Liquid chromatography-mass spectrometry system of thermal desorption gasification electrospray interface and control method

Abstract

The invention provides a liquid chromatography-mass spectrometry system of a thermal desorption electrospray ionization interface and a control method, and the system comprises an electrospray generation assembly, a mass spectrometer, a liquid chromatographic column assembly and a thermal desorption assembly, a spray outlet of the electrospray generation assembly and a mass spectrum inlet of the mass spectrometer are opposite in the horizontal direction and are spaced by a first preset distance; the liquid chromatographic column assembly comprises a sample tube, and the sample tube and the thermal desorption gasification assembly are located between the spray outlet and the mass spectrum inlet; the thermal desorption gasification assembly comprises a gasification chamber, the sample tube is located above the gasification chamber, an opening of the sample tube and an opening of the gasification chamber are oppositely arranged in the vertical direction, a sample outlet of the sample tube extends into the bottom of the gasification chamber, and the liquid chromatographic column assembly conveys a sample solution into the gasification chamber; the opening of the vaporizing chamber is positioned in a range of a second preset distance below a center connecting line of the spray outlet and the mass spectrum inlet, so that the mass spectrum signal intensity detected by the mass spectrometer meets a preset condition.

Description

Technical Field

[0001] The present invention belongs to the technical field of chromatography-mass spectrometry analysis, and in particular relates to a liquid chromatography-mass spectrometry system of a thermal desorption gasification electrospray ionization interface and a control method thereof. Background Art

[0002] Electrospray ionization mass spectrometry (ESI-MS), one of the most widely used mass spectrometry techniques, is used in a variety of fields, including environmental testing, pesticide residue detection, medicine, biology, chemistry, national defense, and forensic medicine. It possesses strong qualitative and quantitative capabilities. However, drawbacks such as mass discrimination and matrix interference severely reduce ESI-MS detection capabilities. Therefore, in most cases, sample separation and purification are required before ESI-MS detection.

[0003] High-Performance Liquid Chromatography (HPLC) offers excellent sample separation capabilities. The HPLC column can separate compounds in a sample one by one, and its outlet can be directly connected to an electrospray mass spectrometer. Therefore, HPLC and electrospray mass spectrometers are often used in tandem. This LC-MS technique effectively overcomes mass discrimination and matrix interference, significantly enhancing the qualitative and quantitative capabilities of electrospray mass spectrometry.

[0004] However, there are also serious mismatches between ESI-MS and HPLC, which can lead to two serious problems:

[0005] Question 1: Liquid chromatography often uses inorganic salts as buffer solutions to improve chromatographic peak shape and increase chromatographic separation. However, inorganic salts cannot be used as buffer solutions to improve chromatographic peak shape and increase chromatographic separation in liquid chromatography-mass spectrometry systems. Inorganic salt solutions easily precipitate crystals in the mass spectrometer pipeline, blocking the mass spectrometer pipeline and severely suppressing the mass spectrometer signal. Therefore, the mass spectrometer prohibits the use of inorganic salt solutions and can only use volatile organic salts as buffer salts. However, this change not only reduces the scope of use of liquid chromatography buffer salts, but the buffering capacity of organic salts is generally poor, seriously affecting the chromatographic peak shape and separation value, thereby greatly reducing the performance of liquid chromatography.

[0006] Question 2: When a liquid chromatograph uses a normal phase column for separation and purification, solvents such as n-hexane, acetone, and dichloromethane are usually used as mobile phases. However, the polarity of these types of solvents is too low and they cannot provide protons in electrospray mass spectrometry, resulting in too low electrospray mass spectrometry signals. Therefore, normal phase columns cannot be used in conjunction with electrospray mass spectrometry. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a liquid chromatography-mass spectrometry system and control method for a thermal desorption gasification electrospray ionization interface. The liquid chromatography-mass spectrometry system for a thermal desorption gasification electrospray ionization interface can replace the liquid chromatography mobile phase with a solvent system acceptable to the mass spectrometer, thereby being applied in a liquid chromatography-mass spectrometry system.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] A liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface, comprising:

[0010] An electrospray generating assembly and a mass spectrometer, wherein the spray outlet of the electrospray generating assembly and the mass spectrometer inlet of the mass spectrometer are horizontally opposite to each other and are separated by a first preset distance;

[0011] The electrospray generating assembly sprays ionized spray toward the mass spectrometer inlet through the spray outlet;

[0012] A liquid chromatography column assembly and a thermal desorption gasification assembly, wherein the liquid chromatography column assembly includes a sample tube, and the sample tube and the thermal desorption gasification assembly are both located between the spray outlet and the mass spectrometer inlet;

[0013] The thermal desorption vaporization assembly includes a vaporization chamber, the sample tube is located above the vaporization chamber, and the sample tube and the opening of the vaporization chamber are arranged opposite to each other in a vertical direction, the sample outlet of the sample tube extends into the bottom of the vaporization chamber, and the liquid chromatography column assembly transports the sample solution into the vaporization chamber;

[0014] The opening of the vaporization chamber is located within a second preset distance below a center line connecting the spray outlet and the mass spectrometer inlet, so that the intensity of the mass spectrometer signal detected by the mass spectrometer meets a preset condition.

[0015] Preferably, a first preset distance range between the spray outlet of the electrospray generating assembly and the mass spectrometer inlet in the horizontal direction is 0.5 cm-1.5 cm.

[0016] Preferably, the second preset distance ranges from 0.5 cm to 1.5 cm.

[0017] Preferably, the vaporization chamber is spherical, and the diameter of the sphere ranges from 0.30 cm to 0.44 cm;

[0018] Alternatively, the vaporization chamber includes an arc-shaped side wall and a bottom surface connected to the arc-shaped side wall, and the bottom surface is a plane;

[0019] The diameter of the arc-shaped side wall ranges from 0.30 cm to 0.44 cm, and the depth of the vaporization chamber ranges from 0.20 cm to 0.40 cm.

[0020] Preferably, the liquid chromatography column assembly comprises a liquid chromatography column and a first peek tube, wherein one end of the first peek tube is connected to the sample tube, and the other end is connected to the liquid chromatography column.

[0021] A method for controlling a liquid chromatography-mass spectrometry system with a thermal desorption / gasification electrospray ionization interface, using the liquid chromatography-mass spectrometry system with the thermal desorption / gasification electrospray ionization interface, comprising:

[0022] Turn on the mass spectrometer and start scanning;

[0023] Turning on the electrospray generating assembly so that the spray outlet of the electrospray generating assembly starts to spray ionized spray, and adjusting the position of the electrospray generating assembly from the mass spectrometer so that the mass spectrometer signal detected by the mass spectrometer reaches the strongest;

[0024] heating the vaporization chamber to a preset temperature;

[0025] Turning on the liquid chromatography column assembly, the liquid chromatography column assembly delivers a sample solution into the vaporization chamber through a sample outlet of the sample tube. The liquid in the vaporization chamber is instantly vaporized after being heated. The vaporized target compound leaves the vaporization chamber and rises to the inlet of the mass spectrometer, contacts and dissolves in the ionized spray, and enters the mass spectrometer for detection.

[0026] Record mass spectrometric data.

[0027] Preferably, the spray voltage of the electrospray generating assembly ranges from 2.5 kV to 5 kV.

[0028] Preferably, the heated temperature range of the gasification chamber is 100°C-300°C.

[0029] Preferably, the sample solution includes at least one of acetone, n-hexane, dichloromethane and a salt-containing solvent.

[0030] Compared to existing technologies, the present invention offers the following advantages: The liquid chromatography column assembly of the present invention delivers the sample solution to the bottom of the vaporization chamber, and the sample outlet of the sample tube extends into the bottom of the vaporization chamber. Therefore, the sample solution is located at the bottom and quickly contacts the vaporization chamber after flowing out of the sample outlet. Target compounds vaporized from the sample solution move upward between the spray outlet and the mass spectrometer inlet, without interfering with the upwardly evaporating target compound vapor, thus achieving continuous sampling.

[0031] The sample solution evaporates quickly upon contact with the bottom of the vaporization chamber, preventing a large amount of sample solution overload within a short period of time. This lack of sample solution accumulation reduces the requirements for the vaporization chamber, allowing for a smaller chamber size than currently available.

[0032] In the present invention, the sample solution is directly applied to the bottom of the vaporization chamber for evaporation and gasification without forming droplets, and there is no problem of the sample solution being stuck at the inlet of the vaporization chamber and unable to enter.

[0033] When the liquid chromatography column assembly transports a sample solution containing inorganic salts into the vaporization chamber, most of the inorganic salts are heated and crystallized at the bottom of the vaporization chamber. After the sample solution is vaporized, it becomes the target compound, which is dissolved in the ionization spray. A small amount of evaporated inorganic salts are discharged from the ionization spray because they are insoluble in organic solvents, avoiding entering the mass spectrometer and contaminating the instrument pipeline, and also avoiding the charge in the ionization spray being occupied by the inorganic salts, thereby ensuring that the target compound is ionized by the charge in the ionization spray. The mass spectrometer detects the target compound, and the inorganic salts will not affect the intensity of the detected mass spectrometry signal.

[0034] The electrospray generating assembly can spray a solvent spray with voltage toward the mass spectrometer inlet of the mass spectrometer. The spray outlet and the mass spectrometer inlet are opposite to each other in the horizontal direction and are separated by a first preset distance, and the opening of the vaporization chamber is located within a second preset distance range below the center line connecting the spray outlet and the mass spectrometer inlet. Within this size range, it can be ensured that the vaporized target compound can be fully integrated with the ionized spray ejected from the spray outlet, ionized by the charge in the ionized spray, and the mass spectrometer signal intensity detected by the mass spectrometer is the strongest. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the structure of the liquid chromatography-mass spectrometry system of the thermal desorption gasification electrospray ionization interface in the present invention;

[0036] Figure 2 For the present invention Figure 1 An enlarged view of the structure at I;

[0037] Figure 3 The selected ion chromatogram of atrazine analyzed by liquid chromatography-mass spectrometry system with thermal desorption vaporization electrospray ionization interface under the condition of 20 mol / L sodium dihydrogen phosphate solution in the present invention;

[0038] Figure 4 The mass spectrum of atrazine in the liquid chromatography-mass spectrometry system with thermal desorption vaporization electrospray ionization interface of the present invention;

[0039] Figure 5 The mass spectrometry results of the present invention are obtained by introducing an n-hexane solution of atrazine into a liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface for detection;

[0040] Figure 6 The mass spectrometry results of the present invention are obtained by introducing an acetone solution of atrazine into a liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface for detection;

[0041] Figure 7 This is the mass spectrometry result of introducing a dichloromethane solution of atrazine into a liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface for detection in the present invention.

[0042] Among them, 1. Electrospray generation component; 11. Electrospray generator; 12. Metal electrode; 13. Spray outlet; 2. Mass spectrometer; 21. Mass spectrometer inlet; 3. Liquid chromatography column component; 31. Sample outlet; 32. Liquid chromatography column; 33. First peek tube; 34. Sample tube; 4. Thermal desorption vaporization component; 41. Vaporization chamber; 42. Heating component; 5. Second peek tube. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0046] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0047] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0048] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0049] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0050] like Figure 1 and Figure 2 As shown, this embodiment provides a liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface, comprising an electrospray generator assembly 1, a mass spectrometer 2, a liquid chromatography column assembly 3, and a thermal desorption vaporization assembly 4. The spray outlet 13 of the electrospray generator assembly 1 and the mass spectrometer inlet 21 of the mass spectrometer 2 are horizontally aligned and separated by a first predetermined distance. The electrospray generator assembly 1 sprays an ionized spray through the spray outlet 13 toward the mass spectrometer inlet 21.

[0051] The liquid chromatography column assembly 3 includes a sample tube 34 , and the sample tube 34 and the thermal desorption gasification assembly 4 are located between the spray outlet 13 and the mass spectrometer inlet 21 .

[0052] The thermal desorption vaporization assembly 4 includes a vaporization chamber 41, the sample tube 34 is located above the vaporization chamber 41, and the openings of the sample tube 34 and the vaporization chamber 41 are arranged opposite each other in the vertical direction. The sample outlet 31 of the sample tube 34 extends into the bottom of the vaporization chamber 41, and the liquid chromatography column assembly 3 transports the sample solution into the vaporization chamber 41.

[0053] The opening of vaporization chamber 41 is located between spray outlet 13 and mass spectrometer inlet 21, and is also located within a second predetermined distance below a line connecting the centers of spray outlet 13 and mass spectrometer inlet 21, so that the intensity of the mass spectrometer signal detected by the mass spectrometer meets a predetermined condition. In this embodiment, the first predetermined distance between spray outlet 13 and mass spectrometer inlet 21, as well as the second predetermined distance between the opening of the vaporization chamber and the line connecting the centers of spray outlet 13 and mass spectrometer inlet 21, are adjusted to maximize the intensity of the mass spectrometer signal detected by the mass spectrometer.

[0054] In conventional technical solutions, the sample is introduced into the vaporization chamber 41 by a dropwise method, such as the technical solution in patent ZL201811403019.5. Specifically, the sample solution is dripped into the upper inlet of the vaporization chamber 41. This method is suitable for rapid analysis, but not suitable for continuous sampling.

[0055] The droplets of sample solution added to the vaporization chamber 41 and the vapor of the sample that is vaporized and rises after addition will interfere with each other. Secondly, after the sample solution is vaporized and forms droplets, it will drip into the vaporization chamber 41 again, forming discontinuous sampling, resulting in large fluctuations in the mass spectrometry signal and an increase in the chromatographic dead volume.

[0056] When sample solution droplets are added to vaporization chamber 41, an excess of sample quickly forms within it. To meet the test requirements, the performance requirements for vaporization chamber 41 were further increased, requiring the size of vaporization chamber 41 to precisely match the size of the droplets. This increases the heating area to rapidly vaporize the droplets. If vaporization chamber 41 is too small, the droplets may become stuck at the entrance and unable to enter the chamber. If vaporization chamber 41 is too large, the droplets may not fully contact the surrounding areas of the chamber, reducing the efficiency of heating and vaporizing the droplets.

[0057] In this embodiment, the liquid chromatography column assembly 3 delivers the sample solution to the bottom of the vaporization chamber 41, and the sample outlet 31 of the sample tube 34 extends into the bottom of the vaporization chamber 41. Therefore, the sample solution is located at the bottom and quickly contacts the vaporization chamber 41 after flowing out of the sample outlet 31. After vaporization, the sample solution moves upward to between the spray outlet 13 and the mass spectrometer inlet 21. The sample solution does not interfere with the upward evaporation of the target compound vapor, achieving continuous sampling.

[0058] The sample solution evaporates quickly after contacting the bottom of the vaporization chamber 41, and a large amount of sample solution overload is not formed in a short time. Without the accumulation of sample solution, the requirements for the vaporization chamber 41 are reduced, and a smaller size of the vaporization chamber 41 can be used than in the prior art.

[0059] In this embodiment, the sample solution is directly applied to the bottom of the vaporization chamber 41 to evaporate and gasify without forming droplets. There is no problem of the sample solution being stuck at the inlet of the vaporization chamber 41 and unable to enter.

[0060] When the liquid chromatography column assembly 3 transports a sample solution containing inorganic salts into the vaporization chamber 41, most of the inorganic salts are heated and crystallized at the bottom of the vaporization chamber 41. The target compound after the sample solution is vaporized is dissolved in the ionization spray. A small amount of evaporated inorganic salts are discharged from the ionization spray because they are insoluble in organic solvents, avoiding entering the mass spectrometer 2 to contaminate the instrument pipeline, and also avoiding the charge in the ionization spray being occupied by the inorganic salts, thereby ensuring that the target compound is ionized by the charge in the ionization spray, and the mass spectrometer 2 detects the target compound. The inorganic salts will not affect the intensity of the detected mass spectrometry signal.

[0061] The electrospray generating assembly 1 can spray a solvent spray with voltage toward the mass spectrometer inlet 21 of the mass spectrometer 2. The spray outlet 13 and the mass spectrometer inlet 21 are opposite to each other in the horizontal direction and are separated by a first preset distance, and the opening of the vaporization chamber 41 is located within a second preset distance range below the center line connecting the spray outlet 13 and the mass spectrometer inlet 21. Within this size range, it can be ensured that the vaporized target compound can be fully integrated with the ionized spray sprayed from the spray outlet 13, and ionized by the charge in the ionized spray, so that the mass spectrometer signal intensity detected by the mass spectrometer is the strongest.

[0062] Preferably, the first preset distance between the spray outlet 13 of the electrospray generating assembly 1 and the mass spectrometer inlet 21 along the horizontal direction ranges from 0.5 cm to 1.5 cm.

[0063] The ionized spray ejected from the spray outlet 13 of the electrospray generating assembly 1 moves to the mass spectrometer inlet 21. During this journey, the ionized spray can fully dissolve with the target compound to form small droplets. At this time, the mass spectrometer signal intensity detected by the mass spectrometer 2 is the strongest.

[0064] Preferably, the second preset distance is in the range of 0.5 cm to 1.5 cm, so as to ensure that the intensity of the mass spectrometry signal detected by the mass spectrometer is the strongest.

[0065] Preferably, the electrospray generating assembly 1 comprises an electrospray generator 11 and a spray capillary connected to the output end of the electrospray generator 11. The spray generated by the electrospray generator 11 is sprayed toward the mass spectrometer inlet 21 through the spray capillary.

[0066] Preferably, the electrospray generating assembly 1 further includes a metal electrode 12 inserted into the electrospray generator 11. After the solvent is introduced into the electrospray generator 11, the upper end of the metal electrode 12 inserted into the electrospray generator 11 can contact the solvent in the electrospray generator 11 and turn on the external power supply to form a current loop with the mass spectrometer 2. The voltage range of the metal electrode 12 is 2.5 kV-5 kV.

[0067] Preferably, the vaporization chamber 41 is spherical, with a diameter ranging from 0.30 cm to 0.44 cm. The vaporization chamber 41 has a small inner diameter and a simple structure, which reduces experimental difficulty. The specific dimensions of the vaporization chamber 41 are determined based on the desired vaporization rate.

[0068] Alternatively, the vaporization chamber 41 includes an arcuate sidewall and a bottom surface connected to the arcuate sidewall, wherein the bottom surface is a plane. The diameter of the arcuate sidewall ranges from 0.30 cm to 0.44 cm, and the depth of the vaporization chamber 41 ranges from 0.20 cm to 0.40 cm.

[0069] The arc-shaped sidewall of the vaporization chamber 41 has a small diameter and a small depth, resulting in a simple structure and reduced experimental difficulty. The specific dimensions of the vaporization chamber 41 are determined based on the desired vaporization speed.

[0070] Preferably, the mass spectrometer 2 is any one of a quadrupole mass spectrometer, an ion trap mass spectrometer, an orbitrap mass spectrometer, and a time-of-flight mass spectrometer.

[0071] Preferably, the thermal desorption gasification component 4 further includes a heating component 42 , and the gasification chamber 41 is placed on the heating component 42 and heated by the heating component 42 .

[0072] Preferably, the heated temperature of the gasification chamber 41 ranges from 100°C to 300°C.

[0073] The liquid chromatography column assembly 3 includes a liquid chromatography column 32 and a first peek tube 33 . One end of the first peek tube 33 is connected to the sample tube 34 , and the other end is connected to the liquid chromatography column 32 .

[0074] The outlet of the liquid chromatography column 32 is connected to the first peek tube 33 and the sample tube 34 in sequence. Since the sample tube 34 is a capillary tube and its structure is fragile, the first peek tube 33 is used to connect the liquid chromatography column 32 and the sample tube 34.

[0075] Preferably, the sample tube 34 is a capillary tube, and the sample tube 34 is continuously fed into the vaporization chamber 41. The capillary tube is made of metal or quartz.

[0076] Preferably, the inlet of the electrospray generating assembly 1 is connected to the external solvent via the second peek tube 5. The solvent is introduced into the electrospray generating assembly 1 via the second peek tube 5.

[0077] The control method of the liquid chromatography-mass spectrometry system of the thermal desorption gasification electrospray ionization interface in this embodiment includes:

[0078] Turn on mass spectrometer 2 and start scanning;

[0079] Turn on the electrospray generating assembly 1, and the spray outlet 13 of the electrospray generating assembly 1 starts to spray ionized spray, and adjust the position of the electrospray generating assembly 1 from the mass spectrometer 2 so that the mass spectrometer signal detected by the mass spectrometer 2 reaches the strongest;

[0080] heating the vaporization chamber 41 to a preset temperature;

[0081] The liquid chromatography column assembly 3 is turned on and the sample solution is delivered to the vaporization chamber 41 through the sample outlet 31 of the sample tube 34. The liquid in the vaporization chamber 41 is instantly vaporized after being heated. The vaporized target compound leaves the vaporization chamber 41 and rises to the inlet of the mass spectrometer 2. It contacts and dissolves in the ionized spray and enters the mass spectrometer 2 for detection.

[0082] By recording the mass spectrum data, the liquid chromatography-mass spectrometry data of the liquid chromatography-mass spectrometry system using the thermal desorption vaporization electrospray ionization interface of this embodiment can be obtained.

[0083] Preferably, the spray voltage of the electrospray generating assembly 1 ranges from 2.5 kV to 5 kV. The voltage value of the electrospray generating assembly 1 is determined according to the experimental signal of the mass spectrometer 2, with the strongest mass spectrum signal of the target compound detected by the mass spectrometer 2 being the standard.

[0084] Preferably, the electrospray solvent in the electrospray generating assembly 1 includes any one or more of water, methanol, and acetonitrile.

[0085] The sample solution includes a sample and at least one of acetone, n-hexane, dichloromethane and a salt-containing solvent. The target compound after vaporization of the sample solution is dissolved in the ionization spray.

[0086] Specifically, in this embodiment, a liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface was used to detect atrazine in a sample containing an inorganic buffer salt, acetone, n-hexane, and dichloromethane solution.

[0087] The experiment used a liquid chromatography system and a mass spectrometer 2. The spray voltage of the electrospray generating assembly 1 was 4 kV, and the generated spray flow rate was 5 μL / min.

[0088] The heating temperature of the vaporization chamber 41 was 120° C., and continuous injection was used for the liquid chromatography column assembly 3 to inject the sample into the vaporization chamber 41. The concentration of atrazine in the experiment was 1 mg / L.

[0089] Atrazine was analyzed by liquid chromatography-mass spectrometry (LC-MS) with a thermal desorption vaporization electrospray ionization interface. The mobile phase was a 20 mol / L sodium dihydrogen phosphate aqueous solution: methanol in a ratio of 3:7. The injection volume was 5 μL, the atrazine concentration was 1 mg / L, and a Waters C18 reversed-phase column was used. The column temperature was 40 degrees. Methanol was selected as the electrospray solvent to exclude a small amount of inorganic salts from the electrospray solvent system.

[0090] Figure 3 Selected ion chromatogram for the analysis of atrazine in 20 mol / L sodium dihydrogen phosphate solution using a liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface.

[0091] It can be seen that the peak width of atrazine is controlled within 10 seconds, indicating that the sample solution is rapidly vaporized upon entering the vaporization chamber 41 , and the target compound does not stay in the vaporization chamber 41 but quickly enters the mass spectrometer 2 for detection.

[0092] at the same time, Figure 3 The signal intensity of atrazine molecules in the spectrum reached 24000. This shows that the LC-MS system with thermal desorption vaporization electrospray ionization interface in the LC-MS process can effectively eliminate the influence of inorganic salts in the solution on the mass spectrometry detection effect. At the same time, during the experiment, it can be seen that a large amount of white powder is deposited in the vaporization chamber 41, which means that most of the sodium dihydrogen phosphate did not vaporize with the sample solution, but was heated in the vaporization chamber 41 to precipitate solids, thus preventing salt ions from entering the mass spectrum. The corresponding mass spectrum is shown in Figure 2. Figure 4 As shown, the mass spectrum peak of atrazine is the base peak, i.e. m / z 216 in the figure, and the signal is strong and is not suppressed by inorganic salts.

[0093] This example demonstrates that a LC-MS system using a thermal desorption / electrospray ionization interface can convert the inorganic salt mobile phase from a liquid chromatography column into a solvent system acceptable to mass spectrometer 2, resolving the problem that liquid chromatography using inorganic buffer salts cannot be coupled with mass spectrometry. Atrazine solutions in n-hexane, acetone, and dichloromethane were introduced into a LC-MS system using a thermal desorption / electrospray ionization interface for detection. The electrospray solvents were acetonitrile and water in a ratio of 80:20. The mass spectrometric results obtained are shown in Figure 2. Figure 5-Figure 7 As shown, the mass spectrum peaks of atrazine are all base peaks with strong signals, indicating that these low-polarity solvents can be replaced by electrospray solvents acetonitrile and water in the liquid chromatography-mass spectrometry system of the thermal desorption vaporization electrospray ionization interface without affecting the ionization of the target compound. These solvents are used as normal phase chromatography mobile phases, proving that the thermal desorption vaporization component 4 and liquid chromatography column component 3 can serve as an interface for normal phase chromatography and mass spectrometry, solving the long-standing problem of the inability to combine normal phase chromatography and mass spectrometry.

[0094] The electrospray generating assembly 1 in this embodiment uses an electrospray solvent such as water, methanol, or acetonitrile. After evaporation, the solvent in the sample solution is replaced by the ionized spray sprayed by the electrospray generating assembly 1. The vaporized target compound is absorbed into the ionized spray without affecting the ionization of the target compound. Solvents such as acetone, n-hexane, and dichloromethane used in normal-phase chromatography can also be rapidly evaporated and replaced by the ionized spray. Therefore, normal-phase chromatography can also be coupled with electrospray mass spectrometry, resolving the problem of inability to combine normal-phase chromatography and electrospray mass spectrometry.

[0095] The thermal desorption vaporization electrospray ionization system used in this embodiment is simple in device and made of a wide range of materials. It can be set up, used, and cleaned at any time. At the same time, the instrument parameters are easy to optimize, and rapid high-throughput analysis can be achieved.

[0096] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A liquid chromatography-mass spectrometry system with a thermal desorption gasification electrospray ionization interface, characterized in that: include: An electrospray generating assembly (1) and a mass spectrometer (2), wherein the spray outlet (13) of the electrospray generating assembly (1) and the mass spectrometer inlet (21) of the mass spectrometer (2) are opposite to each other in a horizontal direction and are separated by a first preset distance; The electrospray generating assembly (1) sprays ionized spray toward the mass spectrometer inlet (21) through the spray outlet (13); A liquid chromatography column assembly (3) and a thermal desorption gasification assembly (4), wherein the liquid chromatography column assembly includes a sample tube (34), and the sample tube (34) and the thermal desorption gasification assembly (4) are both located between the spray outlet (13) and the mass spectrometer inlet (21); The thermal desorption gasification component (4) includes a gasification chamber (41), the sample tube (34) is located above the gasification chamber (41), and the openings of the sample tube (34) and the gasification chamber (41) are arranged opposite to each other in a vertical direction, the sample outlet (31) of the sample tube (34) extends into the bottom of the gasification chamber (41), and the liquid chromatography column component (3) transports the sample solution into the gasification chamber (41); The opening of the vaporization chamber (41) is located within a second preset distance below a center line connecting the spray outlet (13) and the mass spectrometer inlet (21), so that the intensity of the mass spectrometer signal detected by the mass spectrometer meets a preset condition.

2. The liquid chromatography-mass spectrometry system with thermal desorption gasification electrospray ionization interface according to claim 1, characterized in that: A first preset distance range between the spray outlet (13) of the electrospray generating assembly (1) and the mass spectrometer inlet (21) in the horizontal direction is 0.5 cm to 1.5 cm.

3. The liquid chromatography-mass spectrometry system with thermal desorption gasification electrospray ionization interface according to claim 1, characterized in that: The second preset distance ranges from 0.5 cm to 1.5 cm.

4. The liquid chromatography-mass spectrometry system with a thermal desorption gasification electrospray ionization interface according to claim 1, characterized in that: The vaporization chamber (41) is spherical, and the diameter of the sphere ranges from 0.30 cm to 0.44 cm; Alternatively, the vaporization chamber (41) comprises an arc-shaped side wall and a bottom surface connected to the arc-shaped side wall, and the bottom surface is a plane; The diameter of the arc-shaped side wall ranges from 0.30 cm to 0.44 cm, and the depth of the vaporization chamber (41) ranges from 0.20 cm to 0.40 cm.

5. The liquid chromatography-mass spectrometry system with a thermal desorption vaporization electrospray ionization interface according to any one of claims 1 to 4, characterized in that: The liquid chromatography column assembly (3) comprises a liquid chromatography column (32) and a first peek tube (33), wherein one end of the first peek tube (33) is connected to a sample tube (34), and the other end is connected to the liquid chromatography column (32).

6. A method for controlling a liquid chromatography-mass spectrometry system with a thermal desorption gasification electrospray ionization interface, characterized in that: A liquid chromatography-mass spectrometry system using the thermal desorption vaporization electrospray ionization interface according to any one of claims 1 to 5, comprising: Turn on the mass spectrometer (2) and start scanning; The electrospray generating assembly (1) is turned on, and the spray outlet (13) of the electrospray generating assembly (1) starts to spray ionized spray, and the position of the electrospray generating assembly (1) and the mass spectrometer (2) are adjusted so that the mass spectrometer signal detected by the mass spectrometer (2) reaches the strongest; heating the vaporization chamber (41) to a preset temperature; The liquid chromatography column assembly (3) is turned on, and the liquid chromatography column assembly (3) transports a sample solution into the vaporization chamber (41) through the sample outlet (31) of the sample tube (34). The liquid entering the vaporization chamber (41) is instantly vaporized after being heated. The vaporized target compound leaves the vaporization chamber (41) and rises to the inlet of the mass spectrometer (2), contacts the ionized spray and dissolves in the ionized spray, and enters the mass spectrometer (2) for detection; Record mass spectrometric data.

7. The control method of the liquid chromatography-mass spectrometry system of the thermal desorption gasification electrospray ionization interface according to claim 6, characterized in that: The spray voltage of the electrospray generating assembly (1) ranges from 2.5 kV to 5 kV.

8. The control method of the liquid chromatography-mass spectrometry system of the thermal desorption gasification electrospray ionization interface according to claim 6, characterized in that: The heated temperature range of the gasification chamber (41) is 100°C-300°C.

9. The control method of the liquid chromatography-mass spectrometry system of the thermal desorption gasification electrospray ionization interface according to claim 6, characterized in that: The sample solution includes at least one of acetone, n-hexane, dichloromethane and a salt-containing solvent.

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