition of 250 ° C. or lower because thermal decomposition of the sample can be avoided. The turbulent flow generation plate 40 is the result of achieving finer and more uniform mist.

FIG. 26 shows mass spectra with and without the turbulent flow generation plate 40. The upper part of FIG. 26 is a mass spectrum when the turbulent flow generation plate 40 is not present, and the lower part is a mass spectrum when the turbulent flow generation plate 40 is present. The conditions for acquiring both mass spectra are the same.
Mobile phase flow rate is 1 ml / min, atomizer 6 temperature is 250 ° C,
The vaporizer temperature is 400 ° C. When the turbulent flow generation plate 40 is not provided, unidentified ions appear with an intensity of 100,000 to 50,000 over the front region from m / z 100 to 1000.
If there is a turbulent flow generation plate 40, the strength from m / z 200 to 10,0
No peaks above 00 have appeared. Many cluster ions have disappeared by the turbulent flow generation plate 40.

The low noise and independence of the atomizer temperature have the following advantages. There is no need to change the atomizer temperature for mobile phases of different composition. This is extremely effective for gradient measurement. The sprayer temperature may be set to approximately 250 ° C., and the operability can be remarkably enhanced. Further, if the temperature of the sprayer is approximately 250 ° C., a thermally unstable substance can be prevented and stable measurement can be performed.

[0060]

As described above, according to the present invention,
It is possible to improve the accuracy of mass spectrometry.

[Brief description of drawings]

FIG. 1 is an overall view of LC / MS.

FIG. 2 shows a thermal spray and vaporizer.

FIG. 3 is a diagram showing details of a vaporizer.

FIG. 4 is an explanatory diagram of chemical noise in a mass spectrum.

FIG. 5 is a diagram showing a mass spectrum obtained by the present invention.

FIG. 6 is a diagram showing details of a vaporizer in Example 2.

FIG. 7 is a diagram showing details of a vaporizer in Example 3.

FIG. 8 is a diagram showing details of LC / MS in Example 4.

FIG. 9 is a diagram showing details of a vaporizer in Example 4.

FIG. 10 is a diagram showing details of a vaporizer in Example 4.

FIG. 11 is a diagram showing details of a vaporizer in Example 4.

FIG. 12 is a diagram showing details of a vaporizer in Example 5.

FIG. 13 is a diagram showing details of a turbulent flow generation plate in Example 5.

FIG. 14 is an explanatory diagram of Karman vortex generation in Example 5.

FIG. 15 is a diagram showing details of atomization in Example 6;

FIG. 16 is a diagram showing details of a vaporizer in Example 7.

FIG. 17 is a diagram showing details of a vaporizer in Example 7.

18 is an overall view of LC / MS in Example 8. FIG.

FIG. 19 is a diagram showing details of a vaporizer in Example 8.

FIG. 20 is a diagram showing details of the vaporizer in Example 9.

FIG. 21 is a diagram showing details of a vaporizer in Example 10.

FIG. 22 is a diagram showing details of the vaporizer in Example 11.

23 is an overall view of LC / MS in Example 12. FIG.

FIG. 24 is an overall view of LC / MS in Example 13.

FIG. 25 is a diagram showing a relationship between TIC and atomizer temperature.

FIG. 26 is a mass spectrum.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mobile phase, 4 ... Analytical column, 6 ... Atomizer, 8 ... Vaporizer, 10 ... Corona discharge needle electrode, 11 ... Atmospheric pressure chemical ion source part, 14 ... First pore, 16 ... Second pore, 17 ... Vacuum pump, 18 ... Mass spectrometric section, 82 ... Spiral insertion rod.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 27/62-27/70 G01N 30/72 H01J 49/00-49/48

Claims (2)

(57) [Claims] 1. A heating unit which is equipped with a spraying unit for spraying the effluent from a liquid chromatograph, a communication passage for passing a spray flow from the spraying unit, and an exhaust passage communicating with the communication passage for heating. Liquid chromatograph coupling having an ionization part for ionizing the spray flow from the heating part by corona discharge of a needle electrode and a mass spectrometric part for mass spectrometrically guiding ions generated in the ionization part through pores A mass spectrometer, wherein a partition having a through hole is provided between the heating unit and the ionization unit, and the through hole is formed at a position displaced from a central axis of the communication passage. Liquid chromatograph coupled mass spectrometer. 2. The liquid chromatograph coupled mass spectrometer according to claim 1 , wherein the partition wall can be adjusted from the outside in a direction perpendicular to the central axis of the communication passage.