An ion mobility spectrometer and sniffing device based on pulse sampling

Abstract

An ion migration spectrometer and a sniffing device are provided. The ion migration spectrometer comprises: an ion migration spectrometer, which comprises an ion migration tube and a gas inlet, a gas outlet and a migration gas inlet arranged thereon; a sampling gas path, on which a sampling device is arranged, the sampling device comprises a sampling head and a sampling tube, and is configured to temporarily store the sample gas collected by the sampling head in the sampling tube; an injection gas path, the two ends of which are respectively connected to the gas inlet and the gas outlet of the ion migration tube, the sampling tube is connected in parallel to the injection gas path, and is configured to introduce the carrier gas in the ion migration tube into the sampling tube, and load the sample gas temporarily stored in the sampling tube into the ion migration tube; and a valve assembly, which is configured to only allow gas to flow from the sampling device to the sampling tube in a sampling state, and only allow gas to flow from the ion migration tube through the sampling tube back to the ion migration tube in an injection state. Pulse suction sampling can be achieved by the valve assembly to improve the detection sensitivity of ion migration.

Description

Technical Field

[0001] The present disclosure relates to the field of detection technology, and in particular to an ion mobility spectrometer based on pulse sampling, and a sniffing device comprising the ion mobility spectrometer. Background Art

[0002] Ion mobility spectrometer has many advantages such as small size, low power consumption, strong portability, fast detection speed, high sensitivity and industrialization, and is widely used in military, national defense, industry, environment and clinical diagnosis. The external environmental background entering the ion mobility spectrometer will interfere with the signal. In order to isolate the external environmental background from entering the ion mobility spectrometer, conventional ion mobility spectrometers all use membrane injection. Among them, the membrane injection method is mainly divided into three modes: wipe sampling membrane injection, aspiration sampling membrane injection and direct thermal analysis membrane injection. It is true that the semipermeable membrane can block water, dust and other environmental background outside the semipermeable membrane during injection to improve the adaptability of the ion mobility spectrometer to the environment, but at the same time, it will also block most of the samples outside the semipermeable membrane, thereby affecting the detection sensitivity of the ion mobility spectrometer.

[0003] While the semipermeable membrane blocks the environmental background from entering the ion migration tube and affecting and contaminating the ion migration spectrometer, it also blocks most of the samples being tested outside the semipermeable membrane, reducing the detection sensitivity of ion migration. Summary of the invention

[0004] The purpose of the present disclosure is to provide an ion migration spectrometer and a sniffing device based on pulse sampling to improve the detection sensitivity of ion migration.

[0005] According to an embodiment of one aspect of the present disclosure, there is provided an ion mobility spectrometer based on pulse sampling, comprising:

[0006] An ion transfer tube, wherein the ion transfer tube is provided with a gas inlet for the sample gas and the carrier gas to flow in, a gas outlet for the gas to flow out, and a migration gas inlet for the migration gas to flow in;

[0007] A sampling gas circuit, wherein a sampling device is provided on the sampling gas circuit, wherein the sampling device comprises a sampling head and a sampling tube, wherein the outlet of the sampling head is connected to the inlet of the sampling tube, and the sampling gas circuit is configured to temporarily store the sample gas collected by the sampling head in the sampling tube;

[0008] an inlet gas circuit, the two ends of which are respectively connected to the gas inlet and the gas outlet of the ion transfer tube, the sampling tube is connected in parallel to the inlet gas circuit, and the inlet gas circuit is configured to introduce the carrier gas in the ion transfer tube into the sampling tube, and to load the sample gas temporarily stored in the sampling tube into the ion transfer tube; and

[0009] A valve assembly, wherein the valve assembly is configured to only allow gas to flow from the sampling device to the sampling tube in a sampling state, and only allow gas to flow from the ion transfer tube through the sampling tube back to the ion transfer tube in an injection state. According to an ion migration spectrometer of an embodiment of the present disclosure, the valve assembly includes a first three-way valve, wherein a first port of the first three-way valve is connected to an outlet of the sampling device, a second port is connected to a gas outlet of the ion transfer tube, and a third port is connected to an inlet of the sampling tube.

[0010] According to an embodiment of the present disclosure, the ion migration spectrometer further includes a circulating gas circuit, which includes a migration gas circulating gas circuit and an injection carrier gas circulating gas circuit, wherein the two ends of the migration gas circulating gas circuit are respectively connected to the gas outlet and the migration gas inlet of the ion migration tube, so as to introduce the migration gas into the ion migration tube from the rear end; and the two ends of the injection carrier gas circulating gas circuit are respectively connected to the gas outlet and the gas inlet of the ion migration tube, so as to introduce the carrier gas into the ion migration tube from the rear end.

[0011] According to an ion migration spectrometer of one embodiment of the present disclosure, the ion migration tube adopts an integrated dual-mode all-ceramic migration tube, the number of the migration gas circulation gas paths is two, and the outlet ends of the two migration gas circulation gas paths are connected to the migration gas inlets on the two ion migration tubes of the integrated dual-mode all-ceramic migration tube in a one-to-one correspondence.

[0012] According to an ion migration spectrometer of an embodiment of the present disclosure, a first flow control valve is provided on the migration gas circulation gas path for controlling the gas flow on the migration gas circulation gas path.

[0013] The ion migration spectrometer according to one embodiment of the present disclosure further includes a first pump, which is disposed downstream of the ion migration tube in the gas flow direction and is used to drive the gas flow.

[0014] The ion migration spectrometer according to one embodiment of the present disclosure further includes a first buffer chamber connected in series on the sample inlet gas path and located between the ion migration tube and the first pump.

[0015] The ion migration spectrometer according to one embodiment of the present disclosure further includes a second flow control valve connected in series on the sample inlet gas path and located between the ion migration tube and the first buffer chamber.

[0016] The ion migration spectrometer according to one embodiment of the present disclosure further includes a second buffer chamber connected in series on the sample inlet gas path and located between the first pump and the first three-way valve.

[0017] According to an ion migration spectrometer of one embodiment of the present disclosure, the inlet end of the migration gas circulation gas path and the inlet end of the injection carrier gas circulation gas path are both connected to the exhaust port of the second buffer chamber, and the second port of the first three-way valve is connected to the exhaust port of the second buffer chamber.

[0018] According to an ion migration spectrometer of one embodiment of the present disclosure, the valve assembly also includes a second three-way valve, the inlet end of the injection carrier gas circulation gas path is connected to the injection gas path through the second three-way valve, and the connection is located between the second buffer chamber and the first three-way valve, and the second three-way valve is configured to only allow gas to flow from the second buffer chamber through a part of the injection gas path to the sampling tube in the injection state, and only allow gas to flow from the second buffer chamber through the injection carrier gas circulation gas path to the ion migration tube in the internal circulation state.

[0019] According to an embodiment of the present disclosure, the ion migration spectrometer further includes a first purification filter, which is arranged on the sample inlet gas path and located between the first pump and the second buffer chamber, and is used to filter the gas passing through the sample inlet gas path.

[0020] According to an embodiment of the present disclosure, the ion migration spectrometer further includes a gas replenishing / deflating gas path for replenishing gas into the ion migration tube or deflating the ion migration spectrometer, wherein the first end of the gas replenishing / deflating gas path is connected to the gas outlet of the ion migration tube, and the second end of the gas replenishing / deflating gas path is connected to the external environment.

[0021] According to an ion mobility spectrometer of an embodiment of the present disclosure, a second purification filter is provided on the air supply / degassing gas path.

[0022] According to an ion migration spectrometer of one embodiment of the present disclosure, the valve assembly also includes a three-way valve, the first end of the air replenishment / air release gas circuit is connected to the injection gas circuit through the three-way valve, and the connection is located between the first pump and the first purification filter, and the three-way valve is configured to only allow gas to flow from the first pump to the first purification filter in the injection state; only allow gas to flow from the first pump to the second purification filter in the air release state; and only allow gas to flow from the second purification filter to the first pump in the air replenishment state.

[0023] According to an ion mobility spectrometer of one embodiment of the present disclosure, a water trap filter is further provided on the air supply / degassing gas path, and the water trap filter is located between the second purification filter and the external environment.

[0024] According to an ion mobility spectrometer of an embodiment of the present disclosure, a second pump is further provided on the sampling gas path for driving the gas flow.

[0025] According to an ion migration spectrometer of an embodiment of the present disclosure, it also includes an air intake cleaning gas circuit, wherein the two ends of the air intake cleaning gas circuit are respectively connected to the outlet of the second pump and the external environment, and the second pump is arranged downstream of the sampling gas circuit in the gas flow direction; the valve assembly also includes a third three-way valve arranged on the air intake cleaning gas circuit and between the second pump and the sampling tube, and the third three-way valve is configured to only allow gas to flow from the sampling tube to the second pump in the air intake cleaning state, and only allow gas to flow from the sampling tube to the ion migration tube in the injection state; a third purification filter is arranged on the air intake cleaning gas circuit, and the air intake cleaning gas circuit is configured to allow clean air to flow through the sampling gas circuit in the air intake cleaning state and be discharged after being filtered by the third purification filter.

[0026] According to an ion migration spectrometer of one embodiment of the present disclosure, it also includes an air blowing cleaning air path, the two ends of which are respectively connected to the inlet of the sampling pump and the external environment, and a fourth purification filter is arranged on the air blowing cleaning air path. The air blowing cleaning air path is configured such that in the air blowing cleaning state, the gas filtered by the fourth purification filter flows to the sampling air path to clean the sampling air path.

[0027] According to an ion migration spectrometer of one embodiment of the present disclosure, the valve assembly also includes a fourth three-way valve located between the second pump and the third three-way valve on the sampling gas path, and the fourth three-way valve is configured to only allow gas to flow from the sampling tube to the second pump in an air suction cleaning state; and only allow gas to flow from the second pump to the sampling tube in a air blowing cleaning state.

[0028] According to an ion mobility spectrometer of an embodiment of the present disclosure, the sampling device is made of a metal tube.

[0029] According to an ion mobility spectrometer of an embodiment of the present disclosure, a heater is provided on the sampling device to ensure that the internal temperature of the sampling device is not lower than a preset temperature.

[0030] According to an ion mobility spectrometer of an embodiment of the present disclosure, a microporous filter device is provided at the inlet of the sampling device for filtering impurities in the sample gas.

[0031] According to an embodiment of another aspect of the present disclosure, a sniffing device is provided, which includes the ion mobility spectrometer as described above.

[0032] According to the pulse sampling-based ion mobility spectrometer and sniffing device described in the above various embodiments of the present disclosure, the ion mobility spectrometer of the sniffing device realizes trace pulse sampling of the sample under test through a valve assembly. This trace pulse sampling and direct injection method can improve the detection sensitivity of the instrument on the one hand, and on the other hand, the sampling and injection volume is low under the premise of ensuring the same detection limit, and even harsh external environments are unlikely to affect the performance of the instrument. In addition, the ion mobility spectrometer provided by the present disclosure also has the function of suction cleaning or blowing cleaning, which can assist in equipment cleaning, thereby improving the working efficiency of the instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the structure of an ion mobility spectrometer based on pulse sampling according to an embodiment of the present disclosure.

[0034] Figure 2 for Figure 1 Schematic diagram of the structure of the pulse sampling based ion mobility spectrometer in the internal circulation state.

[0035] Figure 3 for Figure 1 Schematic diagram of the structure of the pulse sampling based ion mobility spectrometer in the sampling state.

[0036] Figure 4 for Figure 1 Schematic diagram of the structure of the pulse sampling based ion mobility spectrometer in the injection state.

[0037] Figure 5 for Figure 1 Schematic diagram of the structure of the pulse sampling based ion mobility spectrometer in the purge cleaning state. DETAILED DESCRIPTION

[0038] Although the present disclosure is susceptible of various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the accompanying drawings and detailed description are not intended to limit the present disclosure to the specific form disclosed, but on the contrary, are intended to cover all modifications, equivalents and alternative forms falling within the spirit and scope of the present disclosure as defined by the appended claims. The drawings are for illustration purposes and are not drawn to scale.

[0039] The terms "first", "second", etc. are used in this specification not for the purpose of ranking or indicating importance or primary and secondary relationships, but for distinguishing different components.

[0040] According to the overall inventive concept of the present disclosure, an ion migration spectrometer based on pulse sampling is provided, which includes an ion migration tube, a sampling gas path, an injection gas path and a valve assembly, wherein the ion migration tube is provided with a gas inlet for sample gas and carrier gas to flow in, a gas outlet for gas to flow out and a migration gas inlet for migration gas to flow in. The sampling gas path is provided with a sampling device on the sampling gas path, the sampling device includes a sampling head and a sampling tube, the outlet of the sampling head is connected to the inlet of the sampling tube, and the sampling gas path is configured to temporarily store the sample gas collected by the sampling head in the sampling tube. The injection gas path, the two ends of the injection gas path are respectively connected to the gas inlet and the gas outlet of the ion migration tube, the sampling tube is connected in parallel to the injection gas path, and the injection gas path is configured to introduce the carrier gas in the ion migration tube into the sampling tube, and load the sample gas temporarily stored in the sampling tube into the ion migration tube. The valve assembly is configured to only allow gas to flow from the sampling device to the sampling tube in a sampling state, and only allow gas to flow from the ion transfer tube through the sampling tube back to the ion transfer tube in an injection state.

[0041] According to the present disclosure, one end of the sampling tube is connected to the sampling device and the sampling gas path respectively through the valve assembly, so that the valve assembly can be controlled so that in the sampling state, the gas sample collected by the sampling device flows into the sampling tube, and in the sampling state, the gas in the ion migration tube enters the sampling tube through the valve assembly, and the gas sample temporarily stored in the sampling tube is loaded into the ion migration tube. By quickly switching the control valve assembly such as a controller, pulse sampling can be achieved during the rapid connection and disconnection of the sampling gas path, and the pulse injection time can be as low as milliseconds, and the minimum sampling volume of a single pulse can be as low as 10 microliters (such as if the sampling gas flow is 1L / min). This pulse sampling direct injection method can not only improve the sensitivity of trace sniffing, but also minimize the impact of harsh external detection environment on the accuracy of ion migration detection.

[0042] Figure 1 It is a schematic diagram of the structure of an ion mobility spectrometer based on pulse sampling according to an embodiment of the present disclosure.

[0043] In this embodiment, the valve assembly includes a first three-way valve 105A, such as a two-position three-way solenoid valve, wherein a first port of the first three-way valve 105A is connected to the outlet of the sampling device 111, a second port is connected to the gas outlet of the ion transfer tube, and a third port is connected to the inlet of the sampling tube 110. By using a three-way valve, the accuracy of the rapid connection and disconnection time of the sampling gas path can be further improved to achieve pulse sampling.

[0044] It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the valve assembly may also include a first valve (e.g., a first solenoid valve) and a second valve (e.g., a second solenoid valve), wherein the inlet of the first valve is connected to the outlet of the sampling device 111, and the outlet is connected to the inlet of the sampling tube 110, and the inlet of the second valve is connected to the gas outlet of the ion migration tube, and the outlet is connected to the inlet of the sampling tube 110. By precisely controlling the rapid switching of the first valve and the second valve through a controller, rapid connection and disconnection of the sampling gas path can be achieved, thereby realizing pulse sampling.

[0045] like Figures 1 to 5 As shown, the ion transfer tube is provided with a gas inlet, a gas outlet and a migration gas inlet, the gas inlet is used for the carrier gas and the gas sample to enter the ion transfer tube, the gas outlet is used for the gas to flow out of the ion transfer tube, and the migration gas inlet allows the migration gas to enter the ion transfer tube. The ion transfer tube is divided into an ionization reaction zone and a gas migration zone by an ion gate, and a detector for detecting ions is provided at the end of the gas migration zone opposite to the ionization reaction zone.

[0046] like Figure 2 As shown, the ion migration spectrometer also includes a circulating gas circuit, which includes a migration gas circulating gas circuit and an injection carrier gas circulating gas circuit. The two ends of the migration gas circulating gas circuit are respectively connected to the gas outlet and the migration gas inlet of the ion migration tube, and are used to introduce the migration gas from the rear end to the gas migration area of ​​the ion migration tube; the two ends of the injection carrier gas circulating gas circuit are respectively connected to the gas outlet and the gas inlet of the ion migration tube, and are used to introduce the carrier gas from the rear end to the ionization reaction area of ​​the ion migration tube.

[0047] Specifically, in this embodiment, the ion transfer tube is an integrated dual-mode all-ceramic transfer tube, which includes a first ion transfer tube 101A and a second ion transfer tube 101B. Accordingly, there are two transfer gas circulation paths, and the outlet ends of the two transfer gas circulation paths are connected to the transfer gas inlets of the two ion transfer tubes in a one-to-one correspondence.

[0048] It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the ion transfer tube may be any suitable ion transfer tube, or may include only a single ion transfer tube.

[0049] like Figures 1 to 5 As shown, in one embodiment, a first flow control valve 106A is provided on the migration gas circulation gas path for controlling the gas flow on the migration gas circulation gas path, so that the user can choose to perform detection only in the negative mode, only in the positive mode, or simultaneously in the negative and positive modes according to the balance of the electrophilic or nucleophilic properties of the detection sample or the cutting off of the non-corresponding detection mode.

[0050] In this embodiment, if Figures 1 to 5As shown, the ion migration spectrometer also includes a first pump 103A, which is arranged downstream of the ion migration tube in the gas flow direction, for example, in the injection state or in the internal circulation state to drive the gas flow. In an embodiment, the first pump 103A is a diaphragm pump. In addition, the ion migration tube gas path also includes a first buffer chamber 102A connected in series on the injection gas path and located between the ion migration tube and the first pump 103A, for reducing the impact of the pulse gas flow of the first pump 103A on the gas flow in the ion migration spectrometer. Further, the ion migration spectrometer also includes a second buffer chamber 102B connected in series on the injection gas path and located between the first pump 103A and the first three-way valve 105A, to further reduce the impact of the pulse gas flow of the first pump 103A on the gas flow in the ion migration spectrometer. In one embodiment, a buffer film is provided on at least a portion of at least one face of the first buffer chamber 102A and the second buffer chamber 102B to enhance the buffer effect. In one embodiment, the buffer film adopts a buffer film with good elasticity. The material of the buffer film includes but is not limited to latex.

[0051] In order to improve the instrument's selective detection of samples, a second flow control valve 106B is provided on the sample inlet gas path and between the ion migration tube and the first buffer chamber 102A, so that the user can choose to perform detection only in the negative mode, only in the positive mode, or simultaneously in the negative and positive modes according to the electrophilic or nucleophilic properties of the detected sample to balance or cut off the non-corresponding detection mode.

[0052] like Figure 2 As shown, the inlet end of the migration gas circulation path and the inlet end of the injection carrier gas circulation path are both connected to the exhaust port of the second buffer chamber 102B, and the second port of the first three-way valve 105A is connected to the exhaust port of the second buffer chamber 102B. In this way, the gas coming out of the gas outlet of the ion migration tube, entering the sampling tube 110 through the injection gas path, and circulating back to the ion migration tube through the migration gas circulation path and the injection carrier gas circulation path can enter the first purification filter 107A after being buffered by the first buffer chamber 102A, and enter the second buffer chamber 102B for buffering after being filtered by the first purification filter 107A, thereby avoiding the need to set up a purification filter and a buffer chamber again on the circulation gas path, thereby saving manufacturing costs.

[0053] In addition, the valve assembly further includes a second three-way valve 105B, such as a two-position three-way solenoid valve, through which the inlet end of the sample carrier gas circulation path is connected to the sample carrier gas path, and the connection is located between the second buffer chamber 102B and the first three-way valve 105A, and the second three-way valve 105B is configured to only allow gas to flow from the second buffer chamber 102B to the sampling tube 110 through a portion of the sample carrier gas path in the sample injection state, and only allow gas to flow from the second buffer chamber 102B to the ion transfer tube through the sample carrier gas circulation path in the internal circulation state. That is, the sample carrier gas path can be selectively connected to the sample carrier gas circulation path through the second three-way valve 105B.

[0054] In addition, the ion migration spectrometer also includes a first purification filter 107A, which is arranged on the sample gas path and is used to filter the gas passing through the sample gas path. In this embodiment, the first purification filter 107A is located between the first pump 103A and the second buffer chamber 102B. It should be noted that those skilled in the art should understand that in some other embodiments of the present disclosure, the first purification filter 107A can also be arranged at other positions of the sample gas path, such as between the first buffer chamber 102A and the gas outlet of the ion migration tube.

[0055] Furthermore, the ion mobility spectrometer further includes a gas replenishment / gas release gas path for replenishing gas into the ion mobility tube or releasing gas from the ion mobility tube, wherein a first end of the gas replenishment / gas release gas path is connected to a gas outlet of the ion mobility tube, and a second end of the gas replenishment / gas release gas path is connected to an external environment. By setting up the gas replenishment / gas release gas path, the ion mobility tube can automatically replenish gas and release gas according to changes in the environment, micro-sampling, and the temperature of the ion mobility tube itself, thereby realizing rapid sampling.

[0056] In one embodiment, a second purification filter 107B is provided on the air supply / release gas path to purify the gas flowing through the air supply / release gas path to reduce the impact of the outside world on the ion mobility spectrometer and to increase the service life of the gas purifier (molecular sieve, activated carbon, etc.).

[0057] In addition, the valve assembly further includes a fifth three-way valve 104, the first end of the air replenishment / deflating gas path is connected to the sample injection gas path through the fifth three-way valve 104, and the connection is located between the first pump 103A and the first purification filter 107A, and the fifth three-way valve 104 is configured to only allow gas to flow from the first pump 103A to the first purification filter 107A in the injection state; only allow gas to flow from the first pump 103A to the external environment in the deflated state; and only allow gas to flow from the second purification filter 107B to the first pump 103A in the air replenishment state. Through the fifth three-way valve 104, the sample injection gas path, the air replenishment gas path and the deflated gas path can be selectively connected.

[0058] According to this embodiment, a water trap filter 109 is further provided on the air supply / deflation path. The water trap filter 109 is located between the second purification filter 107B and the external environment to further reduce the influence of the external environment on the ion mobility spectrometer.

[0059] like Figure 1 and Figure 5 As shown, a second pump is also provided on the sampling gas path for driving the gas to flow in the sampling gas path.

[0060] The ion migration spectrometer also includes an air intake cleaning gas circuit, the two ends of which are respectively connected to the outlet of the second pump 103B and the external environment, and the second pump 103B is arranged downstream of the sampling gas circuit in the gas flow direction; the valve assembly also includes a third three-way valve 105C, such as a two-position three-way solenoid valve, which is arranged on the air intake cleaning gas circuit and between the second pump 103B and the sampling tube 110. The third three-way valve 105C is configured to only allow gas to flow from the sampling tube 110 to the second pump 103B in the air intake cleaning state, and only allow gas to flow from the sampling tube 110 to the ion migration tube in the injection state; a third purification filter 107C and an air resistor 108A are sequentially arranged along the gas flow direction of the air intake cleaning gas circuit, and the air intake cleaning gas circuit is configured to flow clean air through the sampling gas circuit in the air intake cleaning state and be discharged after being filtered by the third purification filter, so as to achieve cleaning of the sampling gas circuit. In the suction cleaning state, the first three-way valve 105A and the third three-way valve 105C are simultaneously connected to the 0 position, the second pump 103B is continuously opened, and the clean air reaches the sampling tube 110 through the first three-way valve 105A from the sampling device 111 and is discharged through the third three-way valve 105C, the second pump 103B, the third purification filter 107C and the air resistance 108A to achieve cleaning of the pipeline and valve components. In the injection state, the first three-way valve 105A, the second three-way valve 105B, and the third three-way valve 105C are connected to the 1 position. Under the action of the first pump 103A, the ion migration injection carrier gas enters the sampling tube 110 through the second buffer chamber 102B, the second three-way valve 105B and the first three-way valve 105A, and the gas sample temporarily stored in the sampling tube 110 is loaded into the ionization reaction area in the ion migration tube through the third three-way valve 105C.

[0061] In addition, the ion migration spectrometer also includes a purge cleaning gas path, the two ends of which are respectively connected to the inlet of the second pump 103B and the external environment, and the gas block 108B and the fourth purification filter 107D are sequentially arranged along the gas flow direction of the purge cleaning gas path, and the purge cleaning gas path is configured such that the gas filtered by the fourth purification filter flows to the sampling gas path in the purge cleaning state to clean the sampling gas path. The ambient gas passes through the gas block 108B and is purified and filtered by the fourth purification filter 107D, and then is discharged after passing through the second pump 103B, the third three-way valve 105C, the sampling tube 110, the first three-way valve 105A and the sampling device 111, and the pipeline and valve assembly passed through are cleaned.

[0062] In one embodiment, when the ion mobility spectrometer can have both an air suction cleaning gas path and an air blowing cleaning gas path, the valve assembly further includes a fourth three-way valve 105D located between the second pump 103B and the third three-way valve 105C on the sampling gas path, such as a two-position three-way solenoid valve, and the fourth three-way valve 105D is configured to only allow gas to flow from the sampling tube 110 to the second pump 103B in the air suction cleaning state; and only allow gas to flow from the second pump 103B to the sampling tube 110 in the air blowing cleaning state. Specifically, the first port of the fourth three-way valve 105D is connected to a port of the third three-way valve 105C, the second port of the fourth three-way valve 105D is connected to the inlet of the second pump 103B, and the third port of the fourth three-way valve 105D is connected to the outlet of the second pump 103B. When in the air suction cleaning state, the fourth three-way valve 105D is connected to the 0 position, and the first port of the fourth three-way valve 105D is connected to the second port, so that gas enters the second pump 103B under the action of the second pump 103B. The gas is discharged through the third purification filter 107C and the air resistor 108A. When air blowing and cleaning are required, the fourth three-way valve 105D is connected to position 1. At this time, the first port of the fourth three-way valve 105D is connected to the third port, so that the gas entering the second pump 103B through the air resistor 108B and the fourth purification filter 107D is blown through the fourth three-way valve 105D, the third three-way valve 105C and enters the sampling pipe 110 and the sampling device 111 before being discharged, thereby cleaning the pipes and valve components passed through.

[0063] In one embodiment, the sampling device 111 uses a metal tube, such as a stainless steel tube, whose outer diameter does not exceed 5 mm. A heater is provided on the sampling device to ensure that the internal temperature of the sampling device is not lower than a preset temperature, such as 50°C, to facilitate pulse sample storage and injection. A microporous filter device, such as a microporous filter, is provided at the inlet of the sampling device to filter impurities such as dust or particles in the sample gas to prevent dust or particles from blocking the sampling gas path during the sampling process.

[0064] Figure 2 for Figure 1The schematic diagram of the structure of the pulse sampling-based ion migration spectrometer in the internal circulation state, wherein the arrow indicates the direction of gas flow. The second three-way valve 105B is connected to the 0 position. Under the action of the first pump 103A, the internal gas flow of the ion migration tubes 101A and 101B passes through the gas outlet to the first buffer chamber 102A, the first pump 103A, the three-way valve 104, and is filtered through the first purification filter 107A to the second buffer chamber 102B, and then enters the migration gas circulation gas path and the injection carrier gas circulation gas path respectively through the first flow control valve 106A and the second three-way valve 105B, and then returns to the ion migration tube.

[0065] Figure 3 for Figure 1 The schematic diagram of the structure of the pulse sampling-based ion mobility spectrometer in the sampling state, wherein the arrow indicates the direction of the gas flow. The sampling device 111 is placed close to the sample to be tested, and the first three-way valve 105A, the third three-way valve 105C, and the fourth three-way valve 105D are all connected to the 0 position. Under the suction action of the second pump 103B, the gas sample passes through the sampling device 111 and the first three-way valve 105A to reach the sampling tube 110. During pulse sampling, the ion mobility tube is in a state of circulating in the gas flow.

[0066] Figure 4 for Figure 1 The schematic diagram of the structure of the pulse sampling-based ion migration spectrometer in the injection state, wherein the arrow indicates the direction of the gas flow. The ion migration tube is switched from the gas flow internal circulation state to the injection state, that is, the second three-way valve 105B, the first three-way valve 105A and the third three-way valve 105C are simultaneously switched from the original 0 position to the 1 position, and under the action of the first pump 103A, the ion migration injection carrier gas enters the sampling tube 110 through the second buffer chamber 102B, the second three-way valve 105B and the first three-way valve 105A, and the gas sample temporarily stored in the sampling tube 110 is loaded into the ionization reaction area in the ion migration tube through the third three-way valve 105C.

[0067] Figure 5 for Figure 1Schematic diagram of the structure of the pulse sampling-based ion mobility spectrometer in the air blowing cleaning state, where the arrow indicates the direction of the airflow. (1) Air suction cleaning process: The first three-way valve 105A, the third three-way valve 105C and the fourth three-way valve 105D are simultaneously connected to the 0 position, and the second pump 103B is continuously turned on. Clean air is discharged from the sampling device 111 through the first three-way valve 105A to the sampling pipe 110 and through the third three-way valve 105C and the fourth three-way valve 105D, the second pump 103B, the third purification filter 107C and the air block 108A, and the pipelines and valve components passed through are cleaned. (2) Air blowing cleaning: The first three-way valve 105A and the third three-way valve 105C are connected to position 0, and the fourth three-way valve 105D is connected to position 1. The ambient gas passes through the air block 108B and is purified and filtered by the fourth purification filter 107D, and then is discharged through the second pump 103B, the fourth three-way valve 105D, the third three-way valve 105C, the sampling tube 110, the first three-way valve 105A and the sampling device 111, and the pipes and valve components passed through are cleaned. It should be noted that the air blowing cleaning has been purified and filtered, so it can cope with more stringent environmental conditions.

[0068] According to another inventive concept of the present disclosure, a sniffing device is provided, which includes the ion mobility spectrometer based on pulse sampling as described above. The technical effect of the sniffing device corresponds to the technical effect of the ion mobility spectrometer described above, and will not be described here in order to avoid unnecessary repetition.

[0069] In summary, the ion mobility spectrometer and the sniffing device including the above-mentioned ion mobility spectrometer provided by the present disclosure realize trace pulse sampling of the sample to be tested by adopting a valve assembly. This trace pulse sampling and direct injection method can improve the detection sensitivity of the instrument on the one hand, and on the other hand, under the premise of ensuring the same detection limit, the sampling and injection volume is low, and the harsh external environment is unlikely to affect the performance of the instrument. In addition, the sampling gas path designed in this scheme also has the function of suction cleaning or blowing cleaning, which can assist in equipment cleaning and improve the working efficiency of the instrument.

Claims

1. An ion mobility spectrometer based on pulse sampling, characterized in that: include: An ion transfer tube, wherein the ion transfer tube is provided with a gas inlet for the sample gas and the carrier gas to flow in, a gas outlet for the gas to flow out, and a migration gas inlet for the migration gas to flow in; A sampling gas circuit, wherein a sampling device is provided on the sampling gas circuit, wherein the sampling device comprises a sampling head and a sampling tube, wherein the outlet of the sampling head is connected to the inlet of the sampling tube, and the sampling gas circuit is configured to temporarily store the sample gas collected by the sampling head in the sampling tube; An inlet gas circuit, the two ends of which are respectively connected to the gas inlet and the gas outlet of the ion transfer tube, the sampling tube is connected in parallel to the inlet gas circuit, and the inlet gas circuit is configured to introduce the carrier gas in the ion transfer tube into the sampling tube, and to load the sample gas temporarily stored in the sampling tube into the ion transfer tube; and The valve assembly is configured to only allow gas to flow from the sampling device to the sampling tube in a sampling state, and only allow gas to flow from the ion transfer tube through the sampling tube back to the ion transfer tube in an injection state.

2. The ion mobility spectrometer according to claim 1, characterized in that: The valve assembly includes a first three-way valve, a first port of the first three-way valve is connected to the outlet of the sampling device, a second port is connected to the gas outlet of the ion transfer tube, and a third port is connected to the inlet of the sampling tube.

3. The ion mobility spectrometer according to claim 2, characterized in that: It also includes a circulating gas circuit, which includes a migration gas circulating gas circuit and an injection carrier gas circulating gas circuit. The two ends of the migration gas circulating gas circuit are respectively connected to the gas outlet and the migration gas inlet of the ion migration tube, and are used to introduce the migration gas from the rear end into the ion migration tube; the two ends of the injection carrier gas circulating gas circuit are respectively connected to the gas outlet and the gas inlet of the ion migration tube, and are used to introduce the carrier gas from the rear end into the ion migration tube.

4. The ion mobility spectrometer according to claim 3, characterized in that: The ion migration tube adopts an integrated dual-mode all-ceramic migration tube, and the number of the migration gas circulation gas paths is two. The outlet ends of the two migration gas circulation gas paths are connected to the migration gas inlets on the two ion migration tubes of the integrated dual-mode all-ceramic migration tube in a one-to-one correspondence.

5. The ion mobility spectrometer according to claim 3, characterized in that: The migration gas circulation gas path is provided with a first flow control valve for controlling the gas flow on the migration gas circulation gas path.

6. The ion mobility spectrometer according to claim 3, characterized in that: The invention also includes a first pump, which is arranged downstream of the ion transfer tube in the gas flow direction and is used to drive the gas flow.

7. The ion mobility spectrometer according to claim 6, characterized in that: The invention also includes a first buffer chamber which is connected in series on the sample inlet gas path and is located between the ion transfer tube and the first pump.

8. The ion mobility spectrometer according to claim 7, characterized in that: The invention also includes a second flow control valve which is connected in series on the sample inlet gas path and is located between the ion transfer tube and the first buffer chamber.

9. The ion mobility spectrometer according to claim 8, characterized in that: It also includes a second buffer chamber which is connected in series on the sample inlet gas path and is located between the first pump and the first three-way valve.

10. The ion mobility spectrometer according to claim 9, characterized in that: The inlet end of the migration gas circulation gas path and the inlet end of the injection carrier gas circulation gas path are both communicated with the exhaust port of the second buffer chamber, and the second port of the first three-way valve is communicated with the exhaust port of the second buffer chamber.

11. The ion mobility spectrometer according to claim 10, characterized in that: The valve assembly also includes a second three-way valve, the inlet end of the injection carrier gas circulation gas circuit is connected to the injection gas circuit through the second three-way valve, and the connection is located between the second buffer chamber and the first three-way valve. The second three-way valve is configured to only allow gas to flow from the second buffer chamber through a portion of the injection gas circuit to the sampling tube in the injection state, and only allow gas to flow from the second buffer chamber through the injection carrier gas circulation gas circuit to the ion migration tube in the internal circulation state.

12. The ion mobility spectrometer according to claim 9, characterized in that: It also includes a first purification filter, which is arranged on the sampling gas path and located between the first pump and the second buffer chamber, and is used for filtering the gas passing through the sampling gas path.

13. The ion mobility spectrometer according to claim 12, characterized in that: It also includes a gas replenishment / degassing gas path for replenishing gas into the ion migration tube or degassing the ion migration spectrometer. The first end of the gas replenishment / degassing gas path is connected to the gas outlet of the ion migration tube, and the second end of the gas replenishment / degassing gas path is connected to the external environment.

14. The ion mobility spectrometer according to claim 13, characterized in that: A second purification filter is arranged on the air replenishment / deflation air path.

15. The ion mobility spectrometer according to claim 14, characterized in that: The valve assembly also includes a fifth three-way valve, the first end of the air replenishment / deflation air circuit is connected to the injection air circuit through the fifth three-way valve, and the connection is located between the first pump and the first purification filter. The fifth three-way valve is configured to only allow gas to flow from the first pump to the first purification filter in the injection state; only allow gas to flow from the first pump to the second purification filter in the deflation state; and only allow gas to flow from the second purification filter to the first pump in the air replenishment state.

16. The ion mobility spectrometer according to claim 15, characterized in that: A water trap filter is also provided on the air replenishment / deflation air path, and the water trap filter is located between the second purification filter and the external environment.

17. The ion mobility spectrometer according to claim 1, characterized in that: A second pump is also provided on the sampling gas path for driving the gas flow.

18. The ion mobility spectrometer according to claim 17, characterized in that: It also includes an air intake cleaning gas circuit, the two ends of which are respectively connected to the outlet of the second pump and the external environment, and the second pump is arranged downstream of the sampling gas circuit in the gas flow direction; the valve assembly also includes a third three-way valve arranged on the air intake cleaning gas circuit and between the second pump and the sampling tube, and the third three-way valve is configured to only allow gas to flow from the sampling tube to the second pump in the air intake cleaning state, and only allow gas to flow from the sampling tube to the ion migration tube in the injection state; a third purification filter is arranged on the air intake cleaning gas circuit, and the air intake cleaning gas circuit is configured to allow clean air to flow through the sampling gas circuit in the air intake cleaning state and be discharged after being filtered by the third purification filter.

19. The ion mobility spectrometer according to claim 18, characterized in that: It also includes an air blowing cleaning air circuit, the two ends of which are respectively connected to the inlet of the sampling pump and the external environment, and a fourth purification filter is arranged on the air blowing cleaning air circuit. The air blowing cleaning air circuit is constructed so that in the air blowing cleaning state, the gas filtered by the fourth purification filter flows to the sampling air circuit to clean the sampling air circuit.

20. The ion mobility spectrometer according to claim 19, characterized in that: The valve assembly also includes a fourth three-way valve located between the second pump and the third three-way valve on the sampling gas path, and the fourth three-way valve is configured to only allow gas to flow from the sampling tube to the second pump in an air suction cleaning state; and only allow gas to flow from the second pump to the sampling tube in a air blowing cleaning state.

21. The ion mobility spectrometer according to any one of claims 1 to 20, characterized in that: The sampling device is made of a metal tube.

22. The ion mobility spectrometer according to any one of claims 1 to 20, characterized in that: The sampling device is provided with a heater to ensure that the internal temperature of the sampling device is not lower than a preset temperature.

23. The ion mobility spectrometer according to any one of claims 1 to 20, characterized in that: The inlet of the sampling device is provided with a microporous filtering device for filtering impurities in the sample gas.

24. A sniffing device, characterized in that: Comprising an ion mobility spectrometer according to any one of claims 1-23.

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