Migration spectrum detection device and method with multiple injection modes

Abstract

The present invention provides a migration spectrum detection device and method with multiple injection modes, wherein the migration spectrum detection device comprises a multi-way valve, a quantitative loop, an enrichment tube, a chromatographic column and a migration spectrum analysis unit; a first switching module is used to selectively connect the multi-way valve port to the second switching module or the carrier gas, and a second switching module is used to selectively connect the flow control module to the first switching module or the injection tube; the injection tube is connected to the migration spectrum analysis unit having two parallel migration tubes through a valve; the first damping column and the two ends of the pre-column are respectively connected to the multi-way valve port, and when the multi-way valve is switched, the carrier gas flows through the quantitative loop, the first damping column and the third switching module in sequence; the third switching module is used to selectively connect the sample gas discharged from the first damping column to the chromatographic column or directly connect to the migration spectrum analysis unit; the first pump is respectively connected to the outlets of the two migration tubes, and the second pump is arranged downstream of the flow control module. The present invention has the advantages of high sensitivity and the like.

Description

Technical Field

[0001] The invention relates to ion migration spectrum, and in particular to a migration spectrum detection device and method with multiple injection modes. Background Art

[0002] Gas chromatography uses the difference in the distribution coefficients of different substances in the stationary phase and the mobile phase to make different compounds flow out of the chromatographic column at different times, thereby achieving the purpose of separation. It is usually used in conjunction with various detectors to achieve substance analysis.

[0003] Ion mobility spectrometry (IMS) technology uses the difference in ion mobility of different compounds as a separation and analysis method. It has a low detection limit and is suitable for the analysis of trace substances. However, the difference in ion mobility of different compounds is small, and commercial IMS instruments generally have limited resolution due to limitations such as volume, making it difficult to achieve qualitative and quantitative analysis of complex samples.

[0004] In order to detect complex samples, gas chromatography-ion mobility spectrometry (GC-IMS) is currently commonly used. This method has some shortcomings, such as:

[0005] 1. GC-IMS usually has only one injection mode and cannot switch between multiple injection and analysis modes. In addition, the IMS positive mode and negative mode cannot be used at the same time.

[0006] For IMS analysis units, membrane sampling is relatively common. The principle is: the sample molecules are dissolved on the outer surface of the membrane. Due to the difference in concentration gradient distribution on both sides of the membrane, the sample molecules are driven to diffuse to the other side of the membrane. The sample molecules are then desorbed from the surface by airflow purge elution and enter the IMS for detection.

[0007] The selectivity of IMS is improved by utilizing the different permeabilities of different samples through the membrane. For example, in patent CN202010647793.1, a membrane sampling of a multi-chamber device is used, and the sample gas selectively permeates the membrane from the sample gas chamber into the detection gas chamber. By controlling the pressure at the rear end of the membrane, the sampling efficiency and selectivity are improved.

[0008] The membrane injection method also has its shortcomings. Since only a small number of target compounds in the sample can pass through the membrane and be detected by IMS, the detection sensitivity is reduced to a certain extent. When the sample concentration changes, the response time of the signal intensity change is relatively long. At the same time, when the sample concentration is high, the memory effect on the membrane is more serious. The traditional PDMS membrane has a good filtering effect on H2O when the humidity in the sample is high, but it cannot effectively separate the sample of interest from the mixed gas.

[0009] 2. Switching between IMS and GC-IMS injection modes will cause the internal pressure of the IMS to be unstable and the dual-tube IMS to be unequal. If the pressures of the two IMS are different, the flow rates injected into the dual tubes will be different, thus affecting the stability and accuracy of the measurement results. Summary of the invention

[0010] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a migration spectrum detection device with multiple injection modes.

[0011] The objective of the present invention is achieved through the following technical solutions:

[0012] A migration spectrum detection device with multiple injection modes, comprising a multi-way valve, a quantitative loop, an enrichment tube, a chromatographic column and a migration spectrum analysis unit, wherein the outlet of the chromatographic column is connected to the migration spectrum analysis unit; the migration spectrum detection device with multiple injection modes also comprises:

[0013] A first switching module and a second switching module, wherein the first switching module is used to selectively connect the multi-way valve port to the second switching module or the carrier gas, and the second switching module is used to selectively connect the flow control module to the first switching module or the injection tube;

[0014] A valve, wherein the injection tube is connected to the migration spectrum analysis unit through the valve, and the migration spectrum analysis unit includes two migration tubes connected in parallel, and the two migration tubes work in a positive mode and a negative mode;

[0015] A first damping column, wherein both ends of the first damping column and the pre-column are respectively connected to the multi-way valve port, and when the multi-way valve is switched, the carrier gas flows through the quantitative loop, the first damping column and the third switching module in sequence;

[0016] A third switching module, the third switching module is used to make the sample gas discharged from the pre-column or the first damping column selectively connected to the chromatographic column or directly connected to the migration spectrum analysis unit;

[0017] A first pump and a second pump, wherein the first pump is connected to outlets of the two migration tubes respectively, and the second pump is arranged downstream of the flow control module.

[0018] The present invention also aims to provide a migration spectrum detection method with multiple injection modes, and the present invention aims to be achieved through the following technical solutions:

[0019] According to the detection method of the migration spectrum detection device with multiple injection modes of the present invention, the detection method comprises:

[0020] Migration spectrometry negative pressure injection mode, specifically, the sample gas passes through the valve, two migration tubes and the first pump in sequence;

[0021] The migration spectrometry quantitative loop injection mode, the chromatography-migration spectrometry quantitative loop injection mode and the chromatography-migration spectrometry enrichment tube injection mode respectively include a pre-pumping state, a sampling state, an injection state and a backflush state; in the pre-pumping state, the sample passes through the injection tube, the second switching module, the flow control module and the second pump in sequence; in the sampling state, the sample gas passes through the injection tube, the quantitative loop, the enrichment tube, the first switching module, the second switching module, the flow control module and the second pump in sequence by switching with a multi-way valve; in the backflush state, the carrier gas passes through the first switching module, the enrichment tube, the quantitative loop, the injection tube, the second switching module and the second pump in sequence by switching with a multi-way valve.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. It has multiple injection modes;

[0024] A variety of injection methods have been realized, including IMS direct injection, IMS quantitative loop injection, GC-IMS quantitative loop injection, and GC-IMS enrichment tube injection;

[0025] 2. The dual migration tubes use positive and negative modes for simultaneous monitoring, which can detect all factors that can be measured by IMS at the same time without the need for time-consuming switching between positive and negative modes;

[0026] 3. It can realize the diversion control of the double-tube IMS injection flow, and the differential pressure temperature measurement and floating gas control of the internal pressure of IMS ensure that the injection flow diverted to the two IMS is equal, thereby improving the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings:

[0028] Figure 1 It is a schematic diagram of the structure of a migration spectrum detection device with multiple injection modes according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Figure 1 The following description describes the optional embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to explain the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional embodiments, but is only limited by the claims and their equivalents.

[0030] Example 1

[0031] The migration spectrum detection device with multiple injection modes according to the embodiment of the present invention comprises:

[0032] A multi-way valve, a quantitative loop, an enrichment tube, a chromatographic column and a migration spectrum analysis unit, wherein the outlet of the chromatographic column is connected to the migration spectrum analysis unit, and the structures and connection methods of these devices are all prior arts in the art;

[0033] A first switching module and a second switching module, wherein the first switching module is used to selectively connect the multi-way valve port to the second switching module or the carrier gas, and the second switching module is used to selectively connect the flow control module to the first switching module or the injection tube;

[0034] A valve, wherein the injection tube is connected to the migration spectrum analysis unit through the valve, wherein the migration spectrum analysis unit includes two migration tubes connected in parallel, and the two migration tubes work in a positive mode and a negative mode, so that the positive mode and the negative mode work at the same time;

[0035] A first damping column, wherein both ends of the first damping column are respectively connected to the ports of the multi-way valve, and when the multi-way valve is switched, the carrier gas flows through the quantitative ring, the first damping column and the third switching module in sequence;

[0036] A third switching module, the third switching module is used to make the sample gas discharged from the first damping column selectively connected to the chromatographic column or directly connected to the migration spectrum analysis unit;

[0037] A first pump and a second pump, wherein the first pump is connected to outlets of the two migration tubes respectively, and the second pump is arranged downstream of the flow control module.

[0038] In order to ensure the stability of the gas flow and prevent high-boiling-point components in the sample gas from entering the chromatographic column, the migration spectrum detection device with multiple injection modes further includes:

[0039] A second damping column, one end of which is connected to the multi-way valve port, and the other end of which is connected to the carrier gas;

[0040] A pre-column, both ends of which are connected to the multi-way valve ports, and when the multi-way valve is switched, the carrier gas flows through the enrichment tube, the pre-column and the third switching module in sequence.

[0041] In order to improve working reliability, further, the multi-way valve is a fourteen-way valve, the first port is connected to the injection tube, the second port and the fifth port are connected to the two ends of the quantitative loop, the third port and the twelfth port are connected to the carrier gas, the fourth port is connected to the first damping column, the sixth port and the thirteenth port are connected to the two ends of the enrichment tube, the seventh port and the eleventh port are connected to the two ends of the pre-column, the eighth port is connected to the exhaust pipe, the ninth port is connected to the second damping column, the tenth port is connected to the inlet of the third switching module, and the fourteenth port is connected to the first switching module.

[0042] In order to realize the switching between the negative pressure mode switching and the positive pressure injection mode of the migration spectrum, further, the migration spectrum detection device with multiple injection modes also includes:

[0043] A fourth switching module is used to selectively connect the outlets of the two migration tubes to the inlet or the exhaust port of the first pump.

[0044] In order to achieve the selection of zero gas and carrier gas, further, the migration spectrum detection device with multiple injection modes also includes:

[0045] A fifth switching module and a sixth switching module, wherein the fifth switching module is used to selectively use zero gas or carrier gas as tail gas, and the sixth switching module is used to selectively use zero gas or carrier gas as drift gas.

[0046] In order to monitor the pressure in the two migration tubes in real time, the migration spectrum detection device with multiple injection modes further includes:

[0047] A pressure sensor and a differential pressure sensor, wherein the pressure sensor obtains the pressure in one migration tube, and the differential pressure sensor obtains the difference between the pressures in two migration tubes.

[0048] Figure 1 A flow chart of a migration spectrum detection method with multiple injection modes according to an embodiment of the present invention is schematically shown. Figure 1 As shown, the detection method comprises:

[0049] Migration spectrometry negative pressure injection mode, specifically, the sample gas passes through the valve, two migration tubes and the first pump in sequence;

[0050] The migration spectrometry quantitative loop (positive pressure) injection mode, the chromatography-migration spectrometry quantitative loop (positive pressure) injection mode and the chromatography-migration spectrometry enrichment tube (positive pressure) injection mode respectively include a pre-pumping state, a sampling state, an injection state and a backflush state; in the pre-pumping state, the sample passes through the injection tube, the second switching module, the flow control module and the second pump in sequence; in the sampling state, the sample gas passes through the injection tube, the quantitative loop, the enrichment tube, the first switching module, the second switching module, the flow control module and the second pump in sequence by switching with a multi-way valve; in the backflush state, the carrier gas passes through the first switching module, the enrichment tube, the quantitative loop, the injection tube, the second switching module and the second pump in sequence by switching with a multi-way valve;

[0051] In the migration spectrometry quantitative loop injection mode, the injection state is that the carrier gas passes through the quantitative loop, the first damping column, and the third switching module in sequence, and then directly enters the two migration tubes.

[0052] In the chromatographic-migration spectrometry quantitative loop injection mode, the injection state is that the carrier gas passes through the quantitative loop, the first damping column, the third switching module and the chromatographic column in sequence, and then enters the two migration tubes;

[0053] In the chromatography-migration spectrometry enrichment tube injection mode, the injection state is that the carrier gas passes through the enrichment tube, the pre-column, the third switching module and the chromatography column in sequence and then enters the two migration tubes.

[0054] In order to ensure that the pressures in the two migration tubes are consistent, further, a pressure difference sensor is used to obtain the pressure difference in the two migration tubes, and the pressures of the drift gases entering the two migration tubes are adjusted to make the pressures in the two migration tubes equal.

[0055] Example 2

[0056] An application example of the migration spectrum detection device and method with multiple injection modes according to Example 1 of the present invention.

[0057] In this application example, the multi-way valve is a fourteen-way valve, the first port is connected to the injection tube, the second port and the fifth port are connected to the two ends of the quantitative loop, the third port is connected to the first carrier gas, the twelfth port is connected to the second carrier gas, the fourth port is connected to the first damping column and the inlet of the third switching module in sequence, the sixth port and the thirteenth port are connected to the two ends of the enrichment tube, the seventh port and the eleventh port are connected to the two ends of the pre-column, the eighth port is connected to the exhaust pipe, the ninth port is connected to one end of the second damping column, the other end of the second damping column is connected to the second carrier gas, the tenth port is connected to the inlet of the third switching module, and the fourteenth port is connected to the first switching module;

[0058] The first carrier gas and the second carrier gas use nitrogen, which are respectively sent to the multi-way valve after passing through the pressure control module.

[0059] The injection tube is connected to the second switching module, and the flow control module and the second pump are sequentially arranged downstream of the second switching module; one outlet of the third switching module is sequentially connected to the chromatographic column and the migration spectrum analysis unit, and the other outlet is directly connected to the migration spectrum analysis unit; the flow path between the third switching module and the chromatographic column is sequentially connected to the pressure control module, the diversion module and the drain pipe, the outlet of the first pump is connected to the drain pipe, the inlet of the fourth switching module is connected to the outlets of the two migration tubes, one outlet is connected to the first pump, and the other outlet is connected to the drain pipe;

[0060] The two inlets of the fifth switching module and the sixth switching module are connected to the carrier gas and the zero gas respectively, the outlet of the fifth switching module is connected to the pressure control module and the flow path (between the chromatographic column and the migration spectrum analysis unit) in sequence, the outlet of the sixth switching module is connected to two flow paths, each of which is provided with a pressure control module, and the flow paths are connected to the drift gas inlet of the migration tube;

[0061] The first switching module to the sixth switching module all use electromagnetic three-way valves, the valves use electromagnetic valves, the flow control module uses EFC, and the pressure control module uses EPC.

[0062] The migration spectrum detection method with multiple injection modes of the embodiment of the present invention, that is, the working method of the detection device of the embodiment, is as follows: Figure 1 As shown, the detection method comprises:

[0063] Migration spectrometry negative pressure injection mode, specifically, the sample gas passes through the valve, two migration tubes and the first pump in sequence;

[0064] The migration spectrometry quantitative loop (positive pressure) injection mode, the chromatography-migration spectrometry quantitative loop (positive pressure) injection mode and the chromatography-migration spectrometry enrichment tube (positive pressure) injection mode respectively include a pre-pumping state, a sampling state, an injection state and a backflush state; in the pre-pumping state, the sample passes through the injection tube, the second switching module, the flow control module and the second pump in sequence; in the sampling state, the sample gas passes through the injection tube, the quantitative loop, the enrichment tube, the first switching module, the second switching module, the flow control module and the second pump in sequence by switching with a multi-way valve; in the backflush state, the carrier gas passes through the first switching module, the enrichment tube, the quantitative loop, the injection tube, the second switching module and the second pump in sequence by switching with a multi-way valve;

[0065] In the migration spectrometry quantitative loop injection mode, the injection state is that the carrier gas passes through the quantitative loop, the first damping column, and the third switching module in sequence, and then directly enters the two migration tubes.

[0066] In the chromatographic-migration spectrometry quantitative loop injection mode, the injection state is that the carrier gas passes through the quantitative loop, the first damping column, the third switching module and the chromatographic column in sequence, and then enters the two migration tubes;

[0067] In the chromatography-migration spectrometry enrichment tube injection mode, the injection state is that the carrier gas passes through the enrichment tube, the pre-column, the third switching module and the chromatography column in sequence and then enters the two migration tubes;

[0068] In the above three positive pressure injection modes, the first pump is turned off, and the fourth switching module is switched so that the outlet of the migration tube (not passing through the first pump) is connected to the exhaust port;

[0069] In various injection modes, the pressure difference in the two migration tubes is obtained by using a differential pressure sensor, and the pressure of the floating gas entering the two migration tubes is adjusted to make the pressure in the two migration tubes equal.

Claims

1. A migration spectrum detection device with multiple injection modes, comprising a multi-way valve, a quantitative loop, an enrichment tube, a chromatographic column and a migration spectrum analysis unit, wherein the outlet of the chromatographic column is connected to the migration spectrum analysis unit; characterized in that: The migration spectrum detection device with multiple injection modes also includes: A first switching module and a second switching module, wherein the first switching module is used to selectively connect the multi-way valve port to the second switching module or the carrier gas, and the second switching module is used to selectively connect the flow control module to the first switching module or the injection tube; A valve, wherein the injection tube is connected to the migration spectrum analysis unit through the valve, and the migration spectrum analysis unit includes two migration tubes connected in parallel, and the two migration tubes work in a positive mode and a negative mode; A first damping column, wherein both ends of the first damping column and the pre-column are respectively connected to the multi-way valve port, and when the multi-way valve is switched, the carrier gas flows through the quantitative loop, the first damping column and the third switching module in sequence; A third switching module, the third switching module is used to make the sample gas discharged from the first damping column selectively connected to the chromatographic column or directly connected to the migration spectrum analysis unit; A first pump and a second pump, wherein the first pump is connected to outlets of the two migration tubes respectively, and the second pump is arranged downstream of the flow control module; The multi-way valve is a fourteen-way valve, the first port is connected to the injection tube, the second port and the fifth port are connected to the two ends of the quantitative loop, the third port and the twelfth port are connected to the carrier gas, the fourth port is connected to the first damping column, the sixth port and the thirteenth port are connected to the two ends of the enrichment tube, the seventh port and the eleventh port are connected to the two ends of the pre-column, the eighth port is connected to the exhaust pipe, the ninth port is connected to the second damping column, the tenth port is connected to the inlet of the third switching module, and the fourteenth port is connected to the first switching module.

2. The migration spectrum detection device with multiple injection modes according to claim 1, characterized in that: The migration spectrum detection device with multiple injection modes also includes: A second damping column, one end of which is connected to the multi-way valve port, and the other end of which is connected to the carrier gas; A pre-column, both ends of which are connected to the multi-way valve ports, and when the multi-way valve is switched, the carrier gas flows through the enrichment tube, the pre-column and the third switching module in sequence.

3. The migration spectrum detection device with multiple injection modes according to claim 2, characterized in that: The migration spectrum detection device with multiple injection modes also includes: An exhaust pipe, one end of which is connected to the multi-way valve port; The flow dividing module and the pressure control module, the exhaust pipe is connected to the flow path between the flow dividing module, the pressure control module and the third switching module and the chromatographic column in sequence.

4. The migration spectrum detection device with multiple injection modes according to claim 1, characterized in that: The migration spectrum detection device with multiple injection modes also includes: A fourth switching module is used to selectively connect the outlets of the two migration tubes to the inlet or the exhaust port of the first pump.

5. The migration spectrum detection device with multiple injection modes according to claim 1, characterized in that: The migration spectrum detection device with multiple injection modes also includes: A fifth switching module and a sixth switching module, wherein the fifth switching module is used to selectively use zero gas or carrier gas as tail gas, and the sixth switching module is used to selectively use zero gas or carrier gas as drift gas.

6. The migration spectrum detection device with multiple injection modes according to claim 1, characterized in that: The migration spectrum detection device with multiple injection modes also includes: A pressure sensor and a differential pressure sensor, wherein the pressure sensor obtains the pressure in one migration tube, and the differential pressure sensor obtains the difference between the pressures in two migration tubes.

7. The detection method of the migration spectrum detection device with multiple injection modes according to any one of claims 1 to 6, the detection method comprising: Migration spectrometry negative pressure injection mode, specifically, the sample gas passes through the valve, two migration tubes and the first pump in sequence; The migration spectrometry quantitative loop injection mode, the chromatography-migration spectrometry quantitative loop injection mode and the chromatography-migration spectrometry enrichment tube injection mode respectively include a pre-pumping state, a sampling state, an injection state and a backflush state; in the pre-pumping state, the sample passes through the injection tube, the second switching module, the flow control module and the second pump in sequence; in the sampling state, the sample gas passes through the injection tube, the quantitative loop, the enrichment tube, the first switching module, the second switching module, the flow control module and the second pump in sequence by switching with a multi-way valve; in the backflush state, the carrier gas passes through the first switching module, the enrichment tube, the quantitative loop, the injection tube, the second switching module and the second pump in sequence by switching with a multi-way valve.

8. The detection method according to claim 7, characterized in that: In the migration spectrometry quantitative loop injection mode, the injection state is that the carrier gas passes through the quantitative loop, the first damping column, and the third switching module in sequence, and then directly enters the two migration tubes. In the chromatographic-migration spectrometry quantitative loop injection mode, the injection state is that the carrier gas passes through the quantitative loop, the first damping column, the third switching module and the chromatographic column in sequence, and then enters the two migration tubes; In the chromatography-migration spectrometry enrichment tube injection mode, the injection state is that the carrier gas passes through the enrichment tube, the pre-column, the third switching module and the chromatography column in sequence and then enters the two migration tubes.

9. The detection method according to claim 7, characterized in that: The pressure difference in the two migration tubes is obtained by using a pressure difference sensor, and the pressure of the drift gas entering the two migration tubes is adjusted to make the pressure in the two migration tubes equal.

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