Dual-sheath liquid micro- and nano-electrospray ion source system and method of use

Abstract

This invention provides a dual-sheath liquid micro / nano-liquid conical electrospray mass spectrometry ion source system and its usage method, relating to the field of mass spectrometry analysis. It includes a dual-sheath liquid tubing module, an integrated micro-flow pump control module, and a high-voltage potential loading module. The dual-sheath liquid tubing module comprises a sample quartz capillary, an inner sheath liquid quartz capillary, and an outer sheath liquid stainless steel tube arranged coaxially, with the outlet ends of these tubing arranged sequentially to form a three-tiered, embedded coaxial outlet with a concave-convex structure. The integrated micro-flow pump control module is connected to the dual-sheath liquid tubing module to deliver the sample liquid, inner sheath liquid, and outer sheath liquid. The output end of the high-voltage potential loading module is connected to the inner sheath liquid quartz capillary. The inner sheath liquid provides the ionization environment, while the outer sheath liquid reduces surface tension, assists in rapid desolvation, and forms a protective barrier. This dual collaboration significantly improves ionization efficiency and spray stability, reduces matrix effect interference, and greatly enhances the efficiency, sensitivity, and applicability of mass spectrometry analysis.

Description

[0001] This application claims priority to Chinese Patent Application No. 202510679623.4, filed with the Chinese Patent Office on May 26, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of mass spectrometry analysis technology, specifically to a dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system and its usage. Background Technology

[0003] Mass spectrometry, as a highly sensitive and selective analytical technique, plays a crucial role in modern analytical chemistry, biochemistry, and environmental science. Electrospray ionization (ESI), in particular, is widely used in various mass spectrometry analyses due to its applicability to liquid samples. Traditional ESI uses a high-voltage electric field to convert liquid into charged droplets, which then evaporate into gaseous ions that enter the mass spectrometer for analysis. However, traditional ESI still has many limitations when dealing with complex samples.

[0004] In the analysis of high-salt matrices and complex biological samples, conventional ESI ion sources are significantly hampered by coexisting substances in the sample, which can significantly reduce the ionization efficiency of target molecules, leading to decreased signal intensity and poor reproducibility. Existing research indicates that the matrix effect is one of the main factors affecting the efficiency of electrospray ionization. Furthermore, conventional ESI has limited adaptability to flow rates, typically performing best in the range of 1 μL / min to 10 μL / min. When the flow rate exceeds or falls below this range, spray stability decreases, resulting in a significant reduction in ionization efficiency.

[0005] Another significant problem is the design of the spray needle. Traditional ESI spray needles are easily contaminated by high-salt matrices or impurities in complex samples during long-term use, leading to signal drift, reduced ionization efficiency, and increased equipment maintenance costs and downtime. This contamination not only affects the reliability of analytical results but also significantly shortens the equipment's lifespan. Traditional ion source designs struggle to avoid matrix effects, especially exhibiting insufficient sensitivity in complex sample analysis. While existing technologies can form a spray using a liquid cone, they also have limitations. For example, Chinese patent CN114109756A discloses a high-conductivity electrolyte aqueous solution electro-jet system and method. This device includes two coaxially arranged capillaries. The inner capillary extends from the outer capillary by a certain length. An inner capillary injection pump delivers an electrolyte aqueous solution to the inner capillary, while an outer capillary injection pump delivers an ionic liquid to the outer capillary. A high potential is applied to the inner and outer capillaries by a high-voltage power supply to directly form a liquid cone spray. While this device can achieve relatively stable liquid cone spraying, the ionic liquid transported in the external capillary only serves as a coating layer to prevent electrolyte evaporation and to form a thin film to stabilize the liquid cone; its contribution to improving mass spectrometry ionization efficiency is not clearly demonstrated. Furthermore, the high potential directly applied to the double-layer capillary can easily lead to uneven electric field distribution. The primary application scenario for this device is in electrospray thruster applications, focusing on addressing the problem of liquid evaporation under vacuum conditions.

[0006] In the field of single-cell analysis, existing technologies also have limitations. For example, Chinese patent CN109950126A discloses a high-throughput single-cell electrospray mass spectrometry device, which includes three layers of coaxially arranged capillary nozzles. The inner capillary delivers cell suspension, the middle capillary delivers sheath extractant, and the outer capillary forms an electrospray. Although this device can achieve cell sorting before entering the mass spectrometer for analysis, it still retains the traditional nozzle structure (10 μm tip diameter), making it prone to contamination and clogging. Furthermore, the high voltage is directly applied to the outer wall of the outermost capillary nozzle, resulting in uneven electric field distribution and potential spray instability. This device primarily focuses on cell sorting and fragmentation rather than optimizing ionization efficiency and spray stability, thus facing significant challenges when processing complex matrix samples.

[0007] Furthermore, existing ion source technologies also have limitations in their ability to support online chemical reactions. Traditional ESI technology is restricted in its application to real-time analysis, making it difficult to support the realization of online chemical reactions, which is increasingly valued in dynamic sample analysis and metabolic research.

[0008] In summary, existing electrospray mass spectrometry ion source technologies still have significant shortcomings in terms of ionization efficiency, spray stability, anti-fouling ability, flow rate adaptability, and online chemical reaction capability. There is an urgent need for a new ion source technology to overcome these limitations and improve the application efficiency and reliability of mass spectrometry analysis in complex samples. Summary of the Invention

[0009] The purpose of this invention is to provide a dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system and its usage method. By combining innovative technologies such as needle-free design, dual-sheath liquid system, optimized electric field loading and integrated micro-flow pump control, it solves the core problems faced by traditional electrospray ion sources in the analysis of high-salt and complex samples, and significantly improves the efficiency, sensitivity, stability and applicability of mass spectrometry analysis.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system, comprising: The dual-sheath fluid tubing module includes a sample quartz capillary, an inner sheath fluid quartz capillary, and an outer sheath fluid stainless steel tube arranged coaxially. The sample quartz capillary is located at the center, the inner sheath fluid quartz capillary wraps around the sample quartz capillary, and the outer sheath fluid stainless steel tube wraps around the inner sheath fluid quartz capillary. The outlet ends of the sample quartz capillary, the inner sheath fluid quartz capillary, and the outer sheath fluid stainless steel tube are arranged sequentially to form a three-level layered embedded coaxial outlet with a concave-convex structure. An integrated micro-flow pump control module is connected to the dual-sheath liquid pipeline module and is used to deliver sample liquid to the sample quartz capillary, inner sheath liquid to the inner sheath liquid quartz capillary, and outer sheath liquid to the outer sheath liquid stainless steel tube, respectively; the flow rate of the sample liquid, inner sheath liquid, or outer sheath liquid delivered by the integrated micro-flow pump control module is less than or equal to 20 μL / min; A high-voltage potential loading module is provided, the output of which is connected to the inner sheath liquid quartz capillary. This module transmits the high-voltage electric field to the three-level layered embedded coaxial outlet through the inner sheath liquid, ensuring that the high-voltage electric field is evenly distributed at the three-level layered embedded coaxial outlet. This avoids interference with sample analysis caused by localized heating of the wires that directly apply the electric field at the three-level layered embedded coaxial outlet.

[0011] Among them, the three-level layered embedded coaxial outlet forms a liquid cone under the action of a high-voltage electric field, generating charged ions.

[0012] Furthermore: the inner diameter of the sample quartz capillary is 30μm-70μm, and the outer diameter is 100μm-200μm; the inner diameter of the inner sheath fluid quartz capillary is 200μm-250μm, and the outer diameter is 300μm-400μm; the inner diameter of the outer sheath fluid stainless steel tube is 500μm-600μm, and the outer diameter is 1000μm-1500μm. The sample quartz capillary at the three-level layered embedded coaxial outlet has its opening recessed by 2mm-5mm compared to the opening of the inner sheath liquid quartz capillary. The opening of the inner sheath liquid quartz capillary protrudes 0.5mm-2mm beyond the opening of the outer sheath liquid stainless steel tube, thus forming functional gradient field partitions for the sample premixing zone, charge predisposition zone, surface tension attenuation zone, and rapid desolvation zone.

[0013] Furthermore, the dual-sheath fluid pipeline module also includes a PEEK tee and connector for connecting and fixing the sample quartz capillary, the inner sheath fluid quartz capillary, and the outer sheath fluid stainless steel tube; wherein, the PEEK tee includes two T-shaped PEEK tees, which are used to realize independent unidirectional delivery of the inner sheath fluid and the outer sheath fluid respectively. The T-type PEEK tee is divided into a first T-type tee and a second T-type tee. The sample quartz capillary is inserted from the main inlet of the first T-type tee and passes through the main outlet of the first T-type tee, the main inlet of the second T-type tee, and the main outlet of the second T-type tee in sequence. One end of the inner sheath liquid quartz capillary wraps around the sample quartz capillary and is connected to the main pipeline output port of the first T-shaped tee, while the other end passes through the main pipeline input port and the main pipeline output port of the second T-shaped tee in sequence. One end of the outer sheath fluid stainless steel tube wraps around the inner sheath fluid quartz capillary tube that extends out of the main pipeline outlet of the second T-type tee and is connected to the main pipeline outlet of the second T-type tee. The sample quartz capillary, inner sheath fluid quartz capillary, and outer sheath fluid stainless steel tube are all connected to a T-type PEEK tee via a connector.

[0014] Furthermore: the integrated micro-flow pump control module includes three integrated micro-flow pump control modules with identical structures: Integrated Micro-flow Pump Control Module 1, Integrated Micro-flow Pump Control Module 2, and Integrated Micro-flow Pump Control Module 3; Integrated Micro-flow Pump Control Module 1 delivers outer sheath liquid to the outer sheath liquid stainless steel tube, Integrated Micro-flow Pump Control Module 2 delivers inner sheath liquid to the inner sheath liquid quartz capillary tube, and Integrated Micro-flow Pump Control Module 3 delivers sample liquid to the sample quartz capillary tube; The integrated micro-flow pump control module 1, integrated micro-flow pump control module 2, and integrated micro-flow pump control module 3 all include: a stepper motor, used to independently control the flow rate of sample liquid, inner sheath liquid, or outer sheath liquid; A lead screw and a lead screw nut are provided. The lead screw is connected to the stepper motor, and the lead screw nut is provided on the lead screw to convert the rotational motion of the stepper motor into linear motion. Luer connector glass syringe, used for storing sample solution, inner sheath solution or outer sheath solution; A miniature linear slide rail and a slider are used to ensure the stable advancement of the push rod of the Luer connector glass syringe; one end of the slider clamps the outer shell of the Luer connector glass syringe and is set on the miniature linear slide rail, and the other end of the slider is connected to the lead screw nut; The miniature linear slide rail is also equipped with a fixing block, and the push rod of the Luer connector glass syringe abuts against the fixing block.

[0015] After the output end of the Luer connector glass syringe of the integrated micro-flow pump control module is connected to the branch input port of the second T-type three-way connector through the connector, it is connected to the stainless steel tube of the outer sheath fluid. After the output end of the Luer connector glass syringe of the integrated micro-flow pump control module 2 is connected to the branch input port of the first T-type three-way connector through the connector, it is connected to the inner sheath liquid quartz capillary. The output end of the Luer connector glass syringe of the integrated micro-flow pump control module three is connected to the sample quartz capillary via a connector.

[0016] Furthermore, it also includes: A multi-axis linkage microscopic positioning module includes a spatial position fine-tuning component and a digital microscope component. The spatial position fine-tuning component is used to fine-tune the spatial position of the liquid cone and the mass spectrometer inlet, and the digital microscope component is used to display the position of the liquid cone and the mass spectrometer inlet and the liquid cone spray state in real time. The mass spectrometry interface connection module is used to fix the dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system onto the mass spectrometer.

[0017] Furthermore: the inner sheath fluid is an aqueous solution containing volatile organic acids / bases, used to provide an ionization environment for sample molecules and to apply a high voltage potential over a long distance; the outer sheath fluid is an organic solvent, used to reduce the surface tension of the liquid and accelerate the evaporation of the droplets.

[0018] The present invention also provides a method for using the above-described dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system, comprising the following steps: S1: The integrated micro-flow pump control module delivers sample liquid to the sample quartz capillary, inner sheath liquid to the inner sheath liquid quartz capillary, and outer sheath liquid to the outer sheath liquid stainless steel tube based on a preset flow rate ratio. S2: Apply a high-voltage electric field to the inner sheath fluid through the high-voltage potential loading module, so that the high-voltage electric field is conducted to the three-level layered embedded coaxial outlet through the inner sheath fluid; S3: Under the action of a high voltage electric field, a liquid cone spray is formed at the three-level layered embedded coaxial outlet. The sample molecules are ionized through droplet pyrolysis and rapid solvent evaporation. S4: Adjust the liquid cone spray through the multi-axis linkage micro-positioning module to guide ions into the mass spectrometer for analysis, so as to achieve the best mass spectrometry signal response.

[0019] Further: In step S1, the flow rate ratio of the sample liquid, inner sheath liquid and outer sheath liquid is 0.5-1:0.5-2:1-10; preferably 0.5:1:2.

[0020] The present invention also provides the dual-sheath liquid micro / nano liquid conical electrospray mass spectrometry ion source system described above, or the application of the method using the dual-sheath liquid micro / nano liquid conical electrospray mass spectrometry ion source system in the mass spectrometry analysis of high-salt matrix samples, biological samples or single cells.

[0021] High-salt matrix samples refer to samples using 10mM PBS (phosphate buffered saline) or physiological saline as the matrix.

[0022] In summary, this invention features a three-tiered embedded coaxial outlet, multifunctional gradient sheath fluid synergy, and a modular compact design. Through staged sheath fluid encapsulation, a delayed sheath fluid loading mechanism, and optimized electric field zoning, it forms a functional gradient field encompassing sample premixing, charge predisposition, surface tension attenuation, and rapid desolvation. The inner sheath fluid provides the ionization environment, while the outer sheath fluid reduces surface tension, assists in rapid desolvation, and forms a protective barrier. This dual synergy of the functionalized inner and outer sheath fluids significantly improves ionization efficiency and spray stability, while reducing matrix effect interference. This invention effectively solves the problems of contamination and clogging, poor salt tolerance, and low ionization efficiency faced by traditional electrospray ionization sources in the analysis of high-salt and complex biological samples. It significantly improves the efficiency, sensitivity, and applicability of mass spectrometry analysis, making it particularly suitable for the analysis of complex high-salt biological samples and single-cell research.

[0023] Compared with the prior art, the present invention has the following advantages: I. This invention employs a spray-free needle design, eliminating the easily contaminated metal nozzles or capillary needle structures created by laser ablation in traditional electrospray systems. Instead, it utilizes a three-stage, layered, embedded coaxial outlet to directly form a liquid cone, fundamentally solving the problems of signal drift and reduced ionization efficiency caused by nozzle contamination or clogging. This design significantly improves the device's resistance to contamination in high-salt matrices and complex biological sample analysis, extends equipment lifespan, and reduces maintenance frequency and downtime.

[0024] II. The innovative dual-sheath fluid system in this invention significantly improves ionization efficiency and stability through the synergistic effect of the inner and outer sheath fluids. The inner sheath fluid (e.g., 1% formic acid solution) provides a stable protonation environment for the sample, while the outer sheath fluid (e.g., acetonitrile) greatly enhances spray stability by reducing surface tension and forming a stable Taylor cone. This dual-sheath fluid design significantly reduces the inhibitory effect of matrix effects on ionization efficiency, offering significant advantages, particularly for the analysis of high-salt samples. This results in a significant improvement in the sensitivity and accuracy of complex sample analysis, enabling single-cell analysis.

[0025] Third, this invention optimizes the electric field distribution by applying high pressure over a long distance to the inner sheath liquid, avoiding problems such as unstable flow rate, heat release from the wires, and uneven electric field distribution caused by the traditional internal wires at the liquid outlet. The uniformly distributed electric field makes the liquid cone formation more stable, and the stretching, evaporation, and pyrolysis processes of the droplets in the electric field are more efficient, thereby further improving ionization efficiency and signal stability.

[0026] Fourth, the three-layer coaxial liquid flow design of this invention, combined with a precisely controlled flow rate ratio (e.g., 1:2:4), achieves hydrodynamic balance of the sample liquid, inner sheath liquid, and outer sheath liquid at the outlet, ensuring the stability of the spray cone shape and spray efficiency. This design significantly expands the device's adaptability to flow rates, enabling it to meet various flow rate requirements from nanoliters to microliters.

[0027] Fifth, this invention can be applied to mass spectrometry analysis. By designing a reasonable spatial layout for each module, the modular and compact configuration reduces the size of the core components of the system to 300mm×150mm×200mm, thus meeting the requirements for small and portable use. Attached Figure Description

[0028] Figure 1 A schematic diagram of the structure of a dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system; Figure 2 This is a schematic diagram of a half-section of the dual-sheath fluid piping module; Figure 3 for Figure 2 Simplified diagram after scaling; Figure 4 This is a structural schematic diagram of the integrated micro-flow pump control module. Figure 5 This is a structural schematic diagram of the spatial positioning fine-tuning component; Figure 6 This is a schematic diagram illustrating the relationship between voltage and spray stability. Figure 7 This is a schematic diagram illustrating the relationship between spray stability and signal intensity for different sheath fluids; Figure 8 A flow rate ratio optimization diagram; Figure 9 A comparison chart showing the presence and absence of external sheath fluid; Figure 10 Linearity detection curve for standard substances; Figure 11 For the detection limit test chart; Figure 12 This is a chart showing the precision test results within the day. Figure 13 This is a chart showing the precision test results during the day. Figure 14 This is a diagram showing the salt tolerance test results. Figure 15 Image of peripheral blood B lymphocytes (8226) metabolites in a patient with multiple myeloma; Figure 16 Image of metabolite detection in human acute myeloid leukemia cells (cell-3). Figure 17 Image showing the detection of metabolites in human myeloma cell-H929 cells; Figure 18 Image showing the detection of metabolites in human monocytic leukemia cell-1 cells; Figure 19 Distribution of metabolites in peripheral blood B lymphocytes (8226) from individuals with multiple myeloma; Figure 20 Distribution map of metabolites in human acute myeloid leukemia cells (C-3 cells); Figure 21 Distribution map of metabolites in human myeloma cells-H929; Figure 22 Distribution map of metabolites in human monocytic leukemia cell-1 cells; Figure 23 This is a PCA analysis diagram of four types of cellular metabolomics.

[0029] In the picture: 1. Dual-sheath fluid piping module; 11. Outer sheath fluid stainless steel tube; 12. Inner sheath fluid quartz capillary tube; 13. Sample quartz capillary tube; 14. Tee; 141. First T-type tee; 142. Second T-type tee; 15. Outer sheath fluid; 16. Inner sheath fluid; 17. Sample fluid; 18. Liquid cone spray; 2. Integrated micro-flow pump control module; 21. Integrated micro-flow pump control module one; 211. Stepper motor; 212. Lead screw; 213. Coupling; 214. Luer connector 215. Glass syringe; 216. Round connector; 217. Lead screw nut; 218. Slider; 219. Miniature linear slide rail; 220. Fixing block; 221. Push rod; 23. Integrated micro-flow pump control module II; 24. Integrated micro-flow pump control module III; 3. High voltage potential loading module; 35. High voltage output wire; 4. Mass spectrometer interface connection module; 5. Digital microscope assembly; 6. Spatial position fine adjustment assembly; 66. Triaxial stage; 67. M3 screw; 68. T-nut. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] Example 1 like Figure 1 As shown, the present invention provides a dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system, which mainly includes five parts: a dual-sheath liquid pipeline module 1, an integrated micro-flow pump control module 2, a multi-axis linkage micro-positioning module, a high-voltage potential loading module 3, and a mass spectrometry interface connection module 4.

[0033] like Figures 2-3 As shown, where Figure 2 This is a partial cross-sectional view of the actual structure of the dual-sheath fluid piping module 1, but the structure involved is too small, so it is not shown here. Figure 2 Add on the basis Figure 3 , Figure 3 To enlarge Figure 2 A simplified structural diagram of the sample quartz capillary 13, inner sheath fluid quartz capillary 12, and outer sheath fluid stainless steel tube 11, after proportional adjustments, clearly illustrates the installation and fit relationships between the components of the dual sheath fluid pipeline module 1. The dual sheath fluid pipeline module 1 includes a sample quartz capillary 13, an inner sheath fluid quartz capillary 12, and an outer sheath fluid stainless steel tube 11 arranged coaxially. In some embodiments, the sample quartz capillary 13 is used for precise delivery of the sample solution; the sample quartz capillary 13 has an outer diameter of 200 μm and an inner diameter of 50 μm. The inner sheath fluid quartz capillary 12 has an outer diameter of 365 μm and an inner diameter of 250 μm. The outer sheath fluid stainless steel tube 11 has an outer diameter of 1000 μm and an inner diameter of 500 μm. These three capillaries are connected and fixed via two T-shaped PEEK tees 14 and a connector, enabling independent, unidirectional delivery of the inner sheath fluid 16 and the outer sheath fluid 15.

[0034] The T-type PEEK tee is divided into a first T-type tee 141 and a second T-type tee 142. The sample quartz capillary 13 is inserted from the main pipeline inlet of the first T-type tee 141 and passes through the main pipeline outlet of the first T-type tee 141, the main pipeline inlet of the second T-type tee 142, and the main pipeline outlet of the second T-type tee 142 in sequence. One end of the inner sheath fluid quartz capillary 12 wraps around the sample quartz capillary 13 and is connected to the main pipeline output port of the first T-shaped tee 141, while the other end passes through the main pipeline input port and the main pipeline output port of the second T-shaped tee 142 in sequence. One end of the outer sheath fluid stainless steel tube 11 wraps around the inner sheath fluid quartz capillary tube 12 that extends out of the main pipeline outlet of the second T-shaped tee 142, and is connected to the main pipeline outlet of the second T-shaped tee 142. The sample quartz capillary 13, the inner sheath fluid quartz capillary 12, and the outer sheath fluid stainless steel tube 11 are all connected to the T-type PEEK tee 14 via connectors.

[0035] The sample quartz capillary 13 at the three-level layered embedded coaxial outlet has its opening recessed by 2mm-5mm compared to the opening of the inner sheath liquid quartz capillary 12. The openings of the inner sheath liquid quartz capillary 12 protrude 0.5mm-2mm from the opening of the outer sheath liquid stainless steel tube 11, thus forming functional gradient field zones for sample premixing, charge predisposition, surface tension attenuation, and rapid desolvation. In this embodiment, a European standard 120mm×20mm×200mm aluminum profile, M3 screws 62, and T-nuts 63 are used to fix two T-shaped tees 14 to the grooves of the aluminum profile, and the ports of the outer sheath liquid tees 14 are adjusted to be flush with the ports of the aluminum profile.

[0036] like Figure 1As shown, the integrated micro-flow pump control module 2 includes three integrated micro-flow pump control modules with the same structure: integrated micro-flow pump control module 1 21, integrated micro-flow pump control module 22, and integrated micro-flow pump control module 3 23. These modules are used to deliver outer sheath liquid 15 to the outer sheath liquid stainless steel tube 11, deliver inner sheath liquid 16 to the inner sheath liquid quartz capillary tube 12, and deliver sample liquid 17 to the sample quartz capillary tube 13, respectively.

[0037] Combination Figure 4 As shown, taking the integrated micro-flow pump control module 21 as an example, the integrated micro-flow pump control module 21 includes: Stepper motor 211 is used to independently control the flow rate of sample liquid 17, inner sheath liquid 16 or outer sheath liquid 15; The lead screw 212 and lead screw nut 216 are provided. The lead screw 212 is connected to the stepper motor 211 through a coupling 213. The lead screw nut 216 is provided on the lead screw 212 and is used to convert the rotational motion of the stepper motor 211 into linear motion. Luer connector glass syringe 214, used to store sample solution 17, inner sheath solution 16 or outer sheath solution 15; The miniature linear slide rail 218 and the slider 217 are used to ensure the stable advancement of the push rod 220 of the Luer connector glass syringe 214; one end of the slider 217 clamps the outer shell of the Luer connector glass syringe 214 and is set on the miniature linear slide rail 218, and the other end of the slider 217 is connected to the lead screw nut 216. The miniature linear slide rail 218 is also provided with a fixing block 219, and the push rod 220 of the Luer connector glass syringe 214 abuts against the fixing block 219.

[0038] The output end of the Luer connector glass syringe of the integrated micro-flow pump control module 21 is connected to one end of the input pipeline through the round connector 215. The other end of the input pipeline is connected to the branch input port of the second T-type tee and then connected to the outer sheath fluid stainless steel tube 11. The output end of the Luer connector glass syringe of the integrated micro-flow pump control module 22 is connected to one end of the input pipeline through the round connector 215. The other end of the input pipeline is connected to the branch input port of the first T-type tee and then connected to the inner sheath liquid quartz capillary 12. The output end of the Luer connector glass syringe of the integrated micro-flow pump control module 323 is connected to one end of the input pipeline through the round connector 215, and the other end of the input pipeline is connected to the sample quartz capillary 13.

[0039] The integrated micro-flow pump control module connects each liquid path (sample liquid 17, inner sheath liquid 16, and outer sheath liquid 15) to an independent syringe and stepper motor 211. Miniature linear guides and sliders ensure stable syringe plunger movement, preventing flow rate fluctuations. Stepper motor 211 drives the syringe to push liquid into the sample quartz capillary 13, the inner sheath liquid quartz capillary 12, and the outer sheath liquid stainless steel tube 11, controlling the flow rate with microliter precision. The stepper motor 211 is driven by an ESP32 chip controlled by an A4988, precisely controlling the liquid flow rate and supporting independent adjustment of multiple flow paths.

[0040] To achieve fine-tuning of the spatial position of the liquid cone spray 18 and the mass spectrometer inlet, this invention also includes a multi-axis linkage microscopic positioning module to obtain optimal mass spectrometry signal response. The multi-axis linkage microscopic positioning module includes a spatial position fine-tuning component 6 and a digital microscope component 5, such as... Figure 1 and Figure 5 As shown, this invention assembles the aluminum profile groove in the pre-assembled dual-sheath liquid pipeline with a LD60-CM-2 (XYZ axis three-dimensional) manually adjustable three-axis stage 61 using M3 screws 62 and T-nuts 63, thereby adjusting the three-dimensional spatial position of the liquid cone spray 18 and the mass spectrometer inlet. The aluminum profile side groove is also assembled with a commercially available digital electron microscope using M3 screws 62 and T-nuts 63, enabling real-time display and recording of the liquid cone spray 18's position relative to the mass spectrometer inlet and the liquid cone spray's position.

[0041] The high-voltage potential loading module 3 uses an external high-voltage power supply to provide a 3kV~6kV high-voltage electric field. This electric field acts directly on the liquid interface of the three-stage layered embedded coaxial outlet through the inner sheath liquid 16. The high-voltage potential loading module 3 connects to the inner sheath liquid 16 flow path via a T-type PEEK tee connector 14 through the high-voltage output wire 31, loading the output high voltage into the inner sheath liquid 16. This allows the high-voltage electric field to be applied remotely to the outlet end through the inner sheath liquid 16, resulting in a more uniform and stable electric field distribution at the three-stage layered embedded coaxial outlet. The high-voltage grounding wire shares a common ground with the mass spectrometer. The high-voltage electric field causes the liquid cone spray 18 to spray towards the mass spectrometer inlet, generating charged ions. This design avoids problems such as unstable flow rate, wire heat release, and uneven electric field distribution caused by built-in wires at the outlet. Furthermore, the use of highly insulated T-type PEEK connectors and PEEK fittings for a fully enclosed connection with the inner sheath liquid PEEK tube ensures the safety of the mass spectrometer and operators.

[0042] The device of this invention is a lightweight and compact ion source. It can be fixed with M5 screws through four channels in a 120mm×80mm×200mm aluminum profile. It is compatible with ion source connection modules of ThermoFisher Q-Exactive mass spectrometers, including but not limited to those of ThermoFisher Q-Exactive mass spectrometers. The three-level layered embedded multifunctional dual-sheath electrohydraulic spray mass spectrometry ion source system can be directly fixed on the mass spectrometer through the mass spectrometry interface connection module 4.

[0043] Example 2 In this embodiment, the length relationship of the inlet of the sample quartz capillary 13, the inlet of the inner sheath fluid quartz capillary 12, and the inlet of the outer sheath fluid stainless steel tube 11 at the three-stage layered embedded coaxial outlet is any one of the following: all three are flush; any two are flush and protrude from the other; any one protrudes and the other two are flush; or the three are staggered in sequence. In one embodiment, the staggered arrangement of the three can be as follows: the inlet of the sample quartz capillary 13 protrudes from the inlet of the inner sheath fluid quartz capillary 12, and the inlet of the inner sheath fluid quartz capillary 12 protrudes from the inlet of the outer sheath fluid stainless steel tube 11.

[0044] In the embodiments of this application, by controlling the different liquid flow rates and / or flow rates in the three tubes, the fluids in the tubes can gradually interact before ionization, forming laminar flow and a stable liquid cone.

[0045] In one embodiment, the outlet end of the sample quartz capillary 13 protrudes further than the outlet end of the inner sheath fluid quartz capillary 12, for example, by 2 mm–5 mm. The outlet end of the inner sheath fluid quartz capillary 12 protrudes further than the outlet end of the outer sheath fluid stainless steel tube 11, for example, by 0.5 mm–2 mm. This creates a hierarchical coaxial geometry, allowing the fluids to interact gradually before ionization, rather than instantaneously contacting each other on a single outlet plane, thus facilitating laminar flow and the formation of a stable liquid cone.

[0046] The remaining structure of the dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system in this embodiment is the same as that in Embodiment 1 above, and will not be described again here.

[0047] Example 3 This invention also provides a method for using a dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system, comprising the following steps: S1: The integrated micro-flow pump control module 2 delivers sample liquid 17 to the sample quartz capillary 13, inner sheath liquid 16 to the inner sheath liquid quartz capillary 12, and outer sheath liquid 15 to the outer sheath liquid stainless steel tube 11 based on the preset flow rate ratio. In a preferred embodiment, the flow rate ratio of sample liquid 17, inner sheath liquid 16, and outer sheath liquid 15 is 1:2:4.

[0048] S2: Apply a high-voltage electric field to the inner sheath fluid 16 through the high-voltage electric potential loading module 3, so that the high-voltage electric field is conducted to the three-level layered embedded coaxial outlet through the inner sheath fluid 16; S3: Under the action of a high voltage electric field, a liquid cone spray 18 is formed at the three-level layered embedded coaxial outlet. The ionization of sample molecules is achieved through droplet pyrolysis and solvent evaporation. S4: Adjust the liquid cone spray through the multi-axis linkage micro-positioning module to guide ions into the mass spectrometer for analysis, so as to achieve the best mass spectrometry signal response.

[0049] The working principle of this invention is mainly reflected in the following aspects: The first step is the formation of the spray (the Taylor cone). This invention eliminates the need for traditional metal spray needles or capillary needles drawn by laser ablation, avoiding clogging problems caused by salt deposition or impurities. The high voltage output is directly applied to the inner sheath fluid 16, allowing the high-voltage electric field to be applied over a long distance through the inner sheath fluid 16 to directly form the liquid cone spray 18 at the outlet. This invention, through the tip spray formed by the liquid cone itself, further increases the usable voltage and effectively avoids nozzle clogging problems caused by needle tip discharge and ablation due to excessively high voltage.

[0050] Secondly, there is droplet fragmentation and solvent evaporation. Under the influence of the electric field, the sprayed droplets become charged and rapidly decrease in volume. As the droplet solvent evaporates, the surface charge density of the droplets continuously increases, eventually exceeding the limit of the droplet surface tension (the so-called Rayleigh limit), causing the droplets to break up into smaller charged droplets (a phenomenon known as a "Coulomb explosion"). The high pressure ensures that this series of processes continues, causing the liquid to split into tiny charged droplets. In this invention, the outer sheath fluid uses organic reagents, which not only reduce the surface tension of the droplets but also accelerate the evaporation of the droplet solvent, further improving the ionization efficiency.

[0051] Thirdly, there is molecular ionization. Under the influence of a high-voltage electric field, the droplet gradually evaporates until only the molecules originally dissolved in the solution remain. The complete evaporation of the solvent keeps the molecules in the solution charged, generating charged gaseous ions (such as [M+H], [MH], etc.). The high-voltage electric field ensures sufficient ionization efficiency, thereby converting the sample molecules into charged ions that can be detected by a mass spectrometer.

[0052] Finally, it accelerates the migration of charged ions towards the mass spectrometer. The high-voltage electric field can also provide an electric force, accelerating the migration of charged gaseous ions from the spray region towards the vacuum system inlet of the mass spectrometer. This is crucial for improving the sensitivity and detection efficiency of the mass spectrometer.

[0053] The inner sheath fluid is an aqueous solution containing volatile organic acids or organic bases, used to provide an ionizing environment for sample molecules and to apply high-voltage potentials over long distances. The outer sheath fluid is an organic solvent, used to reduce the surface tension of the liquid and accelerate droplet evaporation.

[0054] In one embodiment, the aqueous solution of the organic acid may be a 0.5%-1% aqueous solution of formic acid. The aqueous solution of the organic base may be a 0.5%-1% aqueous solution of ammonia.

[0055] The stability of the dual-sheath fluid system is one of the core advantages of this invention. It relies on the synergistic effect of the inner and outer sheath fluids, as well as the precise coordination of fluid dynamics optimization and structural design. The inner sheath fluid is typically an acidified aqueous solution (e.g., 0.1% formic acid), which provides a stable ionization environment for sample molecules by increasing protonation capability. This environment not only improves ionization efficiency but also provides a fundamental fluid dynamic equilibrium for the sample during liquid cone formation. By encapsulating the sample fluid, the inner sheath fluid forms a uniform flow at the three-tiered, embedded coaxial outlet, effectively mitigating the potential instability caused by sample fluid flow rate fluctuations on the spray cone. The outer sheath fluid serves multiple functions: First, the outer sheath fluid uses a low surface tension solvent (such as acetonitrile), which reduces the influence of liquid surface tension at the three-tiered embedded coaxial outlet, making it easier for the liquid cone to form a stable spray cone (Taylor cone) under the influence of an electric field. Second, the outer sheath fluid, with its high flow rate, encapsulates the inner sheath fluid and sample liquid, diluting high-salt or other complex matrix components in the sample and reducing the adverse effects of matrix effects on liquid spray. In addition, the high-speed flow of the outer sheath fluid forms a protective barrier between the three-tiered embedded coaxial outlet and the outside air, reducing the impact of external disturbances such as ambient airflow and temperature fluctuations on spray stability.

[0056] Another advantage of this invention lies in its optimized hydrodynamics. The stability of a dual-sheath fluid system is closely related to the flow rate ratio. In this invention, the flow rate ratio of the sample fluid, inner sheath fluid, and outer sheath fluid is experimentally optimized (e.g., 1:2:4) to achieve a good hydrodynamic equilibrium. The inner sheath fluid has a slightly higher flow rate than the sample fluid, ensuring that the inner sheath fluid encapsulates the sample fluid and provides a uniform flow path. The outer sheath fluid has a significantly higher flow rate than both the inner sheath fluid and the sample fluid; its shear force effectively stabilizes the shape of the liquid cone and further dilutes the interference of the high-salt matrix sample on the spray cone.

[0057] The method of using the dual-sheath liquid micro / nano liquid conical electrospray mass spectrometry ion source system of this embodiment can be applied to the dual-sheath liquid micro / nano liquid conical electrospray mass spectrometry ion source system of Embodiment 1 or Embodiment 2 above.

[0058] Example 4 The present invention also provides the dual-sheath liquid micro / nano liquid conical electrospray mass spectrometry ion source system described above, or the application of the method using the dual-sheath liquid micro / nano liquid conical electrospray mass spectrometry ion source system in the mass spectrometry analysis of high-salt matrix samples, biological samples or single cells.

[0059] The invention will be further illustrated below with specific application examples.

[0060] Application Case 1 Method for establishing a dual-sheath liquid conical electrospray ionization source system: To verify the performance advantages and optimization methods of the dual-sheath liquid conical electrospray ionization source of the present invention in trace sample detection, the experimental scheme selected glutamine, phenylalanine and Thermo mass spectrometry correction solution (containing caffeine and MRFA) as standard substances, and carried out concentration gradient linear detection and ionization condition optimization experiments in sequence.

[0061] First, prepare the experimental samples and standard solutions. The target substances include glutamine, phenylalanine, caffeine in the Thermo Fisher Scientific mass spectrometry correction solution, and MRFA (tetrapeptide: Met-Arg-Phe-Ala). Accurately weigh the target compounds and prepare a 10 mM standard solution using 50% acetonitrile / water (v / v) as the solvent, adding 0.1% formic acid to improve ionization efficiency. Use a serial dilution method to successively dilute the stock solution to 10 aM, 100 aM, 10 fM, 100 fM, and 10 pM standard working solutions.

[0062] The experiment employed the dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system proposed in this invention, combined with a ThermoFisher mass spectrometer (such as Q-Exactive) for signal detection. The mass spectrometry mode was positive ion mode (ESI+), with a scan range of m / z = 100–1500, a resolution of 70,000, and an S-lens of 40.

[0063] The flow rate of the sample solution is in the range of 0.1 μL / min to 2 μL / min; the flow rate of the inner sheath fluid is in the range of 0.1 μL / min to 5 μL / min; and the flow rate of the outer sheath fluid is in the range of 0.1 μL / min to 10 μL / min.

[0064] Key parameter optimization designs included voltage optimization, outer sheath fluid type, flow rate ratio, and comparisons with and without outer sheath fluid. For voltage optimization, spray voltage ranges of 3.5 kV, 4.0 kV, 5.0 kV, 5.5 kV, and 6.0 kV were set, and their effects on the liquid cone shape and mass spectrometry signal intensity were tested. Regarding the outer sheath fluid type, with sample fluid, inner sheath fluid, and outer sheath fluid flow rates of 0.5 μL / min, 1 μL / min, and 2 μL / min, respectively, acetonitrile, water, and isopropanol were tested as outer sheath fluids to analyze the differences in spray stability and ionization efficiency among different solvents. Regarding flow rate ratios, the inner sheath fluid was prepared using a 0.1% formic acid aqueous solution, delivered at flow rates of 0.5 μL / min, 1.0 μL / min, and 2.0 μL / min; the outer sheath fluid was delivered at flow rates of 1.0 μL / min, 2.0 μL / min, 5.0 μL / min, and 10.0 μL / min, respectively, and acetonitrile was tested accordingly; the sample solution was delivered directly at flow rates of 0.5 μL / min and 1 μL / min, respectively, as the target working solution. For comparisons with and without outer sheath fluid, the stability of the spray and the mass spectrometry response were tested under conditions with and without outer sheath fluid (acetonitrile).

[0065] Under optimized conditions (spray voltage 5.5 kV), with acetonitrile as the outer sheath fluid and a flow rate ratio of 0.5:1:2 μL / min (sample solution: inner sheath fluid: outer sheath fluid), gradient detection of glutamine, phenylalanine, caffeine, and MRFA was performed. The concentration range was 10 aM to 10 pM. The mass spectrometric signal intensity of each target analyte was measured, and concentration-signal linearity curves were plotted.

[0066] For intraday precision experiments, six independent injection measurements were performed on the same day using a 10 fM working solution as the test sample. The working solution was re-injected before each measurement to ensure reproducibility of the spray pattern upon device startup. The mass spectrometric signal intensities of glutamine, phenylalanine, caffeine, and MRFA were recorded, and the relative standard deviation (RSD) was calculated to assess intraday precision. For interday precision experiments, three independent injection measurements were performed daily over three consecutive days using the 10 fM working solution as the test sample. The spray parameters were reconfigured and the working solution was re-injected before each day's measurement. The mass spectrometric signal intensities (peak areas) of glutamine, phenylalanine, caffeine, and MRFA were recorded, and the relative standard deviation (RSD) was calculated to assess interday precision.

[0067] Experimental results show that the liquid cone exhibits the best stability, the highest signal response strength, and the lowest signal noise at 5.0 kV. Figure 6 As shown, below 5kV and above 5.5kV, the excessively strong electric field causes liquid cone fluctuations and signal instability. In the outer sheath liquid type experiment, acetonitrile and isopropanol performed better during spraying due to their high volatility and low surface tension. In contrast, ... Figure 7As shown, acetonitrile exhibits greater stability and higher signal intensity when used as the outer sheath fluid compared to isopropanol. In the flow rate mixing experiment, as... Figure 8 As shown, when the flow rate ratio is (0.5:1:2 μL / min), the synergistic effect of the inner and outer sheath fluids is optimal, the liquid cone is stable, and the mass spectrometry response is the best. Figure 9 As shown, in the comparison experiment with and without external sheath fluid, the liquid cone shape was difficult to maintain and the signal was unstable during spraying when there was no external sheath fluid; when the external sheath fluid (acetonitrile) was present, the spray stability and signal intensity were significantly improved.

[0068] In linear detection experiments, such as Figures 10-11 As shown, gradient concentration detection (10 / 50 / 100 / 150 / 200 fM) and detection line analysis in the low concentration range (1 aM~200 fM) were performed for glutamine, phenylalanine, caffeine, and MRFA under optimized conditions. The results showed that the R² of each linear equation was greater than 0.98, exhibiting good linearity and low detection limits over a wide range of low concentrations. Figures 12-13 As shown, in the repeatability experiment, the RSD of each target substance was less than 15% in both intra-day and inter-day precision tests, indicating that the device has good repeatability and stability when conducting experiments at different times. Figure 14 As shown, in the salt tolerance experiment, 1 μg / mL bovine serum albumin (BSA) standard solutions were prepared using phosphate buffered saline (PBS) of different concentrations. The solutions were then detected using the dual-sheath liquid ion source, nanospray ion source, and conventional electrospray ion source of this invention, respectively. The relative abundance of BSA signals was obtained. The results showed that the dual-sheath liquid ion source of this invention is superior to the nanospray ion source and significantly superior to the conventional electrospray ion source, indicating that the dual-sheath liquid ion source of this invention has better salt tolerance and significant advantages in the detection and analysis of high-salt biological samples.

[0069] Application Case 2 Single-cell metabolomics analysis: Another important application of this invention is single-cell metabolomics research. By selecting four myeloma-related cell types, such as human multiple myeloma peripheral blood B lymphocytes (8226) (RPMI-8226), human acute myeloid leukemia cells-3 (OCI-Aml-3), human myeloma cells-H929 (NCI-H929), and human monocytic leukemia cells-1 (THP1), the device of this invention enables highly sensitive detection of small molecule metabolites in single cells, thereby revealing the metabolic characteristics and heterogeneity of different cell types.

[0070] Sample preparation began first. Four cell lines—RPMI-8226, OCI-Aml-3, NCI-H929, and THP1—were cultured in RPMI-1640 medium containing 10% fetal bovine serum and 1% penicillin-streptomycin at 37°C and 5% CO2. After replacing the medium with sterile PBS, the cell suspension was centrifuged (500g, 5min), the supernatant was discarded, and the cells were washed three times with PBS buffer to remove residual culture medium components. Cells were observed under an inverted microscope. A sample tube (50μm inner diameter, 250μm outer diameter quartz capillary) connected to a sample pump module was used to precisely aspirate individual target cells into the tube for analysis. Additionally, approximately 5 × 10⁴ cells were centrifuged, PBS removed, and pre-cooled methanol solution was added to rapidly quench metabolic activity and extract small molecule metabolites. The extract was centrifuged (14000g, 4°C, 10min), and the supernatant was collected for subsequent mass spectrometry analysis.

[0071] For mass spectrometry detection, the dual-sheath fluid micro / nano liquid cone electrospray mass spectrometry ion source system of this invention, combined with a ThermoFisher Q-Exactive mass spectrometer, was used for cell-extracted metabolomics analysis and single-cell metabolomics analysis. The dual-sheath fluid cone ion source system was configured as follows: sample solution was single-cell extract at a flow rate of 0.5 μL / min; inner sheath fluid was 1% formic acid-water solution at a flow rate of 1 μL / min; and outer sheath fluid was acetonitrile at a flow rate of 2.0 μL / min. The spray voltage was set to 5.0 kV, and the high-voltage electric field was conducted through the inner sheath fluid to the three-stage layered embedded coaxial outlet, forming a stable liquid cone to ensure efficient spraying. Mass spectrometry acquisition used positive ion mode, with a scan range of 100–1500 m / z, an S-lens RF voltage of 40, a resolution of 70,000, a maximum injection time of 200 ms, and an automatic gain control (AGC) target value of 5 × 10⁵.

[0072] In terms of data analysis, mass spectrometry was used to acquire the mass-to-charge ratio (m / z) and signal intensity of metabolites, obtaining small molecule metabolite mass spectrometry information at the single-cell level. ThermoXcalibur software was used for peak extraction and characteristic metabolite screening of the raw data. Background signal correction was performed on the mass spectrometry data to ensure accurate reflection of the characteristic peaks of the sample metabolites. Metabolite identification was confirmed based on mass-to-charge ratio and secondary fragmentation information using the HMDB (Human Metabolome Database). Metabolic spectral characteristics were extracted for each cell type, and statistical analysis was performed on the metabolite categories. Pie charts were used to present the proportion of metabolites in the four cell types. Principal component analysis (PCA) was used to explore the differences in metabolic characteristics among cells.

[0073] like Figures 15-18As shown, experimental results demonstrate that the device of this invention successfully detected and matched multiple small molecule metabolites in single cells by searching the HMDB library. Specifically, 151 metabolites were matched in RPMI-8226 cells, 174 metabolites in OCI-Aml-3 cells, 181 metabolites in NCI-H929 cells, and 189 metabolites in THP1 cells. The mass spectrometry signal was clear with good peak intensity, exhibiting the high sensitivity and high signal-to-noise ratio of the dual-sheath liquid cone ion source.

[0074] like Figures 19-22 As shown, the results indicate that lipids and lipid molecules account for more than 60% of the composition in all cell types, while organic acids account for about 12%. However, the proportions of organic heterocyclic compounds, benzene ring compounds, organic oxygen-containing compounds, nucleosides, nucleotides, and their analogues vary, with significant differences between different cell types.

[0075] like Figure 23 As shown, principal component analysis (PCA) revealed that the metabolomics of different cell types were clearly distinguishable in the omics space. The overlap in metabolomics features may be due to similar metabolic pathway activities, such as amino acid metabolism. Both RPMI-8226 and OCI-Aml-3 cells exhibited a high dependence on glutamine, a metabolic characteristic of many rapidly proliferating cells, such as tumor cells. The clear distinction between NCI-H929 and THP1 cells and RPMI-8226 and OCI-Aml-3 cells in the PCA analysis reflects the significant differences in their metabolic characteristics due to variations in cellular function, metabolic needs, and tumor metabolic reprogramming pathways.

[0076] The three-tiered, embedded dual-sheath liquid micro / nano-liquid conical electrospray mass spectrometry ion source system of this invention is an innovative technology that provides an efficient, sensitive, and stable mass spectrometry analysis platform for the field of single-cell metabolomics, with broad application prospects. The study demonstrates the excellent performance of the dual-sheath liquid conical electrospray ion source in single-cell metabolomics analysis, providing technical support for research on tumor heterogeneity, metabolic pathway reprogramming, and disease mechanisms.

[0077] As can be seen from the above embodiments, the three-level layered embedded multifunctional dual-sheath liquid micro / nano-liquid cone electrospray mass spectrometry ion source system provided by this invention not only effectively solves the problems of low ionization efficiency, poor spray stability, and weak anti-contamination ability faced by traditional electrospray ion sources in the analysis of complex samples, but also demonstrates excellent performance in single-cell metabolomics research. Through innovative needle-free design, synergistic effect of dual sheath liquids, optimized high-voltage electric field distribution, and precise fluid dynamics control, this system achieves a significant improvement in mass spectrometry analysis efficiency and applicability, providing strong technical support for complex sample analysis and biomedical research.

[0078] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A dual-sheath liquid micro- nanoelectrospray ion source system, characterized in that, include: A dual-sheath fluid tubing module, comprising a sample quartz capillary, an inner sheath fluid quartz capillary, and an outer sheath fluid stainless steel tube arranged coaxially, wherein the sample quartz capillary is located at the center, the inner sheath fluid quartz capillary wraps around the sample quartz capillary, and the outer sheath fluid stainless steel tube wraps around the inner sheath fluid quartz capillary. The outlet end of the sample quartz capillary, the outlet end of the inner sheath fluid quartz capillary, and the outlet end of the outer sheath fluid stainless steel tube are arranged to form a three-level layered embedded coaxial outlet. An integrated micro-flow pump control module is connected to the dual-sheath liquid pipeline module and is used to deliver sample liquid to the sample quartz capillary, deliver inner sheath liquid to the inner sheath liquid quartz capillary, and deliver outer sheath liquid to the outer sheath liquid stainless steel tube, wherein the outer sheath liquid is a liquid. A high-voltage electric potential loading module is connected to the inner sheath fluid quartz capillary and is used to transmit the high-voltage electric field to the three-stage layered embedded coaxial outlet through the inner sheath fluid. The sample quartz capillary, the inner sheath fluid quartz capillary, and the outer sheath fluid stainless steel tube are configured such that, under the action of the high-voltage electric field, the sample liquid, the inner sheath fluid, and the outer sheath fluid located at the three-stage layered embedded coaxial outlet form a liquid cone to generate charged ions.

2. The dual-sheath liquid micro-nano-electrospray ion source system of claim 1, wherein, The outlet end of the sample quartz capillary is recessed compared to the outlet end of the inner sheath fluid quartz capillary, while the outlet end of the inner sheath fluid quartz capillary protrudes beyond the outlet end of the outer sheath fluid stainless steel tube.

3. The dual-sheath liquid micro-nano-electrospray ion source system of claim 1, wherein, The outlet end of the sample quartz capillary protrudes beyond the outlet end of the inner sheath fluid quartz capillary, while the outlet end of the inner sheath fluid quartz capillary protrudes beyond the outlet end of the outer sheath fluid stainless steel tube.

4. The dual-sheath liquid micro-nano-electrospray ion source system according to any one of claims 1-3, wherein, The dual-sheath fluid pipeline module also includes: a first T-shaped tee and a second T-shaped tee; The sample quartz capillary tube is inserted into the main inlet of the first T-tee and passes sequentially through the main outlet of the first T-tee, the main inlet of the second T-tee, and the main outlet of the second T-tee. The inner sheath fluid quartz capillary encloses the sample quartz capillary, with one end connected to the main pipeline output port of the first T-shaped tee, and the other end passing sequentially through the main pipeline input port and the main pipeline output port of the second T-shaped tee. The outer sheath fluid stainless steel tube encloses the portion of the inner sheath fluid quartz capillary tube that extends out of the main pipeline outlet of the second T-shaped tee, and one end of the capillary tube is connected to the main pipeline outlet of the second T-shaped tee.

5. The dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system according to any one of claims 1-3, characterized in that, The integrated micro-flow pump control module includes: integrated micro-flow pump control module one, integrated micro-flow pump control module two, and integrated micro-flow pump control module three; The integrated micro-flow pump control module one, the integrated micro-flow pump control module two, and the integrated micro-flow pump control module three have the same structure, and each includes: Stepper motor; Couplings; A lead screw and a lead screw nut, wherein the lead screw is connected to the stepper motor via the coupling, and the lead screw nut is disposed on the lead screw; A Luer connector glass syringe includes a plunger and a storage chamber for storing the corresponding sample solution, the inner sheath fluid, or the outer sheath fluid; A miniature linear slide rail and a slider, one end of which clamps the outer shell of the Luer connector glass syringe and is mounted on the miniature linear slide rail, and the other end of which is connected to the lead screw nut; The miniature linear slide rail is also equipped with a fixing block, and the push rod of the Luer connector glass syringe abuts against the fixing block.

6. The dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system according to any one of claims 1-3, characterized in that, The system also includes a high-voltage output conductor and a T-type PEEK tee; The first end of the T-type PEEK tee is connected to the high-voltage potential loading module via the high-voltage output wire, the second end is connected to the inner sheath liquid quartz capillary, and the third end is connected to the integrated micro-flow pump control module.

7. The dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system according to any one of claims 1-3, characterized in that, The inner sheath fluid is an aqueous solution containing volatile organic acids or organic bases; the outer sheath fluid is an organic solvent.

8. The dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system according to claim 7, characterized in that, The flow rate ratio of the sample liquid, the inner sheath liquid, and the outer sheath liquid is 0.5-1:0.5-2:1-10.

9. A method using the dual-sheath liquid micro / nano liquid cone electrospray mass spectrometry ion source system as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: The integrated micro-flow pump control module delivers the sample liquid to the sample quartz capillary, the inner sheath liquid to the inner sheath liquid quartz capillary, and the outer sheath liquid to the outer sheath liquid stainless steel tube based on a preset flow rate ratio. S2: Apply a high-voltage electric field to the inner sheath fluid through the high-voltage electric potential loading module, so that the high-voltage electric field is transmitted to the three-stage layered embedded coaxial outlet through the inner sheath fluid; S3: By transmitting a high-voltage electric field to the three-level layered embedded coaxial outlet, the sample liquid, the inner sheath liquid, and the outer sheath liquid located at the three-level layered embedded coaxial outlet form a liquid cone spray to generate charged ions.

10. The method according to claim 9, characterized in that, The method further includes: The charged ions are guided into a mass spectrometer for analysis.

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