Thermal desorption sampling ion source with separation function

Abstract

The application discloses a pyrolysis sampling ion source with a separation function, which comprises an ionization cavity, a heat insulation pad detachably connected to the top end of the ionization cavity, a heating cavity body fixed at the top end of the heat insulation pad, a mounting seat installed at the bottom in the heating cavity body, a sampling system, the heating cavity body comprising a sampling unit installed at the top end of the heating cavity body, a sampling tube fixedly connected to the mounting seat, the sampling unit and the sampling tube being communicated through a sample separation column, a heating system installed on the mounting seat, an ionization unit vertically fixed on one side wall of the ionization cavity and vertically arranged between the ionization unit and the sampling tube, a detection unit vertically fixedly connected to the other side wall of the ionization cavity, and a waste liquid port formed in the bottom of the ionization cavity. The application can greatly reduce the ionization competition of target compounds of an atmospheric pressure ionization source, improve the sensitivity and quantitative stability, and realize more accurate and rapid detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sub-atmospheric pressure ion source, in particular to a thermal desorption sampling ion source with separation function. BACKGROUND

[0002] In the experiment of thermal desorption electrospray mass spectrometry, the sample to be tested needs to be ionized, and the generated ions enter the mass spectrometer for detection. The traditional gas chromatography-mass spectrometer and liquid chromatography-mass spectrometer need to go through complex sample preparation and gas chromatography or liquid chromatography separation, and one analysis usually takes several hours, and the volume is large, suitable for laboratory use.

[0003] Atmospheric pressure ionization source (Atmospheric Pressure Ionization, API) is a technology for ionizing samples under atmospheric pressure, allowing samples to be directly introduced into a mass spectrometer for analysis, providing a possibility for on-site rapid detection. Currently, this ionization source can be used for rapid analysis of on-site samples, and one analysis generally only takes a few tens of seconds. Typical atmospheric pressure ionization sources include desorption electrospray ionization source (Desorption Electrospray Ionization, DESI), direct analysis in real time ionization source (Direct Analysis in Real Time, DART), thermal desorption atmospheric pressure chemical ionization source (Thermal Desorption Atmospheric Pressure Chemical Ionization, TD-APCI), etc. However, these ionization sources generally do not have separation function, and a large number of ions are generated after ionization of the ion source, and multiple components are ionized at the same time, which can easily cause ionization competition between substances, 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 spectrometer often has high probability of false positives and false negatives when detecting low-concentration detection targets.

[0004] To this end, Bruker has developed a GC-APCI-MS with separation function for laboratory mass spectrometers, and the carrier gas mode adopts the conventional gas phase mode, but it still has the problems of large volume, long separation time and high power consumption.

[0005] Based on the above technical problems, the present application provides a thermal desorption sampling ion source with separation function. SUMMARY

[0006] The purpose of the present application is to provide a thermal desorption sampling ion source with separation function to solve the problems existing in the prior art.

[0007] To achieve the above object, the present application provides the following scheme: the present application provides a thermal desorption sampling ion source with separation function, comprising:

[0008] An ionization cavity, a heat insulation pad is detachably connected to the top end of the ionization cavity;

[0009] A heating cavity, the heating cavity is fixed at the top end of the heat insulation pad, and a mounting seat is mounted at the bottom of the heating cavity;

[0010] A sampling system, the heating cavity comprises a sampling unit mounted at the top end of the heating cavity, a sampling tube is fixedly connected to the mounting seat, the sampling tube passes through the heating cavity, the heat insulation pad and extends into the ionization cavity, and the sampling unit and the sampling tube are communicated through a sample separation column;

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

[0012] An ionization unit, the ionization unit is vertically fixed on one side wall of the ionization cavity, and the ionization unit and the sampling tube are vertically arranged;

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

[0014] Wherein, the bottom of the ionization cavity is provided with a waste liquid port, and the ionization unit, the detection unit and the sampling tube form an ionization area.

[0015] According to the thermal desorption sampling ion source with separation function provided by the present application, the sampling unit comprises a fixed seat fixedly connected to the top end of the heating cavity, a connecting pipe is vertically fixedly connected to the fixed seat, a filter assembly is mounted at the top end of the connecting pipe, a glass lining pipe is fixedly connected to the bottom end of the connecting pipe, the glass lining pipe is filled with filter material, a sampling heating device is mounted on the outer wall of the connecting pipe, the sampling heating device is fixed on the fixed seat, and a solvent injection pipe and an air inlet pipe are fixedly connected to the side wall of the top end of the connecting pipe.

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

[0017] According to the thermal desorption sampling ion source with separation function provided by the present application, the sample separation column is a capillary tube, and the capillary tube is fixedly communicated with the glass lining pipe and the sampling tube at both ends.

[0018] The top end of the sample inlet tube and the two ends of the glass lining tube are detachably connected with sealing connectors, and the two ends of the capillary are fixedly communicated with the two sealing connectors.

[0019] The heating system comprises a heating rod and a temperature measuring rod, and the heating rod and the temperature measuring rod are fixedly connected to the mounting seat.

[0020] The filter assembly comprises a gasket and a fixed nut, the gasket is padded at the top end of the connecting pipe, the fixed nut is threadedly connected at the top end of the connecting pipe, a through hole is formed in the middle position of the fixed nut, and the gasket is arranged between the fixed nut and the connecting pipe.

[0021] The filter material comprises a quartz cotton group, and the quartz cotton group is filled in the glass lining tube.

[0022] The ionization cavity is made of metal, the heat insulation pad is made of ceramic, and the heat insulation pad is fixed to the top end of the ionization cavity through a fixed bolt.

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

[0024] The present application introduces a sample separation column between the sample inlet unit and the sample inlet tube. Since different components in the sample have different distribution coefficients between the stationary phase and the mobile phase, their moving speeds in the sample separation column are also different. The components with smaller distribution coefficients have higher concentrations in the mobile phase and thus move faster. The components with larger distribution coefficients have higher concentrations in the stationary phase and thus move slower, thereby achieving separation. Unlike traditional ionization sources, the present application uses air as the carrier gas, which ensures the sensitivity and detection speed while achieving integration and miniaturization, so as to realize on-site rapid detection.

[0025] The present application increases the sample separation column between the sample inlet unit and the sample inlet tube. The sample molecules are rapidly separated and detected in the sample separation column by the mobile phase, which can greatly reduce the ionization competition of target compounds in the atmospheric pressure ionization source, improve the sensitivity and quantitative stability, and realize more accurate and rapid detection. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed in the embodiments. Obviously, the drawings described below only illustrate some of the embodiments of the present application, and other drawings can be obtained by those of ordinary skill in the art without any creative effort based on these drawings.

[0027] Figure 1 Structure diagram of the pyrolysis sampling ion source with separation function.

[0028] 1, spacer; 2, fixed nut; 3, solvent injection pipe; 4, gas inlet pipe; 5, sampling heating device; 6, glass lining pipe; 7, quartz cotton group; 8, sealing connector; 9, capillary; 10, heating cavity; 11, temperature measuring rod; 12, heating rod; 13, heat insulation pad; 14, sealing ring; 15, ionization unit; 16, detection unit; 17, ionization cavity; 18, ionization area; 19, waste liquid outlet. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present application.

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

[0031] Reference Figure 1 The present application provides a pyrolysis sampling ion source with separation function, comprising:

[0032] An ionization cavity 17 is detachably connected with a heat insulation pad 13 at the top end of the ionization cavity 17;

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

[0034] A sampling system, the heating cavity 10 includes a sampling unit installed at the top end of the heating cavity 10, a sampling pipe is fixedly connected to the mounting seat, the sampling pipe passes through the heating cavity 10, the heat insulation pad 13 and extends into the ionization cavity 17, and the sampling unit and the sampling pipe are communicated through a sample separation column;

[0035] A heating system is installed on the mounting seat;

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

[0037] A detection unit 16 is vertically fixed and connected on the other side wall of the ionization cavity 17, and is correspondingly arranged between the ionization unit 15 and the sample injection tube.

[0038] The bottom of the ionization cavity 17 is provided with a waste liquid port 19, and the ionization unit 15, the detection unit 16 and the sample injection tube form an ionization area 18.

[0039] The application introduces a sample separation column between the sample injection unit and the sample injection tube. Because the distribution coefficients of different components in the sample between the stationary phase and the mobile phase are different, the moving speeds of the components in the sample separation column are also different. The components with smaller distribution coefficients have higher concentration in the mobile phase and thus move faster; the components with larger distribution coefficients have higher concentration in the stationary phase and thus move slower, thereby realizing separation. Different from the traditional ionization source, the application uses air as the carrier gas, realizes the design of integration and miniaturization, guarantees the sensitivity and detection speed, and realizes on-site rapid detection.

[0040] The application increases the sample separation column between the sample injection unit and the sample injection tube, and the flow 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 target compounds of the atmospheric pressure ionization source, improve the sensitivity and quantitative stability, and realize more accurate and rapid detection.

[0041] In a further optimization scheme, the sample injection unit comprises a fixed seat fixedly connected to the top end of the heating cavity 10, a connecting tube is fixedly connected to the fixed seat in the vertical direction, a filter assembly is installed at the top end of the connecting tube, a glass lining tube 6 is fixedly connected to the bottom end of the connecting tube, the glass lining tube 6 is filled with filter material, a sample injection heating device 5 is installed on the outer wall of the connecting tube, the sample injection heating device 5 is fixed to 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] In a further optimization scheme, a sealing ring 14 is arranged between the heat insulation pad 13 and the heating cavity 10.

[0043] In a further optimization scheme, the sample separation column is a capillary tube 9, and the capillary tube 9 is fixedly connected to the glass lining tube 6 and the sample injection tube at both ends, respectively.

[0044] Further optimization scheme, the top of the sample tube and both ends of the glass liner 6 are respectively detachably connected with sealing connectors 8, and both ends of the capillary tube 9 are fixedly communicated with the two sealing connectors 8.

[0045] Further optimization scheme, 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 fixedly connected to the mounting seat.

[0046] Further optimization scheme, the filter assembly comprises a spacer 1 and a fixed nut 2, the spacer 1 is padded at the top of the connecting pipe, the fixed nut 2 is threadedly connected at the top of the connecting pipe, a through hole is formed in the middle of the fixed nut 2, and the spacer 1 is arranged between the fixed nut 2 and the connecting pipe.

[0047] Further optimization scheme, the filter material comprises a quartz cotton group 7, and the quartz cotton group 7 is filled in the glass liner 6.

[0048] Further optimization scheme, the ionization cavity 17 is made of metal, the heat insulation pad 13 is made of ceramic, and the heat insulation pad 13 is fixedly connected to the top of the ionization cavity 17 by a fixed bolt.

[0049] When working, the air with organic matter removed by the activated carbon filter is used as the carrier gas, and the carrier gas is controlled by the flow rate control unit (damping or electronic flow controller EFC or electronic pressure controller EPC, the flow rate is controlled within 0-1000 ml / min). The heating cavity 10 and the injector are heated to the appropriate range by the heating rod 12, the waste liquid pump is connected to 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 air inlet device. Then, the air inlet device, the waste liquid pump and the injection pump are turned on in sequence, and the flow rate of the carrier gas, the flow rate of the solvent and the pumping speed of the waste liquid pump are set. The high voltage is applied to the corona needle by the mass spectrometer, and the mass spectrometer control detection unit 16 is turned on and operated. At this time, the mass spectrum can be observed to generate ionization signals, and the collected mass spectrum is electric noise. At this time, the sample needle can be prepared for sampling to extract a certain volume of sample, and the sample needle is inserted into the connecting pipe through the through hole in the solid nut and enters the connecting pipe through the spacer 1. 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 action of the carrier gas flow of the air inlet device, the sample gas phase molecules enter the capillary 9 through the glass lining pipe 6. In the capillary 9, different components of the separated sample enter the ionization chamber 17 in time sequence due to the chromatographic principle. The corona needle of the ionization unit 15 discharges to generate gas phase ions of the sample to be tested. The gas phase ions are rapidly absorbed in the high vacuum 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 is consistent with the background ionization signal without sampling, the experiment can be ended and the detection unit 16 can be stopped. At this time, the next sampling can be directly carried out. If the next sampling is not needed, the flow rate of the injected solvent and the flow rate of the guiding gas flow are increased to quickly complete the cleaning. This sampling and ionization source mode is not only used for chemical ionization source, but also can be used for other ion sources such as ESI, DBD I, DART, EESI, GD, laser, single photon ionization and other external ion sources.

[0050] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0051] The above-described embodiments are only descriptions of the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A thermal desorption sampling ion source with band separation, characterized in that, The application relates to a GC-MS ionization device. The ionization cavity (17) is detachably connected with a heat insulation pad (13) at the top end; A heating cavity (10) is fixed at the top end of the heat insulation pad (13), and a mounting seat is arranged at the bottom in the heating cavity (10); A sample injection system is arranged on the heating cavity (10) and comprises a sample injection unit arranged at the top end of the heating cavity (10), a sample injection tube is fixedly connected to the mounting seat, the sample injection tube penetrates through the heating cavity (10), the heat insulation pad (13) and extends into the ionization cavity (17), and the sample injection unit and the sample injection tube are communicated through a sample separation column; A heating system is arranged on the mounting seat; An ionization unit (15) is vertically fixed on one side wall of the ionization cavity (17), and the ionization unit (15) is vertically arranged between the sample injection tube; A detection unit (16) is vertically fixedly connected to the other side wall of the ionization cavity (17), and the detection unit (16) is correspondingly arranged between the ionization unit (15); The bottom of the ionization cavity (17) is provided with a waste liquid outlet (19), and an ionization area (18) is formed between the ionization unit (15), the detection unit (16) and the sample injection tube; The sample injection unit comprises a fixing seat fixedly connected to the top end of the heating cavity (10), a connecting tube is vertically fixedly connected to the fixing seat, a filter assembly is arranged at the top end of the connecting tube, a glass lining tube (6) is fixedly connected to the bottom end of the connecting tube, the glass lining tube (6) is filled with filter material, a sample injection heating device (5) is arranged on the outer wall of the connecting tube, the sample injection heating device (5) is fixed to the fixing seat, 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; The sample separation column is a capillary tube (9), and the capillary tube (9) is fixedly communicated with the glass lining tube (6) and the sample injection tube at two ends respectively; The top end of the sample injection tube and the two ends of the glass lining tube (6) are detachably connected with sealing connectors (8), and the two ends of the capillary tube (9) are fixedly communicated with the two sealing connectors (8) respectively.

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

3. The thermal desorption sampling ion source with a 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 fixedly connected to the mounting seat.

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

5. The thermal desorption sampling ion source with a separation function according to claim 2, characterized in that: The filter material comprises a quartz cotton group (7), and the quartz cotton group (7) is filled in the glass lining tube (6).

6. The thermal desorption sampling ion source with a separation function according to claim 1, characterized in that: The ionization cavity (17) is made of metal, and the heat insulation pad (13) is made of ceramic, and the heat insulation pad (13) is fixed on the top end of the ionization cavity (17) through fixing bolts.

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