Coaxial nanoelectrospray atmospheric pressure chemical ionization composite ionization source for ionization

Abstract

The present invention relates to the technical field of mass spectrometry analysis, and in particular to a coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization. The source comprises a drawn glass capillary, an insulating dielectric tube, an inner electrode, an outer electrode, a non-contact electrode, a high-voltage AC power supply, and a high-voltage pulse power supply. The insulating dielectric tube and the drawn glass capillary are coaxially arranged, the front end of the drawn glass capillary extends out of the insulating dielectric tube, the inner electrode and the outer electrode are coated on the outer walls of the drawn glass capillary and the insulating dielectric tube, and are connected to the high-voltage AC power supply. The non-contact electrode is placed below the tip of the drawn glass capillary and is connected to the high-voltage pulse power supply. A discharge gas is introduced into the insulating dielectric tube, and the high-voltage pulse power supply and the high-voltage AC power supply are turned on to realize nano-electrospray ionization and atmospheric pressure chemical ionization ionization modes. The present invention realizes efficient ionization of liquid samples and cell samples, and realizes multi-component online analysis of liquid and cell samples by combining with mass spectrometry.

Description

Technical Field

[0001] The present invention relates to the technical field of mass spectrometry analysis, in particular to a coaxial nanoliter electrospray atmospheric pressure chemical ionization composite ionization source for ionization. Background Art

[0002] Cellular heterogeneity is inherent due to the stochastic regulation of gene expression and microenvironmental perturbations during biological processes. Elucidating cellular heterogeneity cannot be achieved through population-level measurements, as the overall study of large samples obscures true individual variability. Therefore, revealing cellular heterogeneity at the single-cell level is extremely valuable for truly reflecting the role of individual cells in physiological processes and providing new insights into rare cell types such as circulating tumor cells, cancer stem cells, and primary cells.

[0003] Single-cell metabolomics has garnered significant attention in recent years due to its ability to provide transient and dynamic phenotypic information. Due to the inherent characteristics of single cells, such as picoliter-scale cell volumes, rapid biochemical reaction rates, complex metabolite profiles with low abundance, and a lack of amplification technology, single-cell metabolomics is more challenging than single-cell genomics, transcriptomics, and proteomics. Mass spectrometry, with its superior sensitivity, resolution, and rapid response, has ushered in a new era in single-cell metabolomics.

[0004] A variety of mass spectrometry ionization methods have been developed that can ionize different types of samples. Among them, nanoelectrospray ionization (nanoESI) is an atmospheric pressure open ion source that is suitable for rapid detection of single-cell samples. It has also spawned a series of related technologies, including induced nanoESI (InESI), pulsed direct current electrospray ionization mass spectrometry (pulsed-dc-ESI-MS), nanoESI based on electromigration and electroporation, single probes, T probes, and high-throughput single-cell technologies that combine inkjet printing, spiral capillaries, flow cytometry, and microfluidic chips. These ionization methods have shown the characteristics of high sensitivity, low detection limits, and high throughput, but are limited by the ionization mechanism of nanoESI, and the metabolites detected are limited to highly abundant and easily ionized polar metabolites. The detection of low-abundance, low-ionization-efficiency, and weakly polar metabolites in cells places higher demands on achieving high-coverage single-cell metabolomics.

[0005] Ionization methods with different mechanisms complement each other, providing complementary information about sample composition and expanding the scope of single-cell metabolite detection. Atmospheric pressure chemical ionization (APCI), a plasma-based, open-air soft ionization method at ambient pressure, offers unique advantages in ionizing weakly polar compounds and is highly complementary to nanoESI. Therefore, developing a composite ionization source that combines two distinct ionization modes is crucial for achieving high-coverage, comprehensive analysis of single-cell metabolomics. Summary of the Invention

[0006] In response to the above problems, the purpose of the present invention is to provide a coaxial nanoelectrospray atmospheric pressure chemical ionization composite ionization source for ionization, so as to achieve efficient ionization of liquid samples and cell samples, and realize multi-component online analysis of liquid and cell samples by combining with mass spectrometry.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization, comprising a drawn glass capillary, an insulating dielectric tube, an inner electrode, an outer electrode, a non-contact electrode, a high-voltage AC power supply and a high-voltage pulse power supply, wherein the insulating dielectric tube is coaxially sleeved on the outside of the drawn glass capillary, the front end of the drawn glass capillary is pointed and extends out of the insulating dielectric tube, and the drawn glass capillary is used to hold samples; the inner electrode and the outer electrode are respectively coated on the outer walls of the drawn glass capillary and the insulating dielectric tube, and the non-contact electrode is placed below the tip of the drawn glass capillary; the inner electrode and the outer electrode are connected to the high-voltage AC power supply; the non-contact electrode is connected to the high-voltage pulse power supply; the high-voltage pulse power supply is turned on to realize the nano-electrospray ionization mode; discharge gas is introduced into the insulating dielectric tube, and the high-voltage pulse power supply and the high-voltage AC power supply are turned on at the same time to realize the nano-electrospray ionization and atmospheric pressure chemical ionization ionization modes.

[0009] The insulating medium tube is a straight hollow tube, and the rear end of the insulating medium tube is connected to the gas storage device through a discharge gas injection tube.

[0010] The insulating medium tube is made of glass, quartz or ceramic; the length of the insulating medium tube is 20-100 mm and the inner diameter is 3-6 mm.

[0011] The drawn glass capillary is made of glass; the length of the drawn glass capillary is 10-20 mm, and the diameter of the tip is 1-20 μm; the length of the drawn glass capillary extending from the insulating medium tube is 5-20 mm; the tip of the drawn glass capillary is coaxial with the mass spectrometry injection cone, and the distance between the tip and the mass spectrometry injection cone is 5-20 mm.

[0012] The inner electrode and the outer electrode are both ring-shaped electrodes, and both the inner electrode and the outer electrode are copper foils.

[0013] The length of the inner electrode is 5-15 mm; the length of the outer electrode is 10-90 mm.

[0014] The non-contact electrode is a sheet electrode, and the non-contact electrode is a copper foil, and is placed 1-10 mm below the tip of the drawn glass capillary.

[0015] The voltage of the high-voltage AC power supply is 1-10 kV, the frequency is 0.5-50 kHz, and the power is 1-60 W; the voltage of the high-voltage pulse power supply is 1-10 kV, the frequency is 0.1-10 kHz, and the power is 1-60 W.

[0016] The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization also includes a position adjustment device and a connecting component, wherein the connecting component is used to fix the insulating medium tube, the position adjustment device is connected to the connecting component, and the position adjustment device is used to adjust the spatial position of the composite ionization source.

[0017] The discharge gas is one of nitrogen, helium, argon, air and carbon dioxide or any mixture thereof; the flow rate of the discharge gas is 0.01-1.0 L / min; and the sample is a liquid sample or a cell sample.

[0018] The advantages and beneficial effects of the present invention are:

[0019] 1. The composite ionization source of the present invention, with its coaxially nested structure of a nanoelectrospray ion source and an atmospheric pressure chemical ionization ion source, and the rational selection of the types and flow rates of auxiliary solvents and discharge gases, can achieve efficient ionization of liquid and cell samples. By combining with mass spectrometry, it can realize multi-component online analysis of liquid and cell samples.

[0020] 2. A large amount of active species N2 in the APCI plasma plume +· ,N4 +· ,N2 * and H3O + It can react with compounds to form radical cations or protonated ions through charge transfer, electron impact, Penning ionization, and proton transfer, and has unique advantages in the ionization of weakly polar compounds. The non-contact electrode induces the release of charged droplets from the tip of the drawn glass capillary, forming a nanoESI plume, which facilitates the ionization of polar compounds. The APCI-plasma plume and the nanoESI plume converge at the tip of the drawn glass capillary, allowing samples to be ionized simultaneously by nanoESI and APCI, achieving higher ionization efficiency and analytical sensitivity. This allows for the detection of highly abundant and easily ionized polar compounds in the sample, as well as for the mining of information about low-abundance, low-ionization-efficiency, and weakly polar compounds in the sample, providing a richer, more comprehensive picture of the sample, with the advantages of high coverage, high sensitivity, and rich information.

[0021] 3. This coaxial nanoESI-APCI composite ionization source is assembled and processed from readily available commercial parts, eliminating the need for delicate machining or complex mass spectrometer modifications. The high-voltage power supply used in this device is low-power, minimizing the risk of hazard. The sample ionization process is simple, overcoming APCI's reliance on a corona needle, eliminating the need for DART's carrier gas heating device, and overcoming DESI's reliance on solvents. The ionized sample enters the mass spectrometer directly for detection under the combined effects of the vacuum negative pressure and discharge gas impact within the mass spectrometer inlet. This device offers advantages such as miniaturization, integration, simple structure, ease of processing, and convenient operation.

[0022] 4. The composite ionization source of the present invention requires no complex sample pretreatment and has a wide range of applications. It can directly analyze liquid samples, fresh tissues digested into suspended cells, or rare cells such as circulating tumor cells, tumor stem cells, and primary cells. It can serve as an effective tool for studying cancer therapy, drug screening, cellular heterogeneity, cell-cell interactions, and rare cell types. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to the present invention;

[0024] Figure 2 Schematic diagram of the structure of the APCI ionization source in the present invention;

[0025] Figure 3 Schematic diagram of the structure of the nanoESI ionization source in the present invention;

[0026] Figure 4 Schematic diagram of the structure of the position adjustment device in the present invention;

[0027] Figure 5 The metabolome of a single MCF7 cell was analyzed using the coaxial nanoESI-APCI composite ionization source in positive ion mode in Example 1 of the present invention: (A) total ion current chromatograms in nanoESI mode and nanoESI-APCI mode, (B) extracted ion chromatogram of phosphocholine (m / z 184.0733), (C) extracted ion chromatogram of creatine (m / z 132.0768), (D) mass spectrum with APCI off, and (E) mass spectrum with APCI on.

[0028] Figure 6 This is the high-dimensional data dimensionality reduction and visualization (t-SNE) analysis of the metabolic profiles of three types of cancer cells in the positive ion mode in Example 2 of the present invention;

[0029] Figure 7 This is the t-SNE analysis of the metabolic profiles of two prostate cancer subtypes in the positive ion mode in Example 3 of the present invention;

[0030] Figure 8 t-SNE analysis of the metabolic profiles of cancer stem cells and non-cancer stem cells under positive ion mode in Example 4 of the present invention;

[0031] Figure 9 The intensity comparison of 9 model compounds in nanoESI mode and nanoESI-APCI mode in Example 5 of the present invention is shown.

[0032] In the figure: 1- drawn glass capillary, 2- insulating dielectric tube, 3- inner electrode, 4- outer electrode, 5- contactless electrode, 6- connecting assembly, 7- high voltage AC power supply, 8- high voltage pulse power supply, 9- position adjustment device, 10- mass spectrometer injection cone, 11- APCI plasma plume, 12- nanoESI plume. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to specific embodiments: The embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are given, but the protection scope of the present invention is not limited to the following embodiments.

[0034] Example 1

[0035] like Figure 1 As shown, the present invention provides a coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization, comprising a drawn glass capillary 1, an insulating dielectric tube 2, an inner electrode 3, an outer electrode 4, a non-contact electrode 5, a high-voltage AC power supply 7 and a high-voltage pulse power supply 8, wherein the insulating dielectric tube 2 is coaxially sleeved on the outside of the drawn glass capillary 1, the front end of the drawn glass capillary 1 is pointed and extends out of the insulating dielectric tube 2, and the drawn glass capillary 1 is used to hold samples; the inner electrode 3 and the outer electrode 4 are respectively coated on the outer walls of the drawn glass capillary 1 and the insulating dielectric tube 2, and the non-contact electrode 5 is placed under the tip of the drawn glass capillary 1; the inner electrode 3 and the outer electrode 4 are connected to the high-voltage AC power supply 7; the non-contact electrode 5 is connected to the high-voltage pulse power supply 8; the high-voltage pulse power supply 8 is turned on to realize the nano-electrospray ionization mode; the discharge gas is introduced into the insulating dielectric tube 2, and the high-voltage pulse power supply 8 and the high-voltage AC power supply 7 are turned on at the same time to realize the nano-electrospray ionization and atmospheric pressure chemical ionization ionization modes.

[0036] See also Figure 2 As shown, in the embodiment of the present invention, the insulating medium tube 2 is a straight hollow tube, and the rear end of the insulating medium tube 2 is connected to the gas storage device through a discharge gas injection tube.

[0037] In this embodiment, the insulating medium tube 2 is made of glass, quartz or ceramic; the length of the insulating medium tube 2 is adjustable, generally not less than 20 mm, specifically 20-100 mm. In order to ensure that the discharge electric field intensity is sufficiently large, the inner diameter of the insulating medium tube should generally be less than 6 mm, specifically 3-6 mm.

[0038] In this embodiment, the drawn glass capillary 1 is made of glass. The length of the drawn glass capillary 1 is adjustable, generally not less than 10 mm, and specifically can be 10-20 mm. The diameter of the tip is adjustable, generally less than 20 μm, and specifically can be 1-20 μm. The length of the drawn glass capillary 1 extending from the insulating medium tube 2 is adjustable, generally less than 20 mm, and specifically can be 5-20 mm. The tip of the drawn glass capillary 1 is coaxial with the mass spectrometer injection cone 10, and the distance between the tip and the mass spectrometer injection cone 10 is 5-20 mm.

[0039] In an embodiment of the present invention, both the inner electrode 3 and the outer electrode 4 are annular electrodes and are copper foil. The length of the inner electrode 3 is adjustable, specifically 5-15 mm; the length of the outer electrode 4 is adjustable, specifically 10-90 mm. The APCI plasma is distributed between the insulating dielectric tube 2 and the inner electrode 3, and in the space corresponding to the outer electrode 4. After the discharge gas enters the insulating dielectric tube 2, it discharges to generate an APCI plasma plume 11, which is ejected from the outlet of the insulating dielectric tube 2. In this embodiment, the high-voltage AC power supply 7 has a voltage of 1-10 kV, a frequency of 0.5-50 kHz, and a power of 1-60 W.

[0040] See also Figure 3 As shown, in an embodiment of the present invention, non-contact electrode 5 is a sheet electrode, made of copper foil, and is placed 1-10 mm below the tip of the drawn glass capillary 1. In this embodiment, high-voltage pulse power supply 8 has a voltage of 1-10 kV, a frequency of 0.1-10 kHz, and a power of 1-60 W. Non-contact electrode 5 induces the tip of the drawn glass capillary 1 to release charged droplets, forming a nanoESI plume 12.

[0041] See also Figure 4 As shown, based on the above embodiment, the coaxial nanoelectrospray atmospheric pressure chemical ionization composite ionization source for ionization provided by the present invention also includes a position adjustment device 9 and a connecting component 6, wherein the connecting component 6 is used to fix the insulating medium tube 2, the position adjustment device 9 is connected to the connecting component 6, and the position adjustment device 9 is used to adjust the spatial position of the composite ionization source.

[0042] In this embodiment, the discharge gas is one of nitrogen, helium, argon, air and carbon dioxide or any mixture thereof; the flow rate of the discharge gas is 0.01-1.0 L / min; and the sample is a liquid sample or a cell sample.

[0043] The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization provided by the present invention has the following working principle:

[0044] A sample, either a liquid or cell sample, is added to a drawn glass capillary 1. The capillary 1 is coaxially nested within an insulating dielectric tube 2, with the distal end extending 5-20 mm beyond the tube. Discharge gas is introduced to fill the tube 2. High-voltage AC power supply 7 and high-voltage pulse power supply 8 are then turned on to simultaneously subject the sample to nanoelectrospray ionization and atmospheric pressure chemical ionization.

[0045] Specifically, there are two methods for adding a sample to the drawn glass capillary 1: method a and method b.

[0046] Method a involves adding 0.5-20 μL of liquid sample to the rear end of a drawn glass capillary 1 and is suitable for liquid samples. Method b involves injecting 0.5-20 μL of an auxiliary solvent into the rear end of a drawn glass capillary 1. The drawn glass capillary 1 is then secured to a sliding rail connected to a three-dimensional micro-motion platform. Using a microscope, the tip of the drawn glass capillary 1 is precisely inserted into a cell. Aspiration is performed under negative pressure for 60-120 seconds and is suitable for cell samples. The discharge gas is selected from nitrogen, helium, argon, air, carbon dioxide, or any combination thereof, with a gas flow rate of 0.01-1.0 L / min. When ionization is performed using a coaxial nanoESI-APCI composite ionization source, the discharge gas inlet line can be equipped with a flowmeter for measuring the gas flow rate and a flow valve for controlling the gas flow rate. Specifically, the auxiliary solvent is a volatile solvent or a mixture of a volatile solvent and water. The volatile solvent is selected from at least one of methanol, acetonitrile, isopropanol, and chlorobenzene. When the high-voltage pulse power supply 8 is turned on, only nanoelectrospray ionization can be achieved, that is, nanoESI mode; when the high-voltage pulse power supply and the high-voltage AC power supply are turned on at the same time, nanoelectrospray ionization and atmospheric pressure chemical ionization can be achieved at the same time, that is, nanoESI-APCI mode.

[0047] All mass spectrometry measurements were performed on an Orbitrap Q Exactive-HF MS (Thermo Fisher Scientific, San Jose, CA, USA). The instrument operating parameters were as follows:

[0048] Capillary temperature: 275°C;

[0049] MS1 resolution: 60,000;

[0050] Mass range: 70-1050 m / z;

[0051] S-Lens RF level: 50;

[0052] Micro scan: 1;

[0053] Automatic gain control (AGC target): 1e 5 ;

[0054] Maximum injection time: 100ms.

[0055] Before the experiment, the commercial ESI ion source of the Q Exactive-HF MS must be removed and connected to this device as an external mass spectrometry interface.

[0056] First, prepare the cells as follows: remove the culture medium, rinse the MCF7 cells three times with PBS to remove the culture medium that interferes with data acquisition, add PBS to the culture dish, and place the culture dish under the inverted microscope stage to pierce the target cells and monitor the sampling process.

[0057] 0.5-20 μL of auxiliary solvent, a mixture of methanol and water, was injected into the rear end of the drawn glass capillary 1. The capillary was fixed on a movable slide connected to a three-dimensional micro-motion operation platform. The needle tip was precisely inserted into the cell with the help of a microscope. The capillary was aspirated under negative pressure for 60-120 seconds. The drawn glass capillary 1 was then coaxially inserted into the insulating dielectric tube 2 to construct a coaxial nanoESI-APCI composite ionization source.

[0058] The metabolome of single MCF7 cells was analyzed in positive ion mode using the above conditions. Figure 5 A in the figure is the total ion current chromatogram (TIC), Figure 5 B in the figure is the extracted ion chromatogram (EIC) of phosphorylcholine (m / z 184.0733). Figure 5 C in the equation is the EIC of creatine (m / z 132.0768). Figure 5 D in the figure is the metabolic fingerprint of a single cell in nanoESI mode. Figure 5 The E in the figure represents the metabolic fingerprint of a single cell in nanoESI-APCI mode. These results demonstrate that nanoESI-APCI mode can yield richer spectral information and that the coaxial nanoESI-APCI composite ionization source is capable of single-cell metabolome analysis.

[0059] Example 2

[0060] The ion source and method used were the same as in Example 1. 20-50 MCF7, 97H and PC3 cells were respectively picked and t-SNE analysis was performed on the metabolic fingerprints in the positive ion mode. Figure 6It shows that the single-cell metabolic profile obtained by this coaxial nanoESI-APCI composite ionization source can be used to distinguish different cancer cell types.

[0061] Example 3

[0062] The ion source and method used were the same as in Example 1. 20-50 PC3 and DU145 cells were respectively pierced and t-SNE analysis was performed on the metabolic fingerprints in the positive ion mode. Figure 7 It was shown that the single-cell metabolic profile obtained by the coaxial nanoESI-APCI composite ionization source can be used to distinguish different cancer cell subclasses, demonstrating the practicality and universality of this device for cell type identification.

[0063] Example 4

[0064] Preparation of cancer stem cells (CSCs) and non-cancer stem cells (NSCCs) was performed as follows: CWR-22Rv1 cells were cultured in serum-free spheroid medium in ultra-low adhesion 6-well plates. Stem cells proliferated to form suspended spheroids. The spheroid culture medium consisted of DMEM / F12 (1:1), 20 ng / mL bFGF, 20 μL / mL B27, and 20 ng / mL EGF. After 7-10 days of stem cell culture, the spheroids were collected by filtration through a 100 μm cell sieve and digested with 1 mL of Accutase in a 37°C water bath for 10 minutes. Digestion was then terminated by adding 2 mL of spheroid medium. The cells were collected into a centrifuge tube and centrifuged at 100 g for 2 minutes. The cells were washed twice with PBS and resuspended in PBS for single-cell sampling and analysis. For control studies, CWR-22Rv1 cells cultured in DMEM / F12 (1:1) medium containing 10% FBS were used as an NSCC model. The medium was removed, and the cells were rinsed three times with PBS to remove the medium that interfered with data acquisition. PBS was added to the culture dish, and the dish was placed under an inverted microscope stage to pierce the target cells and monitor the sampling process.

[0065] The ion source and method used were the same as those in Example 1. 20-50 CSC and NSCC cells were respectively picked and t-SNE analysis was performed on the metabolic fingerprints in the positive ion mode. Figure 8 The results showed that there were significant differences in the single-cell metabolic profiles of CSCs and NSCCs, proving that this device can be used for metabolomics research on rare cells such as cancer stem cells, circulating tumor cells, and primary cells.

[0066] Example 5

[0067] Nine representative model compounds of different polarities were selected for mass spectrometry analysis, namely: histidine, fumaric acid, chenodeoxycholic acid (CDCA), guanosine, octan-3-one, corticosterone, fatty acid (FA) 14:0, phosphatidylethanolamine (PE) 16:0 / 18:1, and carbazole.

[0068] The ion source and method used were the same as those in Example 1. The nine model compounds were dissolved in a methanol-water solution to prepare a 10 μg / mL mixed standard solution. 0.5-20 μL of the mixed standard sample was added to the rear end of a drawn glass capillary 1, which was then coaxially inserted into an insulating dielectric tube 2 to construct a coaxial nanoESI-APCI composite ionization source.

[0069] Figure 9 Shown is a comparison of the intensities of the nine model compounds described above in positive ion mode using nanoESI and nanoESI-APCI modes. For both polar and weakly polar compounds, the nanoESI-APCI hybrid mode improves product ion response, demonstrating that the coaxial nanoESI-APCI hybrid ionization source achieves higher ionization efficiency than a single nanoESI ionization source.

[0070] In embodiments of the present invention, a coaxially nested nanoelectrospray ionization source and an atmospheric pressure chemical ionization ionization source are employed, along with appropriate selection of auxiliary solvent and discharge gas types and flow rates, to achieve efficient ionization of liquid and cell samples. Combined with mass spectrometry, this composite ionization source enables multi-component online analysis of liquid and cell samples. The composite ionization source of the present invention eliminates the need for complex sample pretreatment and has a wide range of applications. It can directly analyze liquid samples, fresh tissues digested into suspended cells, or rare cells such as circulating tumor cells, tumor stem cells, and primary cells. It can serve as an effective tool for studying cancer therapy, drug screening, cellular heterogeneity, cell-cell interactions, and rare cell types.

[0071] In summary, the present invention provides a coaxial nanoelectrospray (nanoESI)-atmospheric pressure chemical ionization (APCI) composite ionization source for cell ionization, which utilizes the coaxial nested design of the nanoelectrospray ionization source and the atmospheric pressure chemical ionization ion source to ensure that the analyte entering the ionization zone fully interacts with the nanoESI and APCI primary ion species generated by the composite ion source, and can simultaneously achieve nanoESI and APCI ionization of the sample. This device is combined with a mass spectrometer to achieve simultaneous deep coverage analysis of polar and non-polar metabolites in the sample, with the advantages of high coverage, high sensitivity, and live cell detection. This device also has the advantages of miniaturization, integration, simple structure, easy processing, and convenient operation. The present invention provides a new approach for high-coverage, highly sensitive single-cell metabolomics analysis.

[0072] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization, characterized in that: The invention comprises a drawn glass capillary (1), an insulating medium tube (2), an inner electrode (3), an outer electrode (4), a non-contact electrode (5), a high-voltage AC power supply (7) and a high-voltage pulse power supply (8), wherein the insulating medium tube (2) is coaxially sleeved on the outer side of the drawn glass capillary (1), the front end of the drawn glass capillary (1) is pointed and extends out of the insulating medium tube (2), and the drawn glass capillary (1) is used to hold a sample; the inner electrode (3) and the outer electrode (4) are respectively coated on the drawn glass capillary (1) and the insulating medium tube (2). On the outer wall of the tube (2), a non-contact electrode (5) is placed below the tip of the drawn glass capillary (1); the inner electrode (3) and the outer electrode (4) are connected to a high-voltage AC power supply (7); the non-contact electrode (5) is connected to a high-voltage pulse power supply (8); the high-voltage pulse power supply (8) is turned on to realize a nanoliter electrospray ionization mode; a discharge gas is introduced into the insulating medium tube (2), and the high-voltage pulse power supply (8) and the high-voltage AC power supply (7) are turned on at the same time to realize nanoliter electrospray ionization and atmospheric pressure chemical ionization ionization modes.

2. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 1, characterized in that: The insulating medium tube (2) is a straight hollow tube, and the rear end of the insulating medium tube (2) is connected to the gas storage device via a discharge gas injection tube.

3. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 2, characterized in that: The insulating medium tube (2) is made of glass, quartz or ceramic; the insulating medium tube (2) has a length of 20-100 mm and an inner diameter of 3-6 mm.

4. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 1, characterized in that: The drawn glass capillary (1) is made of glass; the length of the drawn glass capillary (1) is 10-20 mm, and the diameter of the tip is 1-20 μm; the length of the drawn glass capillary (1) extending from the insulating medium tube (2) is 5-20 mm; the tip of the drawn glass capillary (1) is coaxial with the mass spectrometry injection cone (10), and the distance between the tip and the mass spectrometry injection cone (10) is 5-20 mm.

5. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 1, characterized in that: The inner electrode (3) and the outer electrode (4) are both ring-shaped electrodes, and the inner electrode (3) and the outer electrode (4) are both copper foils.

6. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 5, characterized in that: The length of the inner electrode (3) is 5-15 mm; the length of the outer electrode (4) is 10-90 mm.

7. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 1, characterized in that: The non-contact electrode (5) is a sheet electrode, is a copper foil, and is placed 1-10 mm below the tip of the drawn glass capillary (1).

8. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 1, characterized in that: The voltage of the high-voltage AC power supply (7) is 1-10 kV, the frequency is 0.5-50 kHz, and the power is 1-60 W; the voltage of the high-voltage pulse power supply (8) is 1-10 kV, the frequency is 0.1-10 kHz, and the power is 1-60 W.

9. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 1, characterized in that: It also includes a position adjustment device (9) and a connecting assembly (6), wherein the connecting assembly (6) is used to fix the insulating medium tube (2), the position adjustment device (9) is connected to the connecting assembly (6), and the position adjustment device (9) is used to adjust the spatial position of the composite ionization source.

10. The coaxial nano-electrospray atmospheric pressure chemical ionization composite ionization source for ionization according to claim 1, characterized in that: The discharge gas is one of nitrogen, helium, argon, air and carbon dioxide or any mixture thereof; the flow rate of the discharge gas is 0.01-1.0 L / min; The sample is a liquid sample or a cell sample.

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