Sample collection and pretreatment ionization device for paper-based spray ionization mass spectrometer

Abstract

The application relates to a sample collection and pretreatment ionization device for a paper-based spray ionization mass spectrometer, which comprises a sampling test paper, an ionization box, a test paper groove arranged in the ionization box, a conductive column arranged at the bottom of the test paper groove, a solvent containing part arranged at the rear side of the ionization box, a capillary groove arranged between the test paper groove and the solvent containing part, a puncturable barrier arranged in the solvent containing part and used for preventing the solvent from flowing from the solvent containing part to the capillary groove in a non-use state, a capillary slidably arranged in the capillary groove, the capillary having an operation end and a puncture end opposite to the operation end, the operation end extending out of the capillary groove, and the puncture end being aligned with the puncturable barrier of the solvent containing part, and the capillary being configured to puncture the puncturable barrier and capillary flow the elution solvent in the solvent containing part to the test paper groove to soak the sampling test paper when the operation end is pushed.

Description

Technical Field

[0001] This invention relates to the field of mass spectrometry analysis technology, and in particular to a sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer. Background Technology

[0002] Paper-based spray ionization is a novel atmospheric pressure ionization technique that enables rapid ionization and mass spectrometry analysis of samples using a paper matrix. The basic operation involves loading the sample onto the surface of a cellulose or hemicellulose paper matrix (such as chromatography paper) with a pointed tip, aligning the tip with the mass spectrometer inlet, and applying a 3–5 kV high voltage to the opposite side of the tip. The high electric field generated at the tip induces the formation of charged droplets carrying analyte ions. Utilizing the capillary action and electrophoretic effect unique to chromatography paper, the analyte desorbs from the matrix and migrates towards the tip, forming a Taylor cone at the tip for ionization, ultimately generating electrospray ions that enter the mass spectrometer.

[0003] The combination of paper-based spray ionization technology and mass spectrometry enables direct sample analysis. The sample only needs to be dropped onto the paper-based material, eliminating the need for complex pretreatment steps. This makes it particularly suitable for rapid screening of complex matrix samples, significantly shortening the detection cycle. However, this technology still has the following shortcomings in practical field testing applications: The pretreatment of solid samples is cumbersome. When the sample being tested is a solid sample (such as drug residues, explosive residues, or trace evidence), it is usually necessary to first collect the sample by wiping with test paper or using a cotton swab, then immerse the test paper or cotton swab with the suspected particles in a solvent for elution, and finally use a pipette or dropper to add the eluent onto the paper base material. This process involves many steps, is highly dependent on manual operation, and is prone to introducing operational errors, affecting detection efficiency and reproducibility.

[0004] Solvent addition relies on manual experience and has poor control precision. To achieve ideal ionization results, an appropriate amount of specialized elution solvent must be precisely added to the sampling test paper to fully wet the paper base material and achieve effective dissolution and ionization of the target analyte. However, improper control of the solvent dosage directly affects signal strength and reproducibility, requires a high level of operator skill, and is not conducive to standardization and rapid on-site use.

[0005] Open ionization structures have poor stability. Existing devices generally use open ionization spaces, which are easily affected by environmental airflow disturbances, leading to unstable ionization processes, large fluctuations in ion signals, and poor repeatability, thus limiting the reliability and accuracy of detection results.

[0006] In summary, although the aforementioned pretreatment steps can reduce matrix interference and improve ionization efficiency to some extent, their cumbersome operation and environmental sensitivity severely limit the widespread application of paper-based spray ionization technology in portable, rapid on-site detection scenarios. As a key ionization accessory for portable mass spectrometers, paper-based spray ionization devices urgently need to achieve mature industrial manufacturing and modular design to support lightweight, portable, and rapid replacement of key components, meeting the requirements for efficient and stable operation in complex environments such as field sites and emergency detection. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, the present invention provides a sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer.

[0008] To achieve the above objectives, the present invention provides a sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer, characterized in that it includes: Sampling test strips; An ionization box includes an ionization box body, a test strip groove on the front side of the ionization box body, the outline of the test strip groove matching the outline of the sampling test strip, a conductive post at the bottom of the test strip groove, and a solvent receiving portion for holding the elution solvent on the rear side of the ionization box body. The test strip groove and the solvent receiving portion are connected by a capillary groove. A puncture-resistant barrier is provided in the solvent receiving portion to prevent the solvent from flowing from the solvent receiving portion to the capillary groove when not in use. A capillary tube is slidably disposed within the capillary groove. The capillary tube has an operating end and a piercing end opposite to the operating end. The operating end extends outside the capillary groove, and the piercing end is aligned with a pierceable barrier in the solvent reservoir. The capillary tube is configured such that when the operating end is pushed, the piercing end pierces the pierceable barrier and capillarily guides the elution solvent in the solvent reservoir into the test strip groove to wet the sampling test strip.

[0009] Preferably, the ionization box includes an ionization box cover, which covers the ionization box body. The ionization box cover is provided with a protective sheet, which is used to protect the puncture-resistant barrier of the solvent container.

[0010] Preferably, a limiting mechanism is provided between the ionization box cover and the ionization box body, the limiting mechanism including a limiting post and a limiting groove that matches the limiting post.

[0011] Preferably, the puncture-resistant barrier includes a puncture-resistant barrier film layer.

[0012] Preferably, the solvent container includes a solvent tank and a solvent box disposed within the solvent tank, wherein the barrier film layer is disposed in at least the portion of the solvent box corresponding to the punctured end.

[0013] Preferably, the outline of the test strip groove and the outline of the sampling test strip are both teardrop-shaped, the teardrop-shaped tip of the sampling test strip is set away from the capillary, and the sharp angle of the teardrop-shaped tip does not exceed 45°.

[0014] Preferably, the piercing end of the capillary is an oblique end.

[0015] Preferably, the bottom of the solvent container is lower than the bottom of the capillary groove, and the lowest point of the inner wall of the capillary is higher than the bottom surface of the solvent in the solvent container.

[0016] Preferably, the bottom of the capillary groove is lower than the bottom of the test paper groove, and the wall thickness of the capillary is less than the height difference between the bottom of the capillary groove and the bottom of the test paper groove.

[0017] Preferably, it also includes an ionization hood, one end of which is connected to the mass spectrometer injection port, and the other end of which is connected to the ionization cell.

[0018] The sample acquisition and pretreatment ionization device for paper-based spray ionization mass spectrometer provided by this invention integrates sample acquisition, elution and ionization functions, and constructs a relatively closed ionization space, which significantly simplifies the on-site sample acquisition and pretreatment process. It not only improves the stability and efficiency of paper-based spray ionization, but also takes into account the mature and reliable industrial and modular production requirements, and has good application prospects and promotion value. Attached Figure Description

[0019] Figure 1 This is a first structural schematic diagram of the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention.

[0020] Figure 2 This is a schematic diagram of the ionization cell body in the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention.

[0021] Figure 3 This is a schematic diagram of the structure of the ionization box cover in the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention.

[0022] Figure 4 This is a schematic diagram of the sampling test paper in the sample collection and pretreatment ionization device of the paper-based spray ionization mass spectrometer of the present invention.

[0023] Figure 5This is a schematic diagram of the capillary structure in the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention.

[0024] Figure 6 This is a top view of the solvent container in the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention.

[0025] Figure 7 This is a high-voltage circuit diagram of the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention.

[0026] Figure 8 This is a schematic diagram of the ionization hood assembly structure of the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention.

[0027] Figure 9 This is a front view of the ionization hood assembly of the sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention during application. Detailed Implementation

[0028] To more clearly describe the technical content of the present invention, the following description is provided in conjunction with specific embodiments.

[0029] like Figures 1 to 6 The image shows a specific embodiment of the sample collection and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to the present invention. The ionization device consists of three parts: a sampling test paper 2, an ionization box 1, and an ionization hood 3.

[0030] The ionization box 1 consists of two parts: an ionization box body 11 and an ionization box cover 12. A test strip groove 111 is provided on the front side of the ionization box body 11. The outline of the test strip groove 111 matches the outline of the sampling test strip 2. The test strip groove 111 can be slightly larger than the sampling test strip 2 to allow the sampling test strip 2 to be placed flat. A conductive post 115 is provided at the bottom of the test strip groove 111, penetrating the test strip groove 111. During analysis, a high voltage of 3-5 kV is applied to the high-voltage conductive post 115 at the bottom of the ionization box body 11. The conductive post 115 is made of a metal with good conductivity, typically brass. The rear side of the ionization box body 11 is provided with a solvent receiving part 113 for accommodating the solvent box 117. The solvent receiving part 113 can be a cuboid solvent tank. The test paper tank 111 and the solvent receiving part 113 are connected by a capillary groove 112. A capillary tube 116 is provided in the capillary groove 112. A puncturable barrier is provided in the solvent receiving part 113 to prevent the solvent from flowing from the solvent receiving part 113 to the capillary groove 112 and the capillary tube 116 when not in use.

[0031] A capillary tube 116 is slidably disposed within the capillary groove 112. The capillary tube 116 has an operating end and a piercing end opposite to the operating end. The operating end extends outside the groove of the capillary tube 116, and the piercing end is aligned with the pierceable barrier. The capillary tube 116 is configured such that when the operating end is pushed, the piercing end pierces the pierceable barrier and capillarily guides the elution solvent in the solvent container into the test paper groove to wet the sampling test paper 2.

[0032] The inner diameter of the capillary groove 112 matches the outer diameter of the capillary 116, and the two fit tightly together. The capillary 116 is confined within the capillary groove 112 due to friction. To ensure that the capillary 116 has a certain advancing distance to generate a certain thrust to pierce the punctureable barrier, the length of the capillary 116 should be greater than the distance h between the test paper groove 111 and the solvent container 113, and preferably not less than 1 cm from h.

[0033] The ionization box includes an ionization box cover 12, which covers the ionization box body 11. The ionization box cover 12 is provided with a protective sheet 122, which protects the puncture-resistant barrier of the solvent container to prevent the capillary tube 116 from slipping out of its groove and puncturing the barrier under strong external force during transportation. When the ionization box cover 12 is fully fitted to the ionization box body, the protective sheet 122 will be inserted tightly into the solvent container. The protective sheet 122 can be connected to the cover using a perforated wire for easy removal during use.

[0034] A limiting mechanism is provided between the ionization box cover 12 and the ionization box body 11. The limiting mechanism includes limiting posts 121 and limiting grooves that match the limiting posts 121. In this embodiment, the six limiting posts 121 of the ionization box cover 12 respectively engage with the six limiting grooves of the ionization box body 11. When the limiting posts 121 fall into the limiting grooves, the ionization box cover 12 and the ionization box body 11 form a complete ionization box.

[0035] The puncture-resistant barrier includes a barrier film layer 1171. The solvent container 113 includes a solvent tank and a solvent box 117 disposed within the solvent tank for containing solvent. The puncture-resistant barrier film layer 1171 is disposed in the portion 1131 of the solvent box 117 corresponding to the puncture end.

[0036] The solvent box 117 can be an independent, movable cuboid box, one side of which is sealed with a layer of polypropylene (PP) film or aluminum-plastic composite film as a puncture-resistant barrier film layer 1171. The solvent box 117 contains a certain amount of elution solvent 1172, for example, methanol:water = 9:1.

[0037] The amount of elution solvent should be sufficient to completely wet the test paper. The dimensions of the solvent tank and solvent container 117 can be designed according to the actual required amount of elution solvent. The ionization box and solvent container 117 can be made of polypropylene or polytetrafluoroethylene.

[0038] The outline of the test strip groove and the outline of the sampling test strip 2 are both teardrop-shaped. The teardrop-shaped tip of the sampling test strip 2 is set away from the capillary tube 116, and the sharp angle of the teardrop-shaped tip does not exceed 45°.

[0039] Sampling test strip 2 can be made of cellulose chromatography paper, with a teardrop shape and a tip angle of less than 30° being optimal. The rounded part is used for wiping and sampling, and the tip is used to generate a spray.

[0040] The piercing end of the capillary 116 is an oblique end and is located within the capillary groove 112. For example, one end of the capillary 116 is round and the other end is oblique, with the oblique end edge preferably flush with the end face of the capillary groove 112. The capillary 116 can be a glass capillary.

[0041] To ensure that the capillary tube 116 can pierce the puncturable barrier during use, the bottom of the solvent container can be slightly lower than the bottom of the capillary groove, and the wall thickness of the solvent box 117 is less than the height difference between the bottom of the solvent container and the bottom of the capillary groove, that is, the lowest point of the inner wall of the capillary tube 116 is higher than the bottom of the inner wall of the solvent box 117.

[0042] To ensure better wetting of the test paper by the elution solvent, the bottom of the capillary groove 112 is lower than the bottom of the test paper groove, and the wall thickness of the capillary 116 is less than the height difference between the bottom of the capillary groove 116 and the bottom of the test paper groove. That is, the horizontal plane of the sampling test paper 2 is slightly higher than the lowest point of the inner wall of the capillary 116, allowing the solvent to be well adsorbed by the test paper at the capillary 116 port and to wet the entire test paper through the capillary action of the test paper fibers themselves.

[0043] like Figures 7 to 9 As shown, one end of the ionization shield 3 is connected to the mass spectrometer inlet 4, and the other end of the ionization shield 3 is connected to the ionization chamber 1. Through the shield-type structural design, the mass spectrometer inlet and the ionization chamber are integrated in the same space, realizing three major functions: high voltage application, ionization chamber fixation, and improved ionization stability.

[0044] The ionization chamber includes an ionization box inlet channel 31 for inserting and fixing the ionization box in a designated position. The channel width L is the same as the width of the front side of the ionization box, and the two fit tightly together. The ionization box has a boss 118. The ionization box is inserted into the channel until the boss of the ionization box abuts against the inlet channel. At this point, the distance between the ionization box and the mass spectrometer injection port no longer changes. A high-voltage power supply is connected to the conductive column of the ionization box via a high-voltage wire 32 and a high-voltage terminal 33 to deliver a stable high voltage to the test strip. The ionization chamber assembly can be made of engineering plastics such as ABS or PC.

[0045] When using the sample collection and pretreatment ionization device of the present invention for paper-based spray ionization mass spectrometer at the drug or explosive detection site, remove the top cover of the ionization box, wipe the suspected substance with the sampling test paper, place the wiped test paper into the test paper trough, and then push the capillary backward. The tip of the capillary pierces the polypropylene film layer, and the solvent in the box enters the test paper trough through the capillary. Under the elution solvent, the sample on the test paper, under the unique capillary action and electrophoresis process of the chromatography paper, causes the analyte to desorb from the matrix and migrate to the tip.

[0046] The high electric field at the tip of the test strip causes sample molecules to form a Taylor cone at the tip, completing ionization, and then entering the mass spectrometer inlet under the influence of the electric field. Specifically, remove the protective sheet from the ionization box cover, replace the ionization box cover, and push the ionization box with the cover closed into the ionization box inlet channel of the ionization shroud assembly until the ionization box protrusion abuts against the ionization shroud assembly. At this point, the distance between the ionization box and the mass spectrometer inlet is fixed. The high-voltage power supply delivers a stable high voltage to the test strip through high-voltage wires and high-voltage terminals connected to the conductive column, and the mass spectrometry analysis is started.

[0047] This invention simplifies the dissolution process and paper-based material wetting process after solid (powder) sample collection. The sampled test paper is placed in the ionization chamber, and simply pushing the capillary in the chamber automatically introduces the elution solvent and effectively wets the test paper. This achieves an integrated design of sample extraction and elution, test paper wetting, and high-voltage ionization. The ionization hood assembly ensures a relatively enclosed ionization space, reducing airflow disturbance to the Taylor cone and interference with the ion transport path, significantly improving signal reproducibility and stability.

[0048] The ionization device of this invention serves as a sample pretreatment and ionization accessory for in-situ mass spectrometers. It adopts an integrated and modular design concept. In addition to the innovative solvent addition method of "sampling - pushing the tube to puncture the membrane - solvent capillary flow - test paper wetting", it also highly integrates functions such as ionization box fixation, high-voltage ionization access, and closed ionization space construction through the ionization hood assembly, which greatly improves the convenience and efficiency of in-situ mass spectrometry detection.

[0049] In this specification, the invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations can be made without departing from the spirit and scope of the invention. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. A sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer, characterized in that, include: Sampling test strips; An ionization box includes an ionization box body, a test strip groove on the front side of the ionization box body, the outline of the test strip groove matching the outline of the sampling test strip, a conductive post at the bottom of the test strip groove, and a solvent receiving portion for holding the elution solvent on the rear side of the ionization box body. The test strip groove and the solvent receiving portion are connected by a capillary groove. A puncture-resistant barrier is provided in the solvent receiving portion to prevent the solvent from flowing from the solvent receiving portion to the capillary groove when not in use. A capillary tube is slidably disposed within the capillary groove. The capillary tube has an operating end and a piercing end opposite to the operating end. The operating end extends outside the capillary groove, and the piercing end is aligned with a pierceable barrier in the solvent reservoir. The capillary tube is configured such that when the operating end is pushed, the piercing end pierces the pierceable barrier and capillarily guides the elution solvent in the solvent reservoir into the test strip groove to wet the sampling test strip.

2. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 1, characterized in that, The ionization box includes an ionization box cover, which covers the ionization box body. The ionization box cover is provided with a protective sheet, which is used to protect the puncture-resistant barrier.

3. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 2, characterized in that, A limiting mechanism is provided between the ionization box cover and the ionization box body. The limiting mechanism includes a limiting post and a limiting groove that matches the limiting post.

4. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 1, characterized in that, The puncture-resistant barrier includes a puncture-resistant barrier film layer.

5. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 4, characterized in that, The solvent container includes a solvent tank and a solvent box disposed within the solvent tank, wherein at least the portion of the solvent box corresponding to the puncture end is provided with the puncture-resistant barrier film layer.

6. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 1, characterized in that, The outline of the test strip groove and the outline of the sampling test strip are both teardrop-shaped. The teardrop-shaped tip of the sampling test strip is set away from the capillary tube, and the sharp angle of the teardrop-shaped tip does not exceed 45°.

7. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 1, characterized in that, The piercing end of the capillary is an oblique end.

8. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 1, characterized in that, The bottom of the solvent container is lower than the bottom of the capillary groove, so that the lowest point of the inner wall of the capillary is higher than the lowest point of the solvent in the solvent container.

9. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 1, characterized in that, The bottom of the capillary groove is lower than the bottom of the test paper groove, and the lowest point of the inner wall of the capillary is higher than the bottom of the solvent.

10. The sample acquisition and pretreatment ionization device for a paper-based spray ionization mass spectrometer according to claim 1, characterized in that, It also includes an ionization shield, one end of which is connected to the mass spectrometer injection port, and the other end of which is connected to the ionization cell.

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