An ultrasonic atomization and flame-assisted thermal ionization method

Abstract

This invention discloses an ultrasonic atomization and flame-assisted thermal ionization method. The method uses the port of the mass spectrometer injection channel, heated by a flame, as the ion source. The sample solution in the sample container is atomized using an ultrasonic atomization device, and the atomized sample moves to the port of the mass spectrometer injection channel for ionization. The thermal ionization method provided by this invention has advantages such as low cost, ease of implementation, wide applicability to various solvents, ability to analyze both polar and non-polar compounds, and the ability to analyze samples at the milliliter level.

Description

Technical Field

[0001] This invention relates to an ultrasonic atomization and flame-assisted thermal ionization method, belonging to the field of mass spectrometry analysis technology. Background Technology

[0002] Mass spectrometry (MS) is an analytical tool for measuring the mass-to-charge ratio of ions. It features high sensitivity, fast analysis speed, and wide applicability. Currently, mass spectrometry technology is widely used in many fields such as chemistry and chemical engineering, biology and life sciences, medicine, pharmacy, materials science, food science, and environmental science.

[0003] The principle of mass spectrometry is to ionize the components of a sample in an ion source, generating ions with different mass-to-charge ratios. These ions are then separated in a mass analyzer and detected by a detector to obtain mass information. The first step in mass spectrometry sample detection is the ionization of the analyte; therefore, ionization technology is crucial for mass spectrometry analysis. The generation of compound ions is closely related to the physicochemical properties of the compound, and currently, there is no universal ionization technique that can efficiently ionize all types of organic compound structures.

[0004] Ion sources, as a crucial component of mass spectrometry and mass spectrometry imaging instruments, have long been a hot topic in the field of mass spectrometry analysis. Traditional ion sources operate under vacuum or atmospheric pressure closed conditions, such as electron impact ionization (EI) ion sources, matrix-assisted laser desorption / ionization (MALDI) ion sources, electrospray ionization (ESI) ion sources, and atmospheric pressure chemical ionization (APCI) ion sources. The limitations of these techniques on sample properties and the inherent limitations of their ionization mechanisms necessitate complex pretreatment processes for many complex matrix samples before analysis. To address these issues, open-loop ionization techniques have emerged and have gradually become a research hotspot in the past decade.

[0005] Open-type ionization mass spectrometry (AI-MS) was first proposed by Cooks' group in 2004. It allows for direct analysis of samples in an open atmospheric pressure environment, requiring minimal or no sample pretreatment. While maintaining the high sensitivity and speed of traditional mass spectrometry, this technique also offers advantages such as ease of operation, in-situ real-time analysis, high throughput, and environmental friendliness, greatly simplifying the analytical workflow and improving the usability of mass spectrometry instruments.

[0006] In addition, atmospheric pressure flame ionization mass spectrometry (APFMS) is a novel open-type ionization mass spectrometry technique with high sensitivity. However, existing APFMS techniques require direct contact between the sample and the flame for analysis, making it impossible to avoid sample combustion and thermal decomposition. Furthermore, in an open atmospheric pressure environment, the flame morphology is difficult to maintain stability for extended periods, resulting in unstable mass spectrometry signals and making the detection of some low-polarity compounds / solvents difficult. Summary of the Invention

[0007] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a method for ultrasonic atomization and flame-assisted thermal ionization.

[0008] To solve the above problems, the present invention adopts the following technical solution:

[0009] An ultrasonic atomization and flame-assisted thermal ionization method uses the port of the mass spectrometer injection channel heated by a flame as the ion source, and uses an ultrasonic atomization device to atomize the sample solution in the sample container. The atomized sample moves to the port of the mass spectrometer injection channel and is ionized.

[0010] One embodiment of the thermal ionization method includes the following steps:

[0011] a) A flame is generated by a flame generator, and the port of the mass spectrometer injection channel is located in or near the flame generated by the flame generator, and the port of the mass spectrometer injection channel is heated by the flame.

[0012] b) Add the sample solution to be tested into the sample container, with the outlet end of the sample container facing upward and below the port of the mass spectrometer injection channel, and place the sample container on the ultrasonic nebulizer.

[0013] c) Turn on the ultrasonic nebulizer. The ultrasonic nebulizer atomizes the sample solution to be tested through the sample container. After the atomized sample leaves the sample container, it moves to the port of the mass spectrometer injection channel and is ionized.

[0014] In a preferred embodiment, the flame generating device includes a hydrogen generator and a flame generating tube connected by a pipeline, wherein the outlet end of the flame generating tube is the flame ignition end, and the flame ignition end is located near the port of the mass spectrometer sample introduction channel.

[0015] In a preferred embodiment, a gas flow regulating valve is provided on the pipeline connecting the hydrogen generator and the flame generating tube.

[0016] In a preferred embodiment, the flame ignition end is made of a high-temperature resistant material, including but not limited to stainless steel.

[0017] In a preferred embodiment, the distance between the port of the mass spectrometer injection channel and the flame ignition end is 2–13 mm.

[0018] In one embodiment, the port of the mass spectrometer sample introduction channel is an ion transmission tube, and the length of the ion transmission tube is 5 to 10 millimeters.

[0019] In a preferred embodiment, the temperature of the port of the mass spectrometer injection channel after being heated by a flame is 300–800°C.

[0020] One embodiment includes, but is not limited to, test tubes, liquid chromatography vials, and derivatization vials.

[0021] In one embodiment, the ultrasonic atomizing device includes an ultrasonic atomizer and an acoustic energy transfer medium, wherein the acoustic energy transfer medium is located between the ultrasonic atomizer and the sample container.

[0022] In a preferred embodiment, the ultrasonic atomizer includes, but is not limited to, a piezoelectric ceramic atomizing plate, and the acoustic energy transmission medium includes, but is not limited to, ultrasonic coupling gel.

[0023] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0024] 1. The ultrasonic atomization and flame-assisted thermal ionization method provided by the present invention heats the port of the mass spectrometer sample inlet channel with a flame, and uses the port of the mass spectrometer sample inlet channel heated by the flame as an ion source to ionize the sample, so that the sample does not directly contact the flame, thereby effectively reducing thermal decomposition and making the mass spectrometry signal more stable.

[0025] 2. In the ultrasonic atomization and flame-assisted thermal ionization method provided by the present invention, the sample is not placed directly on the ultrasonic atomization device for ultrasonic atomization, but is placed in a sample container and then placed on the ultrasonic atomization device. The ultrasonic atomization device atomizes the sample through the sample container, thereby effectively reducing cross-contamination and improving analytical throughput.

[0026] 3. The ultrasonic atomization and flame-assisted thermal ionization method provided by this invention is applicable to a wide range of solvents, has low selectivity for the sample to be tested, and can analyze polar and non-polar compounds and samples with milliliter-level volumes. Furthermore, it does not require complex sample pretreatment, making sampling convenient and operation simple, effectively reducing analysis costs and shortening analysis time. There is almost no sample residue, and cleaning and reuse are very convenient.

[0027] 4. The ultrasonic atomization and flame-assisted thermal ionization method provided by this invention is compatible with common mass spectrometers (such as triple quadrupole mass spectrometers, time-of-flight mass spectrometers, ion trap mass spectrometers, Fourier transform ion cyclotron resonance mass spectrometers, etc.) and has a wide range of applications. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the device structure that enables the ultrasonic atomization and flame-assisted thermal ionization method provided by the present invention.

[0029] Figure 2 This is a diagram illustrating the relative positional relationship between the flame ignition end, the mass spectrometer sample introduction channel, and the ultrasonic sample introduction system in the ultrasonic atomization and flame-assisted thermal ionization method provided by this invention.

[0030] Figure 3 This is a mass spectrometry analysis chromatogram of glutathione obtained in Example 1 of the present invention;

[0031] Figure 4 This is the mass spectrometry analysis chromatogram of matrine obtained in Example 2 of the present invention;

[0032] Figure 5 This is the mass spectrometry analysis chromatogram of octadecyl alcohol obtained in Example 3 of the present invention;

[0033] Figure 6 This is the mass spectrometry analysis chromatogram of ferrocene obtained in Example 3 of the present invention;

[0034] Figure 7 This is a mass spectrometry analysis chromatogram of capsaicin (solvent: water) obtained in Example 4 of the present invention;

[0035] Figure 8 This is a mass spectrometry analysis chromatogram of capsaicin (solvent: methanol) obtained in Example 4 of the present invention;

[0036] Figure 9 This is a mass spectrometry analysis chromatogram of capsaicin (solvent: ethyl acetate) obtained in Example 4 of the present invention;

[0037] Figure 10 This is a mass spectrometry analysis chromatogram of capsaicin (solvent: petroleum ether) obtained in Example 4 of the present invention;

[0038] Figure 11 This is a standard curve of oxymatrine obtained in Example 5 of the present invention;

[0039] Figure 12 This is a mass spectrometry chromatogram of a test tube sample of the ethyl acetate:petroleum ether = 5:5 fraction obtained in Example 6 of the present invention;

[0040] Figure 13 This is a mass spectrometry chromatogram of a test tube sample of the ethyl acetate:petroleum ether = 6:4 fraction obtained in Example 6 of the present invention;

[0041] The following labels are used to indicate the components in the diagram: 1. Flame generating device; 11. Hydrogen generator; 12. Flame generating tube; 121. Flame ignition end; 13. Gas flow regulating valve; 2. Mass spectrometer injection channel; 3. Sample container; 4. Ultrasonic nebulizer; 41. Ultrasonic nebulizer; 42. Sound energy transfer medium; 5. Flame; 6. Sample solution; 7. Nebulized sample. Detailed Implementation

[0042] The technical solution of the present invention will be further described in detail and completely below with reference to the accompanying drawings.

[0043] Figure 1 and Figure 2 The diagram shows an apparatus for implementing the ultrasonic atomization and flame-assisted thermal ionization method provided by the present invention. It includes a flame generating device 1, a mass spectrometer injection channel 2, a sample container 3, and an ultrasonic atomizing device 4. The flame generating device 1 is used to generate a flame 5. The port of the mass spectrometer injection channel 2 is located in or near the flame 5 generated by the flame generating device 1. The port of the outlet end of the sample container 3 faces upward and is located below the port of the mass spectrometer injection channel 2. The ultrasonic atomizing device 4 is located at the bottom of the sample container 3.

[0044] The mass spectrometer used in this invention can be a common type of mass spectrometer, such as a triple quadrupole mass spectrometer, a time-of-flight mass spectrometer, an ion trap mass spectrometer, or a Fourier transform ion cyclotron resonance mass spectrometer.

[0045] The thermal ionization method of this invention, using the aforementioned apparatus, employs the port of the mass spectrometer injection channel 2, heated by the flame 5, as the ion source. The sample solution 6 in the sample container 3 is atomized using the ultrasonic nebulizer 4. The atomized sample 7 moves to the port of the mass spectrometer injection channel 2 and is ionized. The ionized sample ions enter the mass spectrometer through the mass spectrometer injection channel 2 for subsequent mass spectrometry analysis. Specifically, the method includes the following steps:

[0046] a) A flame 5 is generated by a flame generator 1, and the port of the mass spectrometer sample introduction channel 2 is heated by the flame 5;

[0047] b) Add the sample solution 6 to be tested to the sample container 3, and place the sample container 3 on the ultrasonic atomizing device 4;

[0048] c) Turn on the ultrasonic nebulizer 4. The ultrasonic nebulizer 4 atomizes the sample solution to be tested through the sample container 3. After the atomized sample 7 leaves the sample container 3, it moves to the port of the mass spectrometer injection channel 2 and is ionized.

[0049] In this invention, the flame generating device 1 is a hydrogen flame generating device, specifically comprising a hydrogen generator 11 and a flame generating tube 12 connected by a pipeline. The outlet end of the flame generating tube 12 is the flame ignition end 121, which is located near the port of the mass spectrometer sample introduction channel 2. Furthermore, a gas flow regulating valve 13 is provided on the pipeline connecting the hydrogen generator 11 and the flame generating tube 12 to regulate the gas flow rate, thereby regulating the size and temperature of the flame 5.

[0050] In this invention, the flame ignition end 121 is made of a high-temperature resistant material, such as stainless steel. Correspondingly, the flame generating tube 12 can be a high-temperature resistant needle tube.

[0051] In this invention, the port of the mass spectrometer injection channel 2 is an ion transmission tube, and the length H of the ion transmission tube is 5 to 10 mm, preferably 8 mm.

[0052] In this invention, the temperature of the port of the mass spectrometer injection channel 2 after being heated by flame is 300-800°C.

[0053] In this invention, the sample container 3 can be a commercially available product, as long as it can hold the sample and the outlet end faces upward, including but not limited to test tubes, liquid chromatography vials, and derivatization vials.

[0054] In this invention, the ultrasonic atomization device 4 includes an ultrasonic atomizer 41 and an acoustic energy transfer medium 42, wherein the acoustic energy transfer medium 42 is located between the ultrasonic atomizer 41 and the sample container 3. The ultrasonic atomizer 41 can be a commercially available product, as long as it can atomize the sample in the sample container 3 loaded on it, including but not limited to piezoelectric ceramic atomizing sheets (also known as ultrasonic atomizing transducers, ultrasonic atomizing oscillators, etc.). The diameter of the piezoelectric ceramic atomizing sheet affects the sample atomization efficiency; in this invention, a piezoelectric ceramic atomizing sheet with a diameter of 25 mm is selected. The acoustic energy transfer medium 42 includes, but is not limited to, ultrasonic coupling gel, to facilitate the ultrasonic atomizer 41 atomizing the sample through the sample container 3. In use, after applying an acoustic energy transmission medium 42 (e.g., ultrasonic coupling gel) to the bottom of the sample container 3, the sample container 3 is placed on an ultrasonic nebulizer 41 (e.g., a piezoelectric ceramic atomizing plate). The ultrasonic nebulizer 41 generates harmless high-frequency oscillations and transmits high-frequency mechanical waves through the sample container 3 to the liquid sample inside, causing cavitation and atomizing the sample. After a single sample is analyzed, the sample container 3 is removed, and the acoustic energy transmission medium 42 at the bottom of the sample container 3 is wiped with paper. The next sample can then be analyzed, making the process very convenient and quick. The ultrasonic nebulization device 4 is simple in structure, easy to operate, produces no noise pollution, and consumes very little sample per analysis.

[0055] In this invention, the mass spectrometer injection channel 2 is separated from the flame ignition end 121 and the ultrasonic nebulizer 4, and the relative positions of the three are adjustable. Specifically, the ultrasonic nebulizer 4 and the sample container 3 are located below the port of the mass spectrometer injection channel 2 (preferably directly below), and the outlet port of the sample container 3 faces upward (preferably directly opposite the port of the mass spectrometer injection channel 2). After the sample in the sample container 3 is atomized by the ultrasonic nebulizer 4, it forms small sample droplets that move upward from the outlet port of the sample container 3 and are ionized at the port of the mass spectrometer injection channel 2.

[0056] like Figure 2 As shown, in this invention, the distance H between the port of the mass spectrometer sample introduction channel 2 and the ultrasonic nebulizer 4 is 2 to 15 cm, and this distance can be adjusted according to the size of the sample container 3 used.

[0057] like Figure 2 As shown, in this invention, the axis of the mass spectrometer injection channel 2 and the axis of the flame generator tube 12 are on the same horizontal plane and the included angle is 90°.

[0058] like Figure 2 As shown, in this invention, the distance D between the port of the mass spectrometer injection channel 2 and the flame ignition end 121 is 2 to 13 millimeters.

[0059] The technical effects achievable by the present invention will be further illustrated below with reference to specific application examples.

[0060] Example 1

[0061] The above-described apparatus, along with a mass spectrometer (triple quadrupole mass analyzer) and the thermal ionization method described in this invention, were used to analyze the polypeptide compound glutathione. Perform mass spectrometry analysis:

[0062] Glutathione standard was dissolved in deionized water to prepare a 50 μg / mL sample solution for later use. A flame 5 was generated by flame generator 1 and used to heat the port of mass spectrometry injection channel 2. 200 μL of sample solution was added to sample container 3 (derivative vial). Sample container 3 was placed on ultrasonic nebulizer 41 (piezoelectric ceramic nebulizer) coated with acoustic energy transfer medium 42 (ultrasonic coupling gel). Ultrasonic nebulizer 41 was turned on, and ultrasonic nebulizer 4 atomized the sample solution through sample container 3. The liquid in sample container 3 was atomized and entered the port of mass spectrometry injection channel 2 for ionization. The ionized sample entered the mass spectrometer through mass spectrometry injection channel 2 for data acquisition and analysis.

[0063] Figure 3 This is the mass spectrum of the glutathione obtained in this embodiment, from... Figure 3As can be seen, the spectrum contains a high-intensity [M+H] group of glutathione. + Signals: m / z 308 and [M+K] + The signal is m / z 346, and there are few other interfering peaks, indicating that the present invention has a good detection capability for small molecule peptides.

[0064] Example 2

[0065] The above-described apparatus, along with a mass spectrometer (triple quadrupole mass analyzer) and the thermal ionization method described in this invention, were used to analyze the alkaloid compound matrine. Perform mass spectrometry analysis:

[0066] Matrine standard was dissolved in a mixed solvent (V) H2O :V MeOH Prepare a 50 μg / mL sample solution using a ratio of 6:4; generate a flame 5 using a flame generator 1 to heat the port of the mass spectrometer injection channel 2; add 200 μL of the sample solution to the sample container 3 (derivative vial); place the sample container 3 on an ultrasonic nebulizer 41 (piezoelectric ceramic nebulizer) coated with an acoustic energy transfer medium 42 (ultrasonic coupling gel); turn on the ultrasonic nebulizer 41; the ultrasonic nebulizer 4 atomizes the sample solution through the sample container 3; the liquid in the sample container 3 is atomized and enters the port of the mass spectrometer injection channel 2 to be ionized; the ionized sample enters the mass spectrometer through the mass spectrometer injection channel 2 for data acquisition and analysis.

[0067] Figure 4 This is the mass spectrum of matrine obtained in this embodiment, from... Figure 4 As can be seen, the spectrum contains [M+H] of matrine with relatively high potency. + Signals: m / z 249 and [M+K] + The signal is m / z 287, and there are few other interfering peaks, indicating that the present invention has a good detection capability for alkaloids.

[0068] Example 3

[0069] The above-described apparatus, along with a mass spectrometer (triple quadrupole mass analyzer) and the thermal ionization method described in this invention, are used to analyze the low-polarity compound ferrocene. and octadecanol Perform mass spectrometry analysis:

[0070] Octadecyl alcohol standard was dissolved in 95% ethanol, and ferrocene standard was dissolved in petroleum ether to prepare sample solutions of 0.5 mg / mL for later use. A flame 5 was generated by flame generator 1 and heated the port of mass spectrometer injection channel 2 by flame 5. 200 μL of sample solution was added to sample container 3 (derivative vial). Sample container 3 was placed on ultrasonic nebulizer 41 (piezoelectric ceramic nebulizer) coated with acoustic energy transfer medium 42 (ultrasonic coupling gel). Ultrasonic nebulizer 41 was turned on, and ultrasonic nebulizer 4 nebulized the sample solution to be tested through sample container 3. After being nebulized, the liquid in sample container 3 entered the port of mass spectrometer injection channel 2 and was ionized. The ionized sample entered the mass spectrometer through mass spectrometer injection channel 2 for data acquisition and analysis.

[0071] Figure 5 This is the mass spectrum of octadecyl alcohol obtained in this embodiment, from... Figure 5 As can be seen, the spectrum shows a relatively strong [M+C2H5OH+K] group of octadecyl alcohol. + Signals: m / z 355 and the second strongest [M+C2H5OH+Na] + Signal: m / z 339.

[0072] Figure 6 The mass spectrum of ferrocene obtained in this embodiment is shown below. Figure 6 As can be seen, a high-intensity molecular ion peak signal of ferrocene appeared in the spectrum: m / z 186;

[0073] Depend on Figure 5 and Figure 6 The results show that the present invention also has a high ionization efficiency for low polarity compounds, which is difficult to achieve with conventional ESI technology.

[0074] Example 4

[0075] The above-described apparatus, along with a mass spectrometer (triple quadrupole mass analyzer) and the thermal ionization method described in this invention, was used to analyze capsaicin in four solvents with different polarities (water, methanol, ethyl acetate, and petroleum ether). Perform mass spectrometry analysis:

[0076] Capsaicin standards were dissolved in water, methanol, ethyl acetate, and petroleum ether to prepare sample solutions of 50 μg / mL. A flame 5 was generated using flame generator 1, which heated the port of mass spectrometry injection channel 2. 200 μL of the sample solution was added to sample container 3 (derivatization vial). Sample container 3 was placed on an ultrasonic nebulizer 41 (piezoelectric ceramic nebulizer plate) coated with acoustic energy transfer medium 42 (ultrasonic coupling gel). The ultrasonic nebulizer 41 was turned on, and the ultrasonic nebulizer 4 atomized the sample solution through sample container 3. The atomized liquid in sample container 3 entered the port of mass spectrometry injection channel 2 and was ionized. The ionized sample entered the mass spectrometer through mass spectrometry injection channel 2 for data acquisition and analysis. The analysis results are as follows: Figures 7-10 As shown.

[0077] Figure 7 This is the mass spectrum of capsaicin (in water) obtained in this embodiment; Figure 8 This is the mass spectrum of capsaicin (in methanol) obtained in this embodiment; Figure 9 This is the mass spectrum of capsaicin (solvent: ethyl acetate) obtained in this example; Figure 10 This is the mass spectrum of capsaicin (solvent: petroleum ether) obtained in this embodiment. Figures 7 to 10 As can be seen, the above spectra all show capsaicin [M+K] with the highest signal intensity. + The peak, and the second most intense [M+Na] peak. + Peaks and [M+H] + The peak indicates that the present invention is compatible with a variety of solvents with different polarities, and also has high ionization efficiency for low polarity solvents, showing good versatility.

[0078] Example 5

[0079] Feasibility study of the ultrasonic atomization and flame-assisted thermoionization method described in this invention for quantitative analysis:

[0080] Using oxymatrine as the research object, oxymatrine was dissolved in a mixed solvent (V H2O :V MeOHIn a 6:4 ratio, oxymatrine standard solutions with concentrations of 5 ng / mL, 10 ng / mL, 20 ng / mL, 50 ng / mL, 100 ng / mL, 200 ng / mL, and 500 ng / mL were prepared for later use. A flame 5 was generated using flame generator 1, and the port of mass spectrometry injection channel 2 was heated by flame 5. 200 μL of sample solution was added to sample container 3 (derivatization vial). Sample container 3 was placed on an ultrasonic nebulizer 41 (piezoelectric ceramic nebulizer plate) coated with acoustic energy transfer medium 42 (ultrasonic coupling gel). The ultrasonic nebulizer 41 was turned on, and the ultrasonic nebulizer 4 atomized the sample solution through sample container 3. The liquid in sample container 3 was atomized and then entered the port of mass spectrometry injection channel 2 for ionization. The ionized sample entered the mass spectrometer through mass spectrometry injection channel 2 for data acquisition and analysis. A standard curve was plotted with concentration as the x-axis and average peak area as the y-axis. The results are shown below. Figure 11 As shown.

[0081] Figure 11 The figure shows the standard curve of oxymatrine obtained in this embodiment. As can be seen from the figure, the linear relationship is good in the concentration range of 5 ng / mL to 500 ng / mL, indicating that the present invention has the potential for accurate quantitative analysis.

[0082] Example 6

[0083] The silica gel column chromatography separation products of tangerine peel extract were analyzed by mass spectrometry using the above-mentioned apparatus, a mass spectrometer (triple quadrupole mass analyzer), and the thermal ionization method described in this invention.

[0084] The tangerine peel alcohol extract was extracted with n-hexane and then with dichloromethane to obtain the dichloromethane extract. The product was separated by silica gel column chromatography. The eluent was ethyl acetate:petroleum ether solution with volume ratios of 0:10, 2:8, 4:6, 5:5, and 6:4. The eluent was collected in test tubes, with each test tube containing approximately 18 mL of eluent. The test tube was also used as the sample container 3 for analysis.

[0085] A flame 5 is generated by a flame generator 1, which heats the port of the mass spectrometer sample inlet channel 2. The sample container 3 is placed on an ultrasonic nebulizer 41 (piezoelectric ceramic nebulizer) coated with an acoustic energy transfer medium 42 (ultrasonic coupling gel). The ultrasonic nebulizer 41 is turned on, and the ultrasonic nebulizer 4 atomizes the sample solution to be tested through the sample container 3. After being atomized, the liquid in the sample container 3 enters the port of the mass spectrometer sample inlet channel 2 and is ionized. The ionized sample enters the mass spectrometer through the mass spectrometer sample inlet channel 2 for data acquisition and analysis.

[0086] Figure 12 This is a mass spectrum of a test tube sample in a 5:5 fraction of ethyl acetate:petroleum ether. Figure 12As can be seen in the image: hesperidin [M+H] is present. + The signal m / z is 373; Figure 13 This is a mass spectrum of a test tube sample containing ethyl acetate:petroleum ether in a 6:4 ratio. Figure 13 As can be seen in the image: Noriheptacortin [M+H] is present. + The signal m / z is 403; this indicates that the present invention can be used to perform rapid qualitative analysis on large-volume samples without additional processing, which can significantly save analysis costs and time.

[0087] In summary, the ultrasonic nebulization and flame-assisted thermal ionization method provided by this invention does not use the flame 5 as the ion source, but rather the port of the mass spectrometry sample introduction channel 2 heated by the flame 5. The flame 5 does not directly contact the sample; instead, the port of the mass spectrometry sample introduction channel 2 uses the heat provided by the flame 5 to ionize the sample. This is a relatively "soft" ionization method, which can effectively reduce thermal decomposition, provide a stable and sensitive mass spectrometry signal, and has no strict limitations on the polarity of the sample or the type of solvent. It also has high ionization efficiency for low-polarity compounds and low-polarity solvents, and has good versatility. In addition, by using the ultrasonic nebulization device 4 as the sample introduction method, the limitation on sample volume can be effectively reduced, and the experimental operation can be simplified, greatly reducing the analysis time and economic cost. Furthermore, the sample is not placed directly on the ultrasonic nebulization device 4 for ultrasonic nebulization, but is placed in the sample container 3 and then placed on the ultrasonic nebulization device 4. The ultrasonic nebulization device 4 nebulizes the sample through the sample container 3, which can effectively reduce cross-contamination and improve analytical throughput.

[0088] Finally, it should be pointed out that the above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for ultrasonic atomization and flame-assisted thermal ionization, characterized in that: The method uses the port of the mass spectrometer injection channel, which is heated by a flame, as the ion source, and uses an ultrasonic nebulizer to atomize the sample solution in the sample container. The atomized sample then moves to the port of the mass spectrometer injection channel and is ionized. The method includes the following steps: a) Generate a flame using a flame generator and position the port of the mass spectrometer injection channel in or near the flame generated by the flame generator, and heat the port of the mass spectrometer injection channel to a temperature of 300–800°C using the flame. b) Add the sample solution to be tested into the sample container, with the outlet end of the sample container facing upward and below the port of the mass spectrometer injection channel, and place the sample container on the ultrasonic nebulizer. c) Turn on the ultrasonic nebulizer. The ultrasonic nebulizer atomizes the sample solution to be tested through the sample container. After the atomized sample leaves the sample container, it moves to the port of the mass spectrometer injection channel and is ionized.

2. The thermal ionization method according to claim 1, characterized in that: The flame generating device includes a hydrogen generator and a flame generating tube connected by a pipeline. The outlet end of the flame generating tube is the flame ignition end, which is located near the port of the mass spectrometer sample introduction channel.

3. The thermal ionization method according to claim 2, characterized in that: A gas flow regulating valve is installed on the pipeline connecting the hydrogen generator and the flame generating tube.

4. The thermal ionization method according to claim 2, characterized in that: The distance between the port of the mass spectrometer injection channel and the flame ignition end is 2-13 mm.

5. The thermal ionization method according to claim 1, characterized in that: The ultrasonic atomization device includes an ultrasonic atomizer and an acoustic energy transfer medium, wherein the acoustic energy transfer medium is located between the ultrasonic atomizer and the sample container.

6. The thermal ionization method according to claim 5, characterized in that: The ultrasonic atomizer is a piezoelectric ceramic atomizing sheet, and the acoustic energy transmission medium is an ultrasonic coupling gel.

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