Transmission-type desorption electrospray ionization source

Abstract

The utility model relates to a transmission type desorption electrospray ionization source which comprises a flow injection pump, a capillary electrospray needle, a capillary high-voltage power supply device, a transmission grid mesh, an ion funnel device and an interface electrode, an ionization area is formed between the capillary electrospray needle and the transmission grid mesh, and an ion convergence area is formed between the transmission grid mesh and the interface electrode. The transmission-type desorption electrospray ionization source can realize high-efficiency desorption electrospray ionization of substances difficult to volatilize in the detection process, the sample detection process is simplified, the detection sensitivity of anesthetic drugs in blood is as low as ng [mu] L <-1 >, the transmission-type desorption electrospray ionization source can be connected with an ion mobility spectrometry, and high-efficiency ionization of high-boiling-point polar chemicals difficult to volatilize is realized.

Description

Technical Field

[0001] This invention belongs to the field of analytical chemistry instruments, specifically relating to a transmission-type analytical electrospray ionization source. Background Technology

[0002] Effective combined infusion of sedatives and analgesics during surgery, along with monitoring of blood drug concentrations, is of significant clinical importance for precise anesthesia administration. The research team achieved highly sensitive detection of volatile compounds such as explosives using photoionization thermal desorption ion mobility spectrometry (IMS), but its sensitivity for measuring polar, non-volatile compounds, such as anesthetic drugs in the blood, is not high; there is currently no technology, either domestically or internationally, to achieve bedside measurement of these compounds.

[0003] This invention designs a transmission-type analytical electrospray ionization source to solve the problem of effective ionization of polar, non-volatile compounds. Developing transmission-type analytical electrospray ionization sources is crucial for expanding the application scope of IMS technology. Like traditional electrospray ionization (ESI), transmission-type analytical electrospray ionization produces ions in the form of ionic droplets. Using these droplets as an ionization source for ion mobility spectrometry (IMS) requires complete desolvation of these droplets. IMS identifies compounds based on their mobility; if the ionic droplets are not completely desolvated, their mobility changes, leading to inaccurate IMS identification. Furthermore, the solvent in incompletely desolvated ionic droplets continues to evaporate in the ion mobility tube, causing severe ion clustering and reducing the resolution and sensitivity of IMS. Professor Jiang Jie of Harbin Institute of Technology attempted to use paper spray ionization as an IMS ionization source to detect cocaine in methanol-water, but IMS operates near room temperature and cannot completely desolvate the ionic droplets, resulting in a detection limit of only 2 µg / ml. Using high-temperature gas (above 100 °C) to purge ionic droplets for desolvation is a widely used method in traditional ESI ionization sources. However, like traditional ESI ionization sources, paper spray ionization sources cannot be heated, otherwise the spray solvent will evaporate, causing spraying to stop. Therefore, developing a technology that can achieve complete desolvation of ionic droplets while protecting the electrospray ionization source is key to the successful application of transmission desorption electrospray ionization in IMS.

[0004] This invention will develop desolvation transmission desorption electrospray technology to achieve efficient ionization of non-volatile polar substances, improve the sensitivity of trace substances, and expand the application scenarios of IMS on-site detection. Monitoring the blood concentrations of analgesics and sedatives during surgical anesthesia is crucial for the precise implementation of clinical anesthesia. This invention aims to develop a rapid blood concentration monitoring method for bedside anesthetic drugs. Utilizing a transmission grid as the substrate of the electrospray ionization source, and employing direct Joule thermal desorption with rapid temperature variations to assist in the vaporization of anesthetic drugs, this invention achieves pre-separation and desorption ionization of target substances, providing a new technological means for monitoring bedside anesthetic drug concentrations and ensuring precise anesthesia implementation. Utility Model Content

[0005] To address the problems existing in the prior art, this invention provides a transmission-type analytical electrospray ionization source, which can ionize polar, non-volatile substances while shielding or eliminating the influence of other interfering substances in blood samples on the detection of anesthetic drugs, thereby achieving highly sensitive detection of anesthetic drugs in complex matrices of blood samples.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A transmissive analytical electrospray ionization source includes a flow injection pump, a capillary electrospray needle, a capillary high-voltage power supply device, a transmission grid, an ion funnel device, and an interface electrode.

[0008] The ion funnel device consists of several electrodes with through holes in the center. These electrodes are arranged in parallel, equally spaced rows with coaxial through holes. The electrodes are either circular or square ring-shaped, and are separated by insulating rings with an inner diameter of 1-18 mm and a thickness of 1-2 mm. The ion funnel device has 4-20 electrodes. Each electrode has a circular through hole in the center, with a diameter of 1-20 mm, gradually decreasing in diameter from left to right. The electrodes are fixed to an insulating PEEK post. The interface electrode is a metal sheet electrode with a through hole in the center, connected to the rightmost electrode of the ion funnel device via an insulating ring with a through hole in the center. The ion funnel device and the interface electrode are coaxial with the central through hole. An ionization source exhaust outlet is located on the upper wall of the ion funnel device near the interface electrode. This outlet is connected to the atmosphere via a pressure gauge and an exhaust pump installed on a connecting pipe.

[0009] On the left side of the ion funnel device, a transmission grid and a mounting bracket for fixing the capillary electrospray needle are arranged sequentially. The mounting bracket is placed on a three-dimensional displacement platform. The transmission grid is located between the capillary electrospray needle and the ion funnel device, positioned between two parallel PEEK sheets on the mounting bracket. The capillary electrospray needle includes a capillary tube body with an axial through hole and a spray tip. The capillary electrospray needle body is fixed horizontally on the mounting bracket, and the spray tip of the capillary electrospray needle points towards the transmission grid and coincides with the axis of the ion funnel device and the interface electrode.

[0010] One end of the capillary tube of the capillary electrospray needle is connected to the inlet of the spray tip, and the other end is connected to the syringe of the flow injection pump.

[0011] An ionization region is formed between the capillary electrospray needle and the transmission grid, and an ion aggregation region is formed between the transmission grid and the interface electrode.

[0012] A copper foil is wound around the spray tip of a capillary electrospray needle. The copper foil is connected to a high-voltage power supply device for the capillary tube, and the voltage applied to the copper foil is greater than or equal to 2000 V. The transmission grid, ion funnel device, and interface electrode are all directly connected to an external power source.

[0013] Different axial voltages are applied to the spray tip, transmission grid, ion funnel device, and interface electrode of the capillary electrospray needle in descending order of voltage.

[0014] The distance between the spray tip of the capillary electrospray needle and the transmission grid is 1-2 mm, the distance between the transmission grid and the ion funnel device is 6-8 mm, and the distance between the tip of the capillary electrospray needle and the ion funnel device is 7-10 mm.

[0015] The matrix material of the transmission grid is a high-temperature resistant, corrosion resistant, thermally conductive, and non-deformable iron-chromium-aluminum or nickel-chromium alloy. The size of the transmission grid is 1 cm*1 cm, the thickness is 1-1.5 mm, the aperture of the wire is about 300 μm, the wire diameter of the grid is about 200 μm, and the scanning speed of the transmission grid is 100-500 μm / s.

[0016] The capillary tube of the capillary electrospray needle has an outer diameter of 1.5-2 mm, an inner diameter of 0.8-1.5 mm, and a length of 10-15 cm. The nozzle diameter of the spray tip of the capillary electrospray needle is about 0.5-1 μm.

[0017] The central through-hole of the interface electrode is connected to the inlet of the ion migration tube.

[0018] Compared with existing technologies, the advantages of this invention are as follows: It uses a transmissive grid as the substrate for blood samples, which is replaceable, avoids cross-interference, improves the repeatability of analysis, eliminates the need for complex sample pretreatment, and simplifies the sample processing procedure. Furthermore, it employs rapid variable-temperature Joule thermal desorption technology, which enables the rapid vaporization equilibrium of components with different boiling points, achieves primary pre-separation, increases the concentration of gaseous samples per unit time, and increases the vaporization rate of highly volatile substances such as methanol through solvent-assisted vaporization, thereby improving vaporization efficiency, shortening the single analysis time, and enabling highly sensitive online detection of anesthetic drugs in blood at the bedside. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a transmission-type analytical electrospray ionization source. In the diagram, 1 is a flow injection pump, 2 is a capillary electrospray needle, 3 is a high-voltage power supply device for the capillary electrospray needle, 4 is a transmission grid, 5 is an ion funnel device, 6 is an interface electrode, 7 is the ionization source exhaust outlet, 8 is a pressure gauge, 9 is an exhaust pump, 10 is the ionization region, and 11 is the ion aggregation region. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. Example

[0021] like Figure 1 As shown, this utility model provides a transmission-type analytical electrospray ionization source, including a flow injection pump 1, a capillary electrospray needle 2, a capillary high-voltage power supply device 3, a transmission grid 4, an ion funnel device 5, and an interface electrode 6.

[0022] The ion funnel device 5 consists of six electrodes with through holes in the center. The electrodes are arranged in parallel, equally spaced, and with the through holes coaxial. The electrodes are circular, and each electrode is separated by five 2mm thick insulating rings with inner diameters of 16mm, 14mm, 12mm, 10mm, and 8mm, respectively. The six electrodes of the ion funnel device 5 have circular through holes in the center. From left to right, the diameters of the through holes in the center of the electrodes are 18mm, 16mm, 14mm, 12mm, 10mm, and 8mm, respectively. The electrodes and insulating rings are fixed to an insulating PEEK column.

[0023] The interface electrode 6 is a metal sheet electrode with a through hole in the center, and is connected to the rightmost electrode of the ion funnel device 5 through an insulating ring with a through hole in the center (the diameter of the through hole is 8 mm); the ion funnel device 5 is coaxial with the through hole in the center of the interface electrode 6; the diameter of the through hole in the center of the interface electrode 6 is 2 mm.

[0024] An ionization source exhaust outlet 7 is provided on the upper wall of the ion funnel device 5 near the interface electrode 6. The ionization source exhaust outlet 7 is connected to the atmosphere through a pressure gauge 8 and an exhaust pump 9 installed on the connecting pipeline.

[0025] On the left side of the ion funnel device 5, a transmission grid 4 and a fixing frame for fixing the capillary electrospray needle 2 are arranged sequentially. The fixing frame is placed on a three-dimensional displacement platform. The transmission grid 4 is located between the capillary electrospray needle 2 and the ion funnel device 5, and is placed between two parallel PEEK sheets on the fixing frame. The capillary electrospray needle 2 includes a capillary tube body with an axial through hole and a spray tip. The tube body of the capillary electrospray needle 2 is fixed to the fixing frame in a horizontal direction. The spray tip of the capillary electrospray needle 2 points towards the transmission grid and coincides with the axis of the ion funnel device 5 and the interface electrode 6.

[0026] One end of the capillary tube of the capillary electrospray needle 2 is connected to the inlet of the spray tip, and the other end is connected to the syringe of the flow injection pump 1. The capillary electrospray needle 2 is made of borosilicate glass tube, the length of the capillary tube is 10cm, and the inner diameter of the spray tip of the capillary electrospray needle 2 is 0.5 μm.

[0027] A copper foil is wound around the spray tip of the capillary electrospray needle 2. The copper foil is connected to the capillary high-voltage power supply device 3. The voltage applied to the copper foil is 2000 V. The transmission grid 4, the ion funnel device 5, and the interface electrode 6 are all directly connected to an external power source. The axial voltages applied to the spray tip, transmission grid 4, ion funnel device 5, and interface electrode 6 in descending order of voltage are 3500 V, 1000 V, 600 V, and 100 V, respectively.

[0028] An ionization region 10 is formed between the capillary electrospray needle 2 and the transmission grid 4, and an ion aggregation region 11 is formed between the transmission grid 4 and the interface electrode 6.

[0029] The distance between the spray tip of the capillary electrospray needle 2 and the transmission grid 4 is 2 mm, the distance between the transmission grid 4 and the ion funnel device 5 is 8 mm, and the distance between the tip of the capillary electrospray needle 2 and the ion funnel device 5 is 10 mm.

[0030] The matrix material of the transmission grid 4 is a high-temperature resistant, corrosion resistant, fast thermally conductive and non-deformable iron-chromium-aluminum alloy. The size of the transmission grid 4 is 1 cm*1 cm, the thickness is 1.5 mm, the aperture of the wire diameter (i.e. the gap) is about 300 μm, the wire diameter of the grid is about 200 μm, and the scanning speed of the transmission grid is 100-500 μm / s.

[0031] The central through-hole of interface electrode 6 is connected to the inlet of the ion migration tube.

Claims

1. A transmission-type analytical electrospray ionization source, characterized in that: It includes a flow injection pump (1), a capillary electrospray needle (2), a capillary high-voltage power supply device (3), a transmission grid (4), an ion funnel device (5), and an interface electrode (6). The ion funnel device (5) comprises several electrodes with through holes in the center. These electrodes are arranged in parallel, equally spaced sections, with the through holes coaxially aligned. The electrodes are either circular or square-ring shaped, and are separated by insulating rings with an inner diameter of 1-18 mm and a thickness of 1-2 mm. The ion funnel device (5) has 4-20 electrodes. Each electrode in the ion funnel device (5) has a circular through hole in the center, with a diameter of 1-20 mm. mm, and the diameter of the through hole in the middle of the electrode gradually decreases from left to right. The electrode is fixed on an insulating PEEK column. The interface electrode (6) is a metal sheet electrode with a through hole in the center, and is connected to the rightmost electrode of the ion funnel device (5) through an insulating ring with a through hole in the center. The ion funnel device (5) and the central through hole of the interface electrode (6) are coaxial. An ionization source exhaust outlet (7) is provided on the upper wall of the ion funnel device (5) near the interface electrode (6). The ionization source exhaust outlet (7) is connected to the atmosphere through a pressure gauge (8) and an exhaust pump (9) on the connecting pipeline. On the left side of the ion funnel device (5), a transmission grid (4) and a fixing frame for fixing the capillary electrospray needle (2) are arranged in sequence. The fixing frame is placed on a three-dimensional displacement platform. The transmission grid (4) is located between the capillary electrospray needle (2) and the ion funnel device (5) and is placed between two parallel PEEK sheets on the fixing frame. The capillary electrospray needle (2) includes a capillary tube with an axial through hole and a spray tip. The tube of the capillary electrospray needle (2) is fixed to the fixing frame in a horizontal direction. The spray tip of the capillary electrospray needle (2) points to the transmission grid and coincides with the axis of the ion funnel device (5) and the interface electrode (6). One end of the capillary tube of the capillary electrospray needle (2) is connected to the inlet of the spray tip, and the other end is connected to the syringe of the flow injection pump (1). An ionization region (10) is formed between the capillary electrospray needle (2) and the transmission grid (4), and an ion aggregation region (11) is formed between the transmission grid (4) and the interface electrode (6).

2. The transmission-type analytical electrospray ionization source according to claim 1, characterized in that: A copper foil is wound around the spray tip of the capillary electrospray needle (2). The copper foil is connected to the capillary high-voltage power supply device (3). The voltage applied to the copper foil is greater than or equal to 2000 V. The transmission grid (4), the ion funnel device (5), and the interface electrode (6) are all directly connected to an external power source. Different axial voltages are applied to the spray tip, transmission grid (4), ion funnel device (5), and interface electrode (6) of the capillary electrospray needle (2) in descending order.

3. The transmission-type analytical electrospray ionization source according to claim 1, characterized in that: The distance between the spray tip of the capillary electrospray needle (2) and the transmission grid (4) is 1-2 mm, the distance between the transmission grid (4) and the ion funnel device (5) is 6-8 mm, and the distance between the tip of the capillary electrospray needle (2) and the ion funnel device (5) is 7-10 mm.

4. The transmission-type analytical electrospray ionization source according to claim 1, characterized in that: The matrix material of the transmission grid (4) is a high-temperature resistant, corrosion resistant, fast thermally conductive and not easily deformed iron-chromium-aluminum or nickel-chromium alloy. The size of the transmission grid (4) is 1 cm*1 cm, the thickness is 1-1.5 mm, the aperture of the wire diameter is 300 μm, the wire diameter of the grid is 200 μm, and the scanning speed of the transmission grid is 100-500 μm / s.

5. The transmission-type analytical electrospray ionization source according to claim 1, characterized in that: The capillary tube of the capillary electrospray needle (2) has an outer diameter of 1.5-2 mm, an inner diameter of 0.8-1.5 mm, and a length of 10-15 cm. The nozzle diameter of the spray tip of the capillary electrospray needle (2) is 0.5-1 μm.

6. The transmission-type analytical electrospray ionization source according to claim 1, characterized in that: The central through hole of the interface electrode (6) is connected to the inlet of the ion migration tube.

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