Thermal desorption sampling ion source with separation function

Abstract

The invention discloses a thermal desorption sample injection ion source with a separation function, which comprises an ionization cavity, and the top end of the ionization cavity is detachably connected with a heat insulation pad; the heating cavity is fixed to the top end of the heat insulation pad, and a mounting base is mounted at the bottom in the heating cavity; according to the sample injection system, a heating cavity comprises a sample injection unit installed at the top end of the heating cavity, a sample injection pipe is fixedly connected to an installation base, and the sample injection unit is communicated with the sample injection pipe through a sample separation column; the heating system is mounted on the mounting seat; the ionization unit is vertically fixed on one side wall of the ionization cavity, and the ionization unit and the sample feeding pipe are vertically arranged; the detection unit is vertically and fixedly connected to the other side wall of the ionization cavity; a waste liquid opening is formed in the bottom of the ionization cavity. According to the invention, the ionization competition of the target compound of the atmospheric pressure ionization source can be greatly reduced, the sensitivity and the quantitative stability are improved, and more accurate rapid detection is realized.

Description

Technical Field

[0001] The invention relates to the field of subatmospheric pressure ion sources, in particular to a thermal analysis sampling ion source with a separation function. Background Art

[0002] When conducting a thermal desorption electrospray mass spectrometry experiment, the sample to be tested needs to be ionized and the generated ions enter the mass spectrometer for detection. Traditional gas chromatography-mass spectrometers and liquid chromatography-mass spectrometers usually take several hours to analyze once because they require complex sample preparation and gas chromatography or liquid chromatography separation. They are also large in size and are not suitable for laboratory use.

[0003] Atmospheric pressure ionization (API) is a technique for sample ionization under atmospheric pressure, allowing samples to enter the mass spectrometer directly for analysis under normal pressure, providing a possibility for rapid on-site detection. At present, the ionization source can be used for rapid analysis of on-site samples, and one analysis generally takes only tens of seconds. Typical atmospheric pressure ionization sources include analysis electrospray ionization (DESI), direct analysis in real time (DART), thermal analysis atmospheric pressure chemical ionization (TD-APCI), etc. However, these ionization sources usually do not have separation function. After ionization of the ion source, a large number of ions are generated at the same time, and multiple components are ionized at the same time, which easily causes ionization competition between components, affecting the detection of low-abundance target compounds. Since the detection content of target substances in clinical drugs, biological samples and sewage is usually very low, the developed portable mass spectrometers often have a high probability of false positives and false negatives when facing low concentration detection targets.

[0004] In response to this, Bruker developed a GC-APCI-MS with separation function designed for laboratory mass spectrometers. The carrier gas mode adopts the conventional gas phase mode, but it still has problems such as large size, long separation time and high power consumption.

[0005] Based on the above technical problems, the present invention provides a thermal analysis injection ion source with separation function. Summary of the invention

[0006] The purpose of the present invention is to provide a thermal analysis sample introduction ion source with separation function to solve the problems existing in the prior art.

[0007] To achieve the above object, the present invention provides the following solution: The present invention provides a thermal desorption injection ion source with separation function, comprising:

[0008] An ionization chamber, wherein a heat insulating pad is detachably connected to the top of the ionization chamber;

[0009] A heating cavity, wherein the heating cavity is fixed to the top of the thermal insulation pad, and a mounting seat is installed at the bottom of the heating cavity;

[0010] The sample injection system, the heating chamber comprises a sample injection unit mounted on the top of the heating chamber, the mounting seat is fixedly connected with a sample injection tube, the sample injection tube passes through the heating chamber, the thermal insulation pad and extends into the ionization chamber, and the sample injection unit is connected to the sample injection tube through a sample separation column;

[0011] A heating system, wherein the heating system is mounted on the mounting base;

[0012] An ionization unit, wherein the ionization unit is vertically fixed on one side wall of the ionization chamber and is vertically arranged between the ionization unit and the sample injection tube;

[0013] A detection unit, wherein the detection unit is vertically fixedly connected to the other side wall of the ionization chamber, and the detection unit and the ionization unit are correspondingly arranged;

[0014] Wherein, a waste liquid outlet is provided at the bottom of the ionization chamber, and an ionization region is formed between the ionization unit, the detection unit and the sample injection tube.

[0015] According to the thermal desorption ion source with separation function provided by the present invention, the injection unit includes a fixing seat fixedly connected to the top of the heating chamber, a connecting tube is vertically fixedly connected to the fixing seat, a filter assembly is installed on the top of the connecting tube, a glass liner is fixedly connected to the bottom end of the connecting tube, and the glass liner is filled with filter material, an injection heating device is installed on the outer wall of the connecting tube, the injection heating device is fixed on the fixing seat, and a solvent injection tube and an air inlet tube are fixedly connected to the side wall of the top end of the connecting tube.

[0016] According to the thermal desorption ion source with separation function provided by the present invention, a sealing ring is arranged between the thermal insulation pad and the heating cavity.

[0017] According to the thermal decomposition sample injection ion source with separation function provided by the present invention, the sample separation column is a capillary tube, and both ends of the capillary tube are fixedly connected with the glass liner tube and the injection tube respectively.

[0018] According to the thermal decomposition ion source with separation function provided by the present invention, the top of the injection tube and both ends of the glass liner are detachably connected with sealing connectors, and the two ends of the capillary are fixedly connected to the two sealing connectors.

[0019] According to the thermal desorption ion source with separation function provided by the present invention, the heating system includes a heating rod and a temperature measuring rod, and the heating rod and the temperature measuring rod are both fixedly connected to the mounting seat.

[0020] According to the thermal desorption ion source with separation function provided by the present invention, the filter assembly includes a spacer and a fixing nut, the spacer is lined on the top end of the connecting tube, the fixing nut is threadedly connected to the top end of the connecting tube, a through hole is opened in the middle position of the fixing nut, and the spacer is arranged between the fixing nut and the connecting tube.

[0021] According to the thermal desorption sampling ion source with separation function provided by the present invention, the filter material includes quartz wool balls, and the quartz wool balls are filled in the glass liner.

[0022] According to the thermal desorption ion source with separation function provided by the present invention, the ionization chamber is made of metal, the thermal insulation pad is made of ceramic, and the thermal insulation pad is fixed to the top of the ionization chamber by fixing bolts.

[0023] The present invention discloses the following technical effects:

[0024] The present invention introduces a sample separation column of a certain length between the injection unit and the injection tube. Since different components in the sample have different distribution coefficients between the stationary phase and the mobile phase, their movement speeds in the sample separation column will also be different. The component with a smaller distribution coefficient has a higher concentration in the mobile phase, so it moves faster; the component with a larger distribution coefficient has a higher concentration in the stationary phase and moves slower, thus achieving separation. Unlike traditional ionization sources, this patent uses air as a carrier gas, which ensures its sensitivity and detection speed while realizing an integrated and miniaturized design, so as to achieve rapid on-site detection.

[0025] The present invention adds a sample separation column between the injection unit and the injection tube. The mobile phase drives the sample molecules to pass through the sample separation column for rapid separation and detection, which can greatly reduce the ionization competition of the target compound of the atmospheric pressure ionization source, improve the sensitivity and quantitative stability, and achieve more accurate rapid detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the structure of the thermal analysis sample introduction ion source with separation function of the present invention.

[0028] Among them, 1. septum; 2. fixing nut; 3. solvent injection tube; 4. air inlet pipe; 5. sample injection heating device; 6. glass liner; 7. quartz wool ball; 8. sealing connector; 9. capillary; 10. heating chamber; 11. temperature measuring rod; 12. heating rod; 13. insulation pad; 14. sealing ring; 15. ionization unit; 16. detection unit; 17. ionization chamber; 18. ionization area; 19. waste liquid port. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Reference Figure 1 The present invention provides a thermal desorption ion source with separation function, comprising:

[0032] An ionization chamber 17, a thermal insulation pad 13 is detachably connected to the top of the ionization chamber 17;

[0033] A heating cavity 10, wherein the heating cavity 10 is fixed to the top of the thermal insulation pad 13, and a mounting seat is installed at the bottom of the heating cavity 10;

[0034] The sample injection system, the heating chamber 10 includes a sample injection unit installed at the top of the heating chamber 10, the mounting seat is fixedly connected with a sample injection tube, the sample injection tube passes through the heating chamber 10, the thermal insulation pad 13 and extends into the ionization chamber 17, and the sample injection unit is connected to the sample injection tube through a sample separation column;

[0035] A heating system, wherein the heating system is mounted on the mounting base;

[0036] An ionization unit 15, wherein the ionization unit 15 is vertically fixed on one side wall of the ionization chamber 17, and is vertically arranged between the ionization unit 15 and the sample injection tube;

[0037] A detection unit 16, wherein the detection unit 16 is vertically fixedly connected to the other side wall of the ionization chamber 17, and the detection unit 16 is correspondingly arranged between the ionization unit 15;

[0038] A waste liquid port 19 is provided at the bottom of the ionization chamber 17 , and an ionization region 18 is formed between the ionization unit 15 , the detection unit 16 , and the sample injection tube.

[0039] The present invention introduces a sample separation column of a certain length between the injection unit and the injection tube. Since different components in the sample have different distribution coefficients between the stationary phase and the mobile phase, their movement speeds in the sample separation column will also be different. The component with a smaller distribution coefficient has a higher concentration in the mobile phase, so it moves faster; the component with a larger distribution coefficient has a higher concentration in the stationary phase and moves slower, thus achieving separation. Unlike traditional ionization sources, this patent uses air as a carrier gas, which ensures its sensitivity and detection speed while realizing an integrated and miniaturized design, so as to achieve rapid on-site detection.

[0040] The present invention adds a sample separation column between the injection unit and the injection tube. The mobile phase drives the sample molecules to pass through the sample separation column for rapid separation and detection, which can greatly reduce the ionization competition of the target compound of the atmospheric pressure ionization source, improve the sensitivity and quantitative stability, and achieve more accurate rapid detection.

[0041] A further optimized solution is that the sample injection unit includes a fixed seat fixedly connected to the top of the heating chamber 10, a connecting tube is vertically fixedly connected to the fixed seat, a filter assembly is installed at the top of the connecting tube, a glass liner 6 is fixedly connected to the bottom end of the connecting tube, and the glass liner 6 is filled with filter material, an injection heating device 5 is installed on the outer wall of the connecting tube, the injection heating device 5 is fixed on the fixed seat, and a solvent injection tube 3 and an air inlet tube 4 are fixedly connected to the side wall of the top end of the connecting tube.

[0042] According to a further optimized solution, a sealing ring 14 is provided between the thermal insulation pad 13 and the heating cavity 10 .

[0043] According to a further optimized solution, the sample separation column is a capillary tube 9, and both ends of the capillary tube 9 are fixedly connected to the glass liner tube 6 and the sample injection tube, respectively.

[0044] According to a further optimized solution, the top of the injection tube and both ends of the glass liner 6 are detachably connected with sealing connectors 8 , and both ends of the capillary tube 9 are fixedly connected to the two sealing connectors 8 .

[0045] According to a further optimized solution, the heating system comprises a heating rod 12 and a temperature measuring rod 11, and the heating rod 12 and the temperature measuring rod 11 are both fixedly connected to the mounting base.

[0046] A further optimized solution is that the filter assembly includes a spacer 1 and a fixing nut 2, the spacer 1 is lined on the top of the connecting tube, the fixing nut 2 is threadedly connected to the top of the connecting tube, a through hole is opened in the middle position of the fixing nut 2, and the spacer 1 is arranged between the fixing nut 2 and the connecting tube.

[0047] According to a further optimized solution, the filter material includes quartz wool balls 7 , and the quartz wool balls 7 are filled in the glass liner 6 .

[0048] According to a further optimization scheme, the ionization chamber 17 is made of metal, the thermal insulation pad 13 is made of ceramic, and the thermal insulation pad 13 is fixed to the top of the ionization chamber 17 by fixing bolts.

[0049] During operation, the air with organic matter removed by activated carbon filter is used as carrier gas, and the carrier gas is controlled by flow rate control unit (damping or electronic flow controller EFC or electronic pressure controller EPC, flow rate control is within 0-1000ml / min). The heating chamber 10 and the injector are heated to a suitable range by heating rod 12, and the waste liquid pump is connected on the waste liquid port 19, the solvent injection pipe 3 is connected to the injection pump, and the air inlet pipe 4 is connected to the device, and then the air inlet device, the waste liquid pump and the injection pump are opened successively, and the solvent, the carrier gas experimental flow rate and the waste liquid pump pumping speed are set respectively. The corona needle is applied with high pressure by mass spectrometer setting, and the mass spectrometer control detection unit 16 is turned on and operated. At this time, it can be observed that the mass spectrum generates ionization signals, and the mass spectrum collected is electrical noise. So far, the sample injection needle can be prepared to extract a certain volume of sample, and the spacer 1 is inserted into the connecting pipe through the through hole on the solid nut, and the heating device heats the sample, and the sample and the injected solvent are gasified at high temperature to form gas phase molecules. Under the effect of the carrier gas flow of the air inlet device, the sample gas phase molecules enter the capillary 9 through the glass liner 6, and inside the capillary 9, due to the chromatographic principle, different components after the separation of the complex sample are realized, and enter the ionization chamber 17 body in chronological order, and the corona needle discharge of the ionization unit 15 makes the sample to be tested generate gas phase ions, and the gas phase ions to be tested are rapidly sucked in under the high vacuum effect of the detection unit 16, and the sample peak detected can be observed at the mass spectrometer. The sample detection time increases with the increase of the sample concentration. When the detection signal shows that the sample peak height in the mass spectrum is consistent with the background ionization signal when there is no sample injection, the experiment can be ended and the detection unit 16 can be stopped. So far, the next injection can be directly carried out, if the next injection is not needed, the injection solvent flow rate and the guide gas flow rate are increased, and cleaning is completed rapidly. The ionization source mode under this injection is not only used for the chemical ionization source, but also can be used in other ion sources such as ESI, DBDI, DART, EESI, GD, laser, other external ion sources such as single photon ionization.

[0050] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0051] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A thermal desorption ion source with separation function, characterized in that: include: An ionization chamber (17), wherein a heat insulation pad (13) is detachably connected to the top of the ionization chamber (17); A heating cavity (10), wherein the heating cavity (10) is fixed to the top of the thermal insulation pad (13), and a mounting seat is installed at the bottom of the heating cavity (10); A sample injection system, wherein the heating chamber (10) comprises a sample injection unit mounted on the top of the heating chamber (10), a sample injection tube is fixedly connected to the mounting seat, the sample injection tube passes through the heating chamber (10), the heat insulation pad (13) and extends into the ionization chamber (17), and the sample injection unit and the sample injection tube are connected via a sample separation column; A heating system, wherein the heating system is mounted on the mounting base; An ionization unit (15), wherein the ionization unit (15) is vertically fixed on one side wall of the ionization chamber (17), and is vertically arranged between the ionization unit (15) and the sample injection tube; A detection unit (16), the detection unit (16) being vertically fixedly connected to the other side wall of the ionization chamber (17), and being arranged correspondingly between the detection unit (16) and the ionization unit (15); A waste liquid outlet (19) is provided at the bottom of the ionization chamber (17), and an ionization region (18) is formed between the ionization unit (15), the detection unit (16), and the sample injection tube.

2. A thermal desorption ion source with separation function according to claim 1, characterized in that: The sample injection unit comprises a fixing seat fixedly connected to the top of the heating chamber (10), a connecting pipe being vertically fixedly connected to the fixing seat, a filter assembly being installed at the top of the connecting pipe, a glass liner (6) being fixedly connected to the bottom of the connecting pipe, the glass liner (6) being filled with filter material, a sample injection heating device (5) being installed on the outer wall of the connecting pipe, the sample injection heating device (5) being fixed on the fixing seat, and a solvent injection pipe (3) and an air inlet pipe (4) being fixedly connected to the side wall at the top of the connecting pipe.

3. The thermal desorption ion source with separation function according to claim 1, characterized in that: A sealing ring (14) is provided between the thermal insulation pad (13) and the heating cavity (10).

4. The thermal desorption ion source with separation function according to claim 2, characterized in that: The sample separation column is a capillary tube (9), and both ends of the capillary tube (9) are fixedly connected to the glass liner tube (6) and the sample injection tube respectively.

5. The thermal desorption ion source with separation function according to claim 4, characterized in that: The top end of the injection tube and the two ends of the glass liner (6) are respectively detachably connected with sealing connectors (8), and the two ends of the capillary tube (9) are respectively fixedly connected to the two sealing connectors (8).

6. The thermal desorption ion source with separation function according to claim 1, characterized in that: The heating system comprises a heating rod (12) and a temperature measuring rod (11), and the heating rod (12) and the temperature measuring rod (11) are both fixedly connected to the mounting seat.

7. The thermal desorption ion source with separation function according to claim 2, characterized in that: The filter assembly comprises a spacer (1) and a fixing nut (2), wherein the spacer (1) is cushioned at the top end of the connecting tube, the fixing nut (2) is threadedly connected to the top end of the connecting tube, a through hole is provided at the middle position of the fixing nut (2), and the spacer (1) is arranged between the fixing nut (2) and the connecting tube.

8. The thermal desorption ion source with separation function according to claim 2, characterized in that: The filter material comprises quartz wool balls (7), and the quartz wool balls (7) are filled in the glass liner (6).

9. The thermal desorption ion source with separation function according to claim 1, characterized in that: The ionization chamber (17) is made of metal, the thermal insulation pad (13) is made of ceramic, and the thermal insulation pad (13) is fixed to the top of the ionization chamber (17) by means of fixing bolts.

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