CN113421815A

CN113421815A - Vacuum electrospray ion source assembly and electrospray method

Info

Publication number: CN113421815A
Application number: CN202110680186.XA
Authority: CN
Inventors: 朱建雄; 朱光皓; 刘倩; 王暐翔
Original assignee: Guangdong Lianjie Biotechnology Co ltd
Current assignee: Guangdong Lianjie Biotechnology Co ltd
Priority date: 2021-06-18
Filing date: 2021-06-18
Publication date: 2021-09-21
Anticipated expiration: 2041-06-18
Also published as: CN113421815B

Abstract

The invention belongs to the technical field of analytical instruments, and provides a mass spectrum ion source assembly and an electrospray method, wherein the assembly comprises a sample injection spray needle and a vacuum atomization cavity, the sample injection spray needle penetrates through the vacuum atomization cavity and can move up and down relative to the vacuum atomization cavity, an upper needle inlet passage is arranged at the upper part of the vacuum atomization cavity, a lower sealing sampling passage is arranged at the lower part of the vacuum atomization cavity, the sample injection spray needle comprises a needle arm and a needle point with a groove, and the upper needle inlet passage is sleeved at the outer side of the needle arm and is in air-tight joint with the needle arm. The mass spectrum ion source component can perform micro sampling and micro spraying, atomized ions enter a mass spectrometer for separation and detection, and are not ionized and are pumped away by a preceding stage vacuum chamber, and on the other hand, the atomization effect can be extremely achieved by micro ionization spraying in a vacuum state, so that the sensitivity can be improved, and the matrix effect can be inhibited.

Description

Vacuum electrospray ion source assembly and electrospray method

Technical Field

The invention belongs to the technical field of analytical instruments, and particularly relates to a mass spectrum ion source component for carrying out electrospray on a sample under a vacuum condition and a method for carrying out electrospray on the sample by utilizing the mass spectrum ion source component.

Background

The sensitivity of mass spectrometry detection is affected in many ways, with the ion source being the most affected. Three main factors need to be considered in the design of a liquid mass spectrometry ion source based on sample atomization: ionization efficiency (atomization efficiency), resistance to matrix effects, and collection efficiency. If the atomization efficiency is pushed to be extremely high, so that the liquid sample forms extremely fine droplets, such as micron or even micron below scale level droplets, the efficiency of Electrospray (ESI) or chemical ionization of aerosol discharge (APCI) can be greatly improved, and meanwhile, the extremely fine droplets mean that the inhibition effect of viscous matrixes in the sample on atomization is inhibited, and the matrix effect is weakened or even eliminated.

In the case of electrospray, the atomization efficiency can be improved by increasing the spray voltage, increasing the flow rate of the spray gas, heating, reducing the air pressure in the spray environment, reducing the flow rate of the spray liquid, and the like, wherein the reduction of the liquid flow rate is proved to be an extremely effective way by Nanospray (Nanospray), the Nanospray ion source can obtain extremely high ionization efficiency without auxiliary gas or heating, the detection sensitivity is extremely high, only the operation difficulty is high, the stable collection efficiency cannot be ensured, and the Nanospray ion source can only be used for qualitative analysis, but cannot be used for quantitative analysis.

Chinese patent publication No. CN107039232A discloses a device for spraying under vacuum condition, which can improve the ion collection efficiency, thereby improving the sensitivity of mass spectrometry detection. In the patent application, a capillary tube is used for conveying a sample, a liquid sample is introduced into a vacuum environment from a sample bottle for electrospray under the drive of pressure difference caused by the spray, and the sample introduction mode is suitable for single sample analysis, otherwise, the sample is switched, and the sample introduction capillary tube needs to be replaced or cleaned, so that inconvenience is caused. Moreover, the liquid in the spray nozzle of the capillary tube is frozen and blocked because the sample rapidly expands in volume to cause sudden temperature drop when the sample is atomized. In order to solve the problem, the patent application provides a method for intermittently inputting gas, so that instantaneous normal pressure is generated in the spraying cavity, the spraying is performed as if the spraying is performed under the normal pressure condition, and the icing of the capillary nozzle is avoided. However, this approach offsets the assisting effect of vacuum conditions on atomization, and does not benefit the improvement of ionization efficiency, and therefore, this solution can only improve ion collection efficiency.

The current widely used spray ion sources in the market are all spraying under normal pressure, especially the ion sources connected with liquid chromatogram, because the flow rate of chromatogram mobile phase is basically in the range of hundreds of microlitres to a few milliliters, the vacuum condition spraying can not be realized at all, therefore, the aim of improving the ionization efficiency can be achieved only by depending on high voltage and large flow auxiliary spray gas and heating. There is therefore a need for improvements in existing ion sources.

Disclosure of Invention

The invention mainly aims to provide a mass spectrometry ion source for electrospray under a vacuum condition, aiming at improving the atomization efficiency (namely ionization efficiency) and ion collection efficiency of electrospray, thereby improving the sensitivity of mass spectrometry detection.

The technical problem of the invention is solved by the following technical scheme:

a vacuum electrospray ion source assembly comprising: sampling spray needle and vacuum atomization chamber, sampling spray needle runs through vacuum atomization chamber and can for vacuum atomization chamber reciprocates, and vacuum atomization chamber upper portion is provided with upper portion needle inlet passageway, and the lower part is provided with the lower part and seals the sample access, wherein sampling spray needle includes needle arm and trough of belt needle point, and the needle arm outside and with needle arm gas tightness joint are located to upper portion needle inlet passageway cover, and the lower part seals the sample access and is used for sealing vacuum atomization chamber lower part, allows the trough of belt needle point of sampling needle to see through simultaneously the sample of below is stretched into to the bottom of sample access dips in and gets the sample.

Further, the needle arm of the sample injection spray needle and the needle point with the groove are integrally formed or detachably connected.

Further, the needle arm and the grooved needle tip are interconnected by a handling end.

Further, the lower sealed sampling passage includes a vacuum valve, and further includes a self-healing gasket and/or a conduit forming a gas-tight joint with the needle arm.

Further, the lower sealed sampling passage further comprises a needle tip displacement device.

Further, the lower sealed sampling passage further comprises a sealing sleeve for sealing with a container of a sample to be measured.

Further, a high voltage contact is arranged on the needle arm.

Further, the vacuum electrospray ion source assembly further comprises an ion collection channel.

The embodiment of the invention also provides mass spectrum equipment comprising the vacuum electrospray ion source component.

The embodiment of the invention also provides a vacuum electrospray method, which comprises the following steps:

s1, the sample injection spray needle penetrates through the vacuum atomization cavity to move downwards, a groove needle point is arranged at the bottom of the sample injection spray needle, and the groove needle point enters a sample to be detected to enable a groove on the groove needle point to be completely immersed in the sample to be detected.

And S2, the sample injection spray needle moves upwards, and when the needle point of the groove is located at a position (spray position) which is 5-25 mm higher than the ion collection passage on the upper side of the center of the vacuum atomization cavity, high-voltage electricity is conducted to the sample injection spray needle for electro-spray.

Preferably, the method is implemented by a vacuum electrospray ion source assembly provided by an embodiment of the present invention.

Further, the sampling amount of the sample to be tested in the step S1 is 0.1-10 μ L.

Further, the vacuum atomization cavity is in sealing joint with the needle arm of the sample injection spray needle through the upper needle inlet passage and the lower sealing sampling passage maintains vacuum degree in the whole process of the method.

Further, the method may further comprise the step of replacing the grooved needle tip.

Further, in step S2, when the sample injection spray needle moves upward, the time is 0-2 seconds after the grooved needle tip completely leaves the lower sealed sampling passage, so that the gas leaking into the vacuum atomization chamber is pumped away by the mass spectrometry foreline vacuum chamber, that is, the vacuum balance is achieved. Compared with the prior art, the invention has the advantages that:

the invention has the main advantages that:

1) micro sampling and micro spraying, wherein ions generated in the atomized cloud are collected and enter a mass spectrum for separation and detection, and are pumped away by a preceding stage vacuum chamber without ionization, so that the ions cannot be deposited in a mass spectrometer, and the vacuum in the mass spectrometer cannot be damaged and cannot pollute the inside of the mass spectrometer;

2) the atomization effect can be extremely achieved by trace ionization spraying in a vacuum state, so that the sensitivity can be improved, and the matrix effect can be inhibited;

3) in the design, the aperture of the ion collection channel can be enlarged to the extent that the vacuum atomization cavity and the mass spectrum foreline vacuum chamber (namely, the mass spectrum Q0) are completely fused, so that the ion collection efficiency can reach 100 percent, and the sensitivity can be further improved;

4) the sample introduction mode avoids the problems that the sample is splashed when vacuum is introduced from normal pressure, the vacuum spray blocks a conveying pipeline due to the refrigeration effect and the like, and is convenient for cleaning or replacing the sample introduction needle, so that the sample introduction is quick and is convenient for automation.

Compared with the traditional ESI ion source, the invention realizes the mass spectrometry of trace, high flux and high ionization efficiency:

1) various problems of a liquid chromatography-mass spectrometry combined system are avoided, the liquid mass spectrometry analysis system and the operation difficulty are greatly simplified, the analysis speed is greatly improved, and the flux of an instrument can be improved by 10-30 times;

2) the sample amount is small, the treatment is easy, and the ionization efficiency is improved, namely the sensitivity is improved;

3) and a large amount of organic solvent is saved, so that the analysis cost can be reduced, and the pollution can be reduced.

4) The ion collecting pipe can be greatly enlarged, so that the collecting efficiency can reach 100%, and the problem that the traditional collecting capillary is frequently blocked due to small inner diameter can be avoided.

The invention provides a device for carrying out electrospray by micro sample introduction and then switching on high voltage in a vacuum state, which is a spraying cavityThe body is directly connected with the liquid phase mass spectrum foreline vacuum chamber and keeps consistent with the foreline vacuum chamber, and the mass can reach 10 DEG^-4Pa to 10^-5Pa, the two can even be integrated, thus not only improving the atomization efficiency of the spray, but also leading the collection to be 100 percent all the time, stable and extremely; furthermore, matrix effects can be suppressed or eliminated because maximization of atomization efficiency makes it difficult for the matrix that interferes with atomization to function.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention.

Fig. 1 is a schematic diagram illustrating a spray state of an ion source assembly according to an embodiment of the present disclosure;

fig. 2 is a schematic view illustrating a sample introduction state of an ion source assembly according to an embodiment of the present application;

fig. 3 is a schematic diagram illustrating a spray state of an ion source assembly provided in a second embodiment of the present application;

fig. 4 is a schematic view illustrating a sealed sampling state of an ion source module according to a second embodiment of the present application;

fig. 5 is a schematic diagram illustrating an in-and-out state of a sample injection spray needle of an ion source assembly provided in a third embodiment of the present application;

fig. 6 is a schematic view of a sample introduction state of an ion source assembly provided in the third embodiment of the present application;

fig. 7 is a schematic diagram illustrating a spray state of an ion source module according to a third embodiment of the present disclosure.

The labels in the figure are: the device comprises a sample injection spray needle 1, a high-voltage contact 11, a needle arm 12, a grooved needle tip 13, a vacuum atomization cavity 2, an upper needle insertion passage 3, a self-healing sealing gasket 41, a vacuum valve 42, a needle grasping claw 43, a sample bottle sealing sleeve 44, a sampling guide tube 45, a needle grasping device 46, an ion collection passage 5, a mass spectrum pre-stage vacuum chamber 6, a sample 7 and a high-voltage connecting device 8.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

An embodiment of the present invention provides a vacuum electrospray ion source assembly, as shown in fig. 1, comprising: the sample injection spray device comprises a sample injection spray needle 1, a vacuum atomization cavity 2, an upper needle inlet passage 3, a lower sealed sampling passage (including a self-healing sealing gasket 41, a vacuum valve 42 and a needle grasping claw 43 in the figure 1), and an ion collection passage 5, wherein the sample injection spray needle 1 is used for dipping and carrying a sample 7 so as to convey the sample 7 to the vacuum atomization cavity 2, and then electric atomization is realized.

Specifically, the upper end of the sample injection spray needle 1 is a needle arm connected high-pressure device, the lower end of the sample injection spray needle is a needle point 13 with a groove for sampling, and the sample injection spray needle ascends to enter the vacuum atomization cavity after sampling; the lower sealed sampling passage is used for enabling the sample injection spray needle to penetrate through the lower portion of the vacuum atomization cavity and then extend into a sample to dip the sample, and the valve switch of the lower sealed sampling passage is utilized to maintain the vacuum state of the vacuum atomizer cavity.

The upper needle inlet passage 3 is communicated with the top of the vacuum atomization cavity 2, and a needle arm 12 of the sample injection spray needle 1 and the needle inlet passage 3 form a sealed state; one end of the ion collecting channel 5 is in butt joint with the vacuum atomizing cavity 2, and the other end of the ion collecting channel is connected with the mass spectrum fore-stage vacuum chamber 6 to form airtight insulation butt joint.

The inner diameter of the ion collection channel ranges from 0.3mm to 30mm, and preferably, the inner diameter of the ion collection channel can be expanded to the extent that the vacuum atomization cavity and the mass spectrum forevacuum chamber 6 (also called mass spectrum Q0) are completely fused.

In some embodiments, the vacuum electrospray ion source assembly described above can be integrated into a mass spectrometry apparatus.

Specifically, the vacuum atomization cavity 2 is kept sealed in the process that the sample injection spray needle 1 moves up and down. The upper portion needle inserting passage 3 and the lower portion sealed sampling passage 4 are respectively connected to the upper end and the lower end of the vacuum atomization cavity 2 in a sealing mode, the central lines of the upper portion needle inserting passage and the lower portion sealed sampling passage are on the same straight line, the sample injection spray needle 1 can be sleeved in the upper portion needle inserting passage 3 and penetrates through the vacuum atomization cavity 2 and the lower portion sealed sampling passage 4, meanwhile, the portion, clamped by the upper portion needle inserting passage 3 and the lower portion sealed sampling passage 4, of the sample injection spray needle 1 forms sealed matching, and the vacuum degree of the vacuum atomization cavity 2 is guaranteed. The sample injection spray needle 1 can move up and down along the upper needle insertion passage 3 and is used for sampling when moving downwards, the sample injection spray needle moves upwards after sampling, the sample is conveyed to the vacuum atomization cavity 2 for atomization treatment, and meanwhile, the lower sealed sampling passage 4 seals the vacuum atomization cavity 2 to maintain the vacuum degree.

In one embodiment, the vacuum electrospray ion source assembly further comprises a mass spectrometry forevacuum chamber 6 for evacuating the vacuum nebulization chamber 2.

The ion collection passage 5 is arranged at one end (shown as the right end in figure 1) of the horizontal center of the vacuum atomization cavity 2, so that when the sample injection spray needle 1 carries a sample to the position, 5-25 mm higher than the ion collection passage, of the vacuum atomization cavity 2 for atomization, all generated ions can be collected, meanwhile, the vacuum atomization cavity 2 and the mass spectrum pre-stage vacuum chamber 6 (shown with a body structure in figure) are in airtight insulation butt joint with the ion collection passage 5, and all ions are guaranteed to enter a mass spectrometer for detection.

The vacuum electrospray ion source component realizes the micro-sampling of a sample and the mass spectrometry of the sample with high flux and high ionization efficiency by the mutual matching of the components in a vacuum state.

Specifically, the sample injection spray needle 1 comprises a grooved needle tip 13 and a needle arm 12, and the grooved needle tip 13 and the needle arm 12 are integrally formed and can also be of a detachable structure. For the detachable embodiment, the grooved needle tip 13 is connected to the needle arm 12 via a loading and unloading tip, wherein the loading and unloading tip may be flat, round with a groove, flat or "T" shaped. The length range of the needle tip 13 with the groove is 5-50 mm, and the diameter range is 0.3-1.2 mm. In the embodiment of the invention, the electrospray state of the sample is controlled mainly by taking the running position of the sample injection spray needle 1 as a main part.

Preferably, the grooved tip 13 is engraved with one or more grooves for carrying a sample. Further preferably, the groove end coincides with the end of the grooved needle tip 13.

Specifically, the upper end of the needle arm 12 is connected to a sample injector arm (not shown) in an insulating manner, and if the needle arm is used for manual sample injection, the needle injector arm is connected to a handle made of an insulating material, a needle grasping device is arranged at the lower end of the sample injector arm, the needle grasping device is a hollow tube with a downward opening, preferably, the length range of the hollow tube is 3-10 mm, the inner diameter of the hollow tube is consistent with the outer diameter of the loading and unloading end, 2 to at most 3-10 mm gaps are formed in the side surface of the hollow tube, the tube wall of the hollow tube is divided into 2 to a plurality of claw sheets bent centripetally, the claw sheets have strong elasticity, the downward opening is in a shape of an inverted cone, the loading and unloading end can be smoothly inserted into and firmly grasped by the claw sheets, and the grooved needle point can be smoothly pulled out by slight external force. The needle arm 12 can be made of any rigid hard material, such as stainless steel, various alloys, ceramics, PTFE (polytetrafluoroethylene), carbon fiber rods, glass fiber rods and the like, the length range is preferably 50-150 mm, the needle arm is enough to drive the grooved needle tip 13 to move up and down by 30-120 mm, and the grooved needle tip 13 is just at the best spraying position when the sample injection spraying needle 1 rises to the highest point.

Referring to fig. 1, the needle inserting passage 3 in the upper portion is provided with a hollow channel for sleeving the sample injection spray needle 1, the lower portion sealing sampling passage comprises a self-healing sealing sheet 41, a vacuum valve 42 and a needle grasping claw 43 (needle tip replacement device), the sample injection spray needle 1 penetrates the needle grasping claw 43 and the self-healing sealing sheet 41, the self-healing sealing sheet 41 automatically forms a seal after the sample injection spray needle 1 goes upward, and then the vacuum valve 42 is closed, so that the vacuum state of the vacuum atomization cavity 2 is continuously maintained, and the atomization efficiency is ensured not to be influenced by air leakage.

The term "self-healing" in embodiments of the present invention refers to an automatic recovery to an airtight state after no further insertion of the needle tip or arm therein.

Furthermore, a high voltage contact 11 is arranged on the upper part of the needle arm 12 of the sample injection spray needle 1, and is used for conducting high voltage electricity to the sample injection spray needle 1. Preferably, the high voltage contact 11 is a metal ring fitted over the upper end of the metal needle arm 12. Correspondingly, the vacuum electrospray ion source assembly further comprises a high voltage connection device 8, the high voltage connection device 8 is preferably a metal elastic sheet which is arranged above the outside of the vacuum atomization cavity 2 and is connected to high voltage, when the sample injection spray needle 1 rises to the highest motion point, the grooved needle tip 13 just reaches the optimal position of electrospray, the metal elastic sheet is contacted with a metal ring on the needle arm 12, the grooved needle tip 13 is connected with high voltage to generate electrospray, once the needle arm 12 moves downwards, the high voltage is immediately disconnected, and the arrangement can realize perfect matching of the high voltage and the spray without other structures.

Specifically, the ion collecting passage 5 is a hollow pipe with an inner diameter ranging from 0.3mm to 30mm, and forms an airtight insulation butt joint with the vacuum atomization cavity 2. Meanwhile, the ion collection passage 5 is also in airtight insulation butt joint with the mass spectrum forevacuum chamber 6. The ion collecting passage 5 is preferably made of a metal tube or a non-metal tube with conductive sleeves or conductive coatings at two ends, such as a glass tube, a ceramic tube, a PEEK (polyether ether ketone) tube, a polytetrafluoroethylene tube and the like, and the ion collecting passage and the grooved needle tip 13 form an electrospray counter electrode by itself carrying a voltage of-120V to + 120V. The ion collection passage 5 may be heated to 50 c to 350 c, which may be infrared heating, so that solvent molecules in the solvated ions are evaporated and removed.

Specifically, the vacuum atomization cavity 2 is a closed vacuum cavity with three connecting passages, and the inside of the cavity can completely contain the atomization cloud volume. In the embodiment of the invention, when the methanol solution with the spraying amount of 0.1-10 mu L is adopted for spraying, a water drop-shaped atomized cloud with the length of about 20mm and the maximum diameter of about 10mm is obtained. Therefore, the interior of the chamber is limited only to allow sufficient atomization of the sample solution 7 and the beads do not contact the walls of the chamber before they are drawn into the mass spectrometry foreline vacuum chamber 6, and the shape of the interior cavity is not limited. The vacuum atomizing chamber 2 can be made of metal or hard non-metal materials.

Specifically, the height of the upper needle passage 3 is set such that when the sample injection spray needle 1 is lifted to the highest position, a part of the needle arm 12 is still contained in the passage, and the upper needle passage 3 is blocked to prevent vacuum leakage. The needle arm 12 of the sample injection spray needle 1 forms a sealing fit with the hollow part of the needle inlet passage 31, and the needle arm 12 does not cause vacuum leakage when moving up and down in the passage. In one embodiment, the needle arm 12 is a bare metal cylinder, and any contact part between the upper needle insertion path 3 and the lower sealed sampling path and the sample injection and spray needle 1 is insulated, so as to avoid that the whole needle insertion path or the whole vacuum atomization chamber 2 is in a high-voltage state after high-voltage communication, which affects spraying and is unsafe. In particular, the upper access passage 3 is made of a hard, high temperature resistant material, preferably an insulating material.

In the embodiment of the present application, in order to maintain the vacuum state inside the vacuum atomizing chamber 2, the lower sealed sampling passage includes the following three designs: FIGS. 1 and 2 are embodiments of a first design; FIGS. 3 and 4 are embodiments of a second design; fig. 5 to 7 show a third embodiment.

In the embodiment shown in fig. 1-2, which provides a lower sealed sampling path with a vacuum valve 42, fig. 1 shows the sampling situation and fig. 2 shows the nebulization situation after sampling. In fig. 1, the sample injection spray needle 1 moves downwards, the vacuum valve 42 is opened, the grooved needle tip 13 penetrates through the vacuum valve 42 and pierces the self-healing sealing gasket 41 below the grooved needle tip to enter the sample solution 7, and stays in the sample solution 7 for 0.1-5 seconds, so that the grooved needle tip 13 is filled with the sample solution 7, wherein the material of the self-healing sealing gasket 41 can be rubber, silica gel plastic and the like. In fig. 2, the sample injection spray needle 1 moves upwards, when the grooved needle tip 13 moves to the position above the vacuum valve 42, the vacuum valve 42 is closed, the sample injection needle stays for 0-2 seconds, gas leaking into the vacuum atomization cavity 2 is pumped away by the mass spectrum preceding vacuum chamber 6, and the vacuum degree in the atomization cavity is basically consistent with the mass spectrum preceding vacuum degree. Preferably the needle residence time is 0.1 to 2 seconds. The sample injection spray needle 1 continues to move upwards until the high-voltage connecting device 8 on the needle arm is fully contacted with the high-voltage contact 11 and is electrified, the sample solution on the grooved needle tip 13 is subjected to electrospray under the drive of high voltage, and the spray time is usually 1-60 seconds; after the electric spraying is finished, the sample injection spray needle 1 starts to descend, the vacuum valve 42 is opened, the grooved needle tip 13 penetrates through the vacuum valve 42 and pierces the self-healing sealing gasket 41 below to be exposed outside, at this time, the used grooved needle tip 13 is pulled out by a manual or automatic device and replaced by a new needle (inserted into the needle grasping claw 43), and the sample analysis can be carried out in a circulating mode.

3-4 show a second embodiment of a vacuum electrospray ion source assembly in an embodiment of the present invention, which provides a lower sealed sampling channel with a vacuum valve 42 and a sealing sleeve 44 capable of forming a seal with a sample bottle, wherein the sample bottle is first tightly joined with the sealing sleeve 44 to form an airtight butt joint during sample injection, as shown in FIG. 3, and then the vacuum valve 42 is opened, the sample injection spray needle 1 goes down, the grooved needle tip 13 passes through the vacuum valve 42 and the lower sealing sleeve 44 to enter the sample solution 7, and stays in the sample solution for 0.1-5 seconds, so that the grooved needle tip 13 is fully filled with the sample solution; when the sample injection spray needle 1 starts to move upwards, as shown in fig. 4, when the grooved needle tip 13 runs above the vacuum valve 42 and enters the vacuum atomization cavity 2, the vacuum valve 42 is closed, the sample injection needle stays for 0-2 seconds (preferably for 0.1-2 seconds), so that gas leaking into the vacuum atomization cavity 2 is pumped away by the mass spectrum preceding stage vacuum chamber 6, and the vacuum degree in the atomization cavity is basically consistent with the mass spectrum preceding stage vacuum degree; the sample injection spray needle 1 continues to move upwards until a high-voltage contact 11 on a needle arm 12 is fully contacted with a high-voltage connecting device 8 and is electrified, the sample solution 7 on a grooved needle point 13 is subjected to electric spray under the drive of high voltage, and the spray time is generally controlled to be 1-60 seconds; and then, removing the sample, replacing the sample with a cleaning solution, hermetically butting a container in which the cleaning solution is located with a sealing sleeve 44, opening a vacuum valve 42, enabling the sample injection spray needle 1 to downwards move into the cleaning solution, and applying ultrasonic oscillation to the cleaning solution for 5-60 seconds. The sample injection spray needle 1 continues to move upwards and returns to the vacuum atomization cavity 2, and the vacuum valve 42 is closed after being rotated; and then the sample injection spray needle 1 continues to move downwards, a new detection sample is arranged below the sealing sleeve 44, and the above operations are repeated to finish detection.

Figures 5-7 show a third embodiment of a vacuum electrospray ion source assembly of the present invention having a lower sealed sampling channel with a downwardly extending sampling tube 45 (hollow) for sealing with the lower end of the needle arm 12, and a vacuum valve 42 mounted in the bottom of the sampling tube 45. As shown in fig. 6, the sample injection spray needle 1 is lowered until the grooved needle tip 13 approaches the vacuum valve 42, at which point the bottom of the needle arm 12 has entered the sample conduit 45 and sealed it to prevent vacuum leakage, and the vacuum valve 42 is opened. And the sample injection spray needle 1 continues to move downwards until the notch groove of the grooved needle tip 13 is soaked in the sample solution 7 and stays in the sample solution for 0.1-5 seconds, so that the notch groove of the grooved needle tip 13 is fully filled with the sample solution. Then the sample injection spray needle 1 rises, as shown in fig. 7, when the grooved needle tip 13 rises to above the vacuum valve 42 and the needle arm 12 still blocks the interior of the sampling conduit 45 to form a sealing structure, the vacuum valve 42 is closed, then the sample injection spray needle 1 rises to the highest position, the high voltage contact 11 on the needle arm 12 is fully contacted with the high voltage connecting device 8 and is electrified, and the spray is carried out for 1-60 seconds. The sample injection spray needle 1 is then lowered, the grooved needle tip 13 is exposed below through the vacuum valve 42, and the used grooved needle tip 13 is pulled out by a manual or automatic device and replaced with a new needle (inserted into the needle grasping claw 43), and the sample analysis can be performed cyclically.

The length of the sampling guide tube 45 provided by the embodiment of the invention is 1-10 mm longer than the total length of the grooved needle tip 13 and the needle grasping claw 43. The internal shape and size of the sampling catheter 45 are consistent with those of the needle insertion passage 31, the hollow central axis of the sampling catheter is overlapped with that of the needle insertion passage 31, the sampling catheter can be made of any material with good heat resistance and mechanical stability, and the insulation of the inner wall of the passage and the needle arm of the sample injection spray needle 1 is not required to be ensured. The sampling tube 45 may be made of any hard mechanically stable and heat resistant material, preferably stainless steel tubing.

In a specific embodiment, the vacuum electrospray ion source component is matched with a mass spectrometer and is fixed with the mass spectrometer in a relative position.

The vacuum electrospray ion source assembly has the following advantages: firstly, micro sampling and micro spraying are carried out, ions generated in atomized cloud are collected and enter a mass spectrum for separation and detection, and the ions are pumped away by a front stage vacuum chamber without ionization, cannot be deposited in a mass spectrometer, and cannot damage the vacuum in the mass spectrometer and cannot pollute the inside of the mass spectrometer; secondly, the micro ionization spraying is carried out in a vacuum state, the atomization effect can be extremely achieved, the sensitivity can be improved, and the matrix effect can be inhibited; the aperture of the ion collection channel can be enlarged to the extent that the vacuum atomization cavity and the mass spectrum foreline vacuum chamber are completely fused, so that the ion collection efficiency can reach 100 percent, and the sensitivity can be further improved; the sample introduction mode not only avoids the problems of splashing caused by introducing vacuum from normal pressure to the sample and blockage of a conveying pipeline due to refrigeration effect of vacuum spraying, but also facilitates the cleaning or replacement of the sample introduction needle, so that the sample introduction is rapid and convenient for automation; the invention avoids various problems of a liquid chromatography-mass spectrometry combined system, greatly simplifies the liquid mass spectrometry system and operation difficulty, greatly improves the analysis speed, and improves the flux of the instrument by 10-30 times; and a large amount of organic solvent is saved in sample treatment, so that the analysis cost can be reduced, and the pollution can be reduced.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit of the present invention are intended to be included therein.

Claims

1. The utility model provides a vacuum electrospray ion source subassembly, includes appearance spraying needle and vacuum atomization chamber, appearance spraying needle runs through vacuum atomization chamber can for vacuum atomization chamber reciprocates, and vacuum atomization chamber upper portion is provided with upper portion needle inlet passage, and the lower part is provided with the sealed sample access in lower part, wherein appearance spraying needle includes needle arm and trough of belt needle point, and the needle arm outside is located and with needle arm gas tightness joint, the sealed sample access in lower part are used for sealing vacuum atomization chamber lower part to upper portion needle inlet passage cover.

2. An electrospray ion source assembly according to claim 1, wherein said sample injection spray needle arm and slotted tip are integrally formed or detachably connected.

3. The vacuum electrospray ion source assembly according to claim 1, wherein said lower sealed sampling channel comprises a vacuum valve, further comprising a self-healing gasket and/or a conduit forming a gas tight joint with said needle arm.

4. The vacuum electrospray ion source assembly of claim 1, wherein said lower sealed sampling channel further comprises a slotted needle tip displacement device.

5. The vacuum electrospray ion source assembly of claim 1, wherein said lower sealed sampling channel further comprises a gland for sealing with a container of a sample to be tested.

6. The vacuum electrospray ion source assembly of any one of claims 1-5, wherein said needle arm is provided with a high voltage contact.

7. A mass spectrometry apparatus comprising a vacuum electrospray ion source assembly according to any one of claims 1-6.

8. A vacuum electrospray process comprising:

s1, a sample injection spray needle penetrates through a vacuum atomization cavity to move downwards, a grooved needle point is arranged at the bottom of the sample injection spray needle and enters a sample to be detected so that a notch groove on the grooved needle point is completely immersed in the sample to be detected,

s2, the sample injection spray needle moves upwards, and when the needle point of the groove is located in the vacuum atomization cavity and is 5-25 mm higher than the ion collection passage, high-voltage electricity is conducted to the sample injection spray needle for electrospray.

9. The method of claim 8, wherein the vacuum nebulization chamber is in sealing engagement with the needle arm of the sample injection spray needle through an upper needle access passage and a lower sealed sampling passage maintains a vacuum throughout the method.

10. The method according to claim 8, wherein in the step S2, the sample injection spray needle moves upwards and stops 0-2 seconds before the grooved needle tip reaches the center of the vacuum atomization chamber, so as to achieve vacuum balance.