Method for improving peak height of ion mobility spectrometry by controlling pulsed drift gas

Abstract

The invention provides a method for improving the peak height of an ion mobility spectrometry by controlling pulsed drift gas, which comprises the following steps of: feeding the drift gas into an ion migration tube from a Faraday disc, blowing the drift gas through a migration region and an ion gate, and discharging the drift gas from a front gas outlet of a lamp ionization source of a reaction region; carrier gas is fed into the ion migration tube from one side, close to the reaction region, of the ion gate, is blown through the reaction region and is discharged from a gas outlet in front of a lamp ionization source of the reaction region; within a certain time interval, the drift gas flow speed is controlled to be rapidly switched between the high flow speed and the low flow speed, and pulsed drift gas is generated; a to-be-detected sample is connected in series in a gas path of carrier gas, and the to-be-detected sample is carried by the carrier gas to enter the ion migration tube for ionization and detection, so that the ion peak height is increased. According to the invention, the pulse drift gas change is rapidly controlled, that is, the drift gas is rapidly switched between two flows, so that the peak height of the ion mobility spectrometry is increased.

Description

Technical Field

[0001] The invention relates to the technical field of ion mobility spectrometry, and in particular to a method for controlling pulsed drift gas to increase the peak height of ion mobility spectrometry. Background Art

[0002] Ion Mobility Spectrometry (IMS) is a technique that uses an ionization source to ionize gas-phase molecules and analyze chemical substances by using the difference in migration speeds of different gas-phase ions in the same electric field. It has been widely used in the rapid screening and detection of explosives, drugs and poisons on site.

[0003] In ion mobility spectrometry, drift gas is an important analytical condition. Drift gas ensures the normal operation, signal stability and detection effect of the ion mobility spectrometer. Drift gas helps to effectively distinguish different substances through interaction with product ions, removes neutral impurity molecules, and ensures the cleanliness of the migration zone. In the ion mobility spectrometer, the product ions formed after the sample is ionized will drift toward the signal receiving Faraday disk under the action of the electric field. The presence of drift gas can collide with these ions, thereby affecting the migration path and speed of the ions. The product ions generated by different substances have different mobilities under the same electric field. Therefore, by measuring the time required for ions to pass through the drift zone, the mobility of the ions can be calculated, and the type of the detected object can be identified accordingly. The drift gas flow rate and stability directly affect the migration time of ions in the drift tube. Different drift gas flow rates and their fluctuations will cause changes in ion migration time, thereby affecting the accuracy of the analysis results.

[0004] In the existing ion mobility spectrometry technology, Li Haiyang and others invented an ion mobility spectrometry pulse purge negative pressure thermal desorption sampler and injection method (patent number 202111535952.X), which combines pulse purge, negative pressure and thermal desorption technology for detecting solid, liquid and gaseous samples. The sample to be tested undergoes a phase change process when heated under negative pressure, and the gaseous sample molecules are carried into the ion mobility spectrometer by the pulse purge carrier gas for ionization and detection. The pulse purge inlet end of the invention is connected to the gas used for purge, and cooperates with the turntable sampling mechanism to convert the liquid or solid sample to be tested into a gaseous sample. The pulse purge frequency is set to 50Hz, and the pulse width is 10ms; the negative pressure vacuum port end is connected to the ion mobility spectrometer, and is used for negative pressure vacuum sampling. The pressure in the thermal desorption chamber is 70kPa, and the carrier gas flow rate is 400mL / min. Under the conditions of the carrier gas switch pulse frequency of 50Hz and the pulse width of 10ms, the pressure in the thermal desorption chamber is 70kPa. The stability of the pressure indicates the stability of the carrier gas flow rate, so the carrier gas flow rate is fixed.

[0005] Wang Xin and others invented an ion mobility spectrometer control gas circuit (patent number 201911136713.X), which uses ion mobility spectrometry as the basic detection technology. The flow and airflow direction of the carrier gas and drift gas are changed alternately in three ways during sample injection, standby, and system cleaning of the analyzer. The final stable carrier gas and drift gas flow and flow control method can reduce system pollution and facilitate accurate and highly sensitive quantification of target samples. This invention changes the airflow direction of the carrier gas and drift gas, and meets the operation requirements of the drift gas and carrier gas during the three modes of sample injection, standby, and system cleaning through stable carrier gas and drift gas flow, without involving periodic switching of the drift gas and carrier gas flow.

[0006] Chen Chuang and others invented a photoionization ion transfer tube with adjustable reagent ions (patent number 202210882322.8). The ion transfer tube contains a first ionization zone, a second ionization zone, and a third ionization zone placed adjacent to each other from left to right. Among them, the first ionization zone is the initial electron generation and ultraviolet light transmission optical path control zone, the second ionization zone is the reagent ion generation zone, and the third ionization zone is the sample ionization zone. Rapidly switching the concentration of the doping reagent in the first ionization zone, that is, the rapid switching and high-purity generation of different reagent ions can be achieved in the second ionization zone. By utilizing the difference in reaction selectivity of different reagent ions, high-selective detection of the sample to be tested can be achieved, or the difference in product ions formed by different reagent ions and the sample to be tested can be utilized to provide more one-dimensional information support for the qualitative and quantitative analysis of the sample to be tested. The invention is to quickly switch the concentration of the doping reagent in the first ionization zone, that is, to achieve rapid switching and high-purity generation of different reaction reagent ions in the second ionization zone, the float gas flow rate is fixed, the carrier gas flow rate is fixed, and the flow rate of the float gas or the carrier gas is not changed.

[0007] When the drift gas flow rate is high, the migration time increases, and the peak height of the gas ion to be measured will decrease; when the drift gas flow rate is low, the migration time decreases, and the peak height of the gas ion to be measured will increase.

[0008] In the above common ion mobility spectrometry techniques, the generated ion intensity / ion peak height value is relatively low, resulting in low sensitivity of the analysis method. Therefore, it is necessary to invent new technologies to increase the ion peak height to improve the sensitivity of the analysis method. Summary of the invention

[0009] According to the above technical problem that the peak height of the existing ion mobility spectrometry technology is low, a method for controlling pulsed drift gas to increase the peak height of the ion mobility spectrometry is provided. The present invention mainly controls the pulsed drift gas to increase the peak height of the ion mobility spectrometry.

[0010] The technical means adopted by the present invention are as follows:

[0011] A method for controlling pulsed drift gas to increase the peak height of ion mobility spectrum comprises the following steps:

[0012] The drift gas is sent from the Faraday disk into the ion transfer tube, and the drift gas is blown through the migration zone and the ion gate, and discharged from the outlet in front of the lamp ionization source in the reaction zone;

[0013] The carrier gas is sent into the ion transfer tube from the side of the ion gate close to the reaction zone, the carrier gas blows through the reaction zone, and is discharged from the gas outlet in front of the lamp ionization source in the reaction zone;

[0014] In a certain time interval, the drift gas flow rate is controlled to switch rapidly between high flow rate and low flow rate to generate pulsed drift gas;

[0015] The sample to be tested is connected in series in the gas path of the carrier gas, and the sample to be tested is carried by the carrier gas into the ion transfer tube for ionization and detection;

[0016] The drift gas flows along the axial direction of the migration zone of the ion migration tube. When the drift gas quickly switches between high flow rate and low flow rate, the drift gas changes the collision behavior between the sample ions to be measured and the drift gas molecules in the migration zone, so that the collision between the sample ions to be measured and the drift gas molecules in the migration zone produces axial wave collision, which weakens the radial diffusion of the sample ions to be measured, or causes the radially diffused ions to return to the central axis, so as to improve the ion signal intensity / peak height.

[0017] Furthermore, the sample to be tested is one of a gas sample, a gas sample generated by a liquid sample through a heating device, and a gas sample generated by a solid sample through a heating device.

[0018] Furthermore, the method of controlling pulsed drift gas to increase the peak height of ion mobility spectrum is implemented based on an ion transfer tube, which includes a lamp ionization source, an ion gate, an electrode ring and an insulating ring, a Faraday disk, and a voltage divider plate;

[0019] The lamp ionization source, the electrode ring, the insulating ring, and the ion gate form a reaction zone, and a carrier gas port and a gas outlet are provided in the reaction zone;

[0020] The ion gate, the electrode ring, the insulating ring and the Faraday disk form a migration zone, and a floating gas port is arranged on the side of the Faraday disk.

[0021] Furthermore, the high flow rate of the drift gas is 1 L / min, and the low flow rate of the drift gas is 0.3 L / min.

[0022] Furthermore, the certain time interval is between 1 and 20 seconds.

[0023] Furthermore, when the drift flow velocity is quickly switched between a high flow velocity and a low flow velocity, the response speed from the low flow velocity to the high flow velocity is between 0.6 and 1.1 seconds.

[0024] Furthermore, when the drift flow velocity is quickly switched between a high flow velocity and a low flow velocity, the response speed from the high flow velocity to the low flow velocity is between 0.6 and 1.1 seconds.

[0025] Furthermore, the sample to be tested is acetone, and the acetone liquid is placed in a reagent bottle, and a vent is provided on the bottle cap, through which the volatile acetone gas sample is released; at a constant temperature, the volatilization amount of acetone is constant.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] In common ion mobility spectrometry techniques, the carrier gas flow rate and drift gas flow rate are constant, and the resulting ion intensity / ion peak height values ​​are relatively low, resulting in low sensitivity of the analytical method. Therefore, it is necessary to invent new technologies to increase the ion peak height to enhance the sensitivity of the analytical method. The present invention increases the ion mobility spectrometry peak height by rapidly controlling the pulse drift gas change, that is, the drift gas is rapidly switched between two flow rates.

[0028] The drift gas flows along the axial direction of the migration zone of the ion migration tube. Under normal circumstances, when the drift gas flow rate is constant at a high flow rate, the number of axial collisions between sample ions and drift gas molecules in the migration zone increases, and the radial diffusion of ions is greater. As a result, the migration time of ions increases, and the ion signal intensity / peak height decreases accordingly. On the contrary, when the drift gas flow rate is constant at a low flow rate, the number of axial collisions between sample ions and drift gas molecules in the migration zone decreases, and the radial diffusion of ions decreases. As a result, the migration time of ions decreases, and the ion signal intensity / peak height increases accordingly.

[0029] The present invention controls pulsed drift gas, that is, when the drift gas switches rapidly between high flow rate and low flow rate, the collision behavior between sample ions and drift gas molecules in the migration zone is changed, so that the collision between sample ions and drift gas molecules in the migration zone is an axial wave collision, which weakens the radial diffusion of ions or causes the radially diffused ions to return to the central axis, resulting in an increase in ion signal intensity / peak height. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 The figure is a flow chart of the method of the present invention.

[0032] Figure 2 This is a peak height tracking diagram of the present invention for controlling pulsed drift gas to increase the peak height of the ion mobility spectrum.

[0033] Figure 3 The present invention provides a drift gas velocity diagram for controlling pulse drift gas to increase the peak height of ion mobility spectra. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0037] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0038] The sample to be tested is one of a gas sample, a gas sample generated by a liquid sample through a heating device, and a gas sample generated by a solid sample through a heating device.

[0039] The method of the present invention is implemented based on an ion transfer tube, which comprises a lamp ionization source, an ion gate, an electrode ring and an insulating ring, a Faraday disk, and a voltage divider plate; a reaction zone is formed between the lamp ionization source, the electrode ring and the insulating ring, and the ion gate, and a carrier gas port and an air outlet are arranged in the reaction zone; a migration zone is formed between the ion gate, the electrode ring and the insulating ring, and the Faraday disk, and a floating gas port is arranged on the side of the Faraday disk.

[0040] like Figure 1 As shown, the present invention provides a method for controlling pulsed drift gas to increase the peak height of ion mobility spectrometry, comprising the following steps:

[0041] The drift gas is sent from the Faraday disk into the ion transfer tube, and the drift gas is blown through the migration zone and the ion gate, and discharged from the outlet in front of the lamp ionization source in the reaction zone;

[0042] The carrier gas is sent into the ion transfer tube from the side of the ion gate close to the reaction zone, the carrier gas blows through the reaction zone, and is discharged from the gas outlet in front of the lamp ionization source in the reaction zone;

[0043] Preferably, the sample to be tested is acetone, and the acetone liquid is placed in a reagent bottle. The bottle cap is provided with an air outlet, and the volatile acetone gas sample is released through the air outlet; at a constant temperature, the volatilization amount of acetone is constant.

[0044] The sample to be tested is connected in series in the gas path of the carrier gas, and the sample to be tested is carried by the carrier gas into the ion transfer tube for ionization and detection;

[0045] In a certain time interval, the drift gas flow rate is controlled to switch rapidly between a high flow rate and a low flow rate to generate pulsed drift gas; the high flow rate of the drift gas is 1 L / min, and the low flow rate of the drift gas is 0.3 L / min. The certain time interval is between 1 and 20 seconds.

[0046] When the drift flow rate is quickly switched between high flow rate and low flow rate, the response speed from low flow rate to high flow rate is between 0.6-1.1 seconds. When the drift flow rate is quickly switched between high flow rate and low flow rate, the response speed from high flow rate to low flow rate is between 0.6-1.1 seconds.

[0047] Figure 2The invention provides a peak height tracking diagram for controlling pulsed drift gas to improve the peak height of ion mobility spectrum. The low drift gas flow rate is 0.3 L / min (tracking time 0-50 seconds), the flow rate is 0.5 L / min (tracking time 50-100 seconds), the high flow rate is 1.0 L / min (tracking time 100-200 seconds), after 200 seconds of tracking time, the drift gas flow rate switches between high and low flow rates, and the pulse interval time is 20 seconds (tracking time 200-340 seconds), 10 seconds (tracking time 340-400 seconds), 5 seconds (tracking time 400-450 seconds), 3 seconds (tracking time 450-500 seconds), and 1 second (tracking time 500-650 seconds) from left to right.

[0048] Figure 3 The present invention is a drift flow velocity diagram for controlling pulse drift gas to improve the peak height of ion mobility spectrum. The low flow velocity of the drift flow velocity is 0.3L / min (tracking time 0-50 seconds), the flow velocity is 0.5L / min (tracking time 50-100 seconds), the high flow velocity is 1.0L / min (tracking time 100-200 seconds), after the tracking time of 200 seconds, the drift flow velocity switches between the high and low flow velocities, and the pulse interval time is 20 seconds (tracking time 200-340 seconds), 10 seconds (tracking time 340-400 seconds), 5 seconds (tracking time 400-450 seconds), 3 seconds (tracking time 450-500 seconds), and 1 second (tracking time 500-650 seconds) from left to right.

[0049] Example 1

[0050] A method for controlling pulsed drift gas to increase the peak height of ion mobility spectrometry, wherein the analysis conditions of the ion mobility spectrometry are:

[0051] The temperature of the migration tube is room temperature 110℃, the inner diameter of the migration zone is 16mm and the length is 7cm, the high pressure is 9.9kv, the door opening time is 50us, the carrier gas is 0.1L / min, the drift gas and the carrier gas flow in the same direction, the outlet is at the end of the reaction zone, and the volatile gas of acetone at a temperature of 33℃ is analyzed as a dopant;

[0052] When the drift gas is fixed at 0.3L / min, the migration time of acetone is 3.42ms and the peak height is 1.8V; when the drift gas is fixed at 1.0L / min, the migration time of acetone is 3.5ms and the peak height of acetone is 0.8V; the difference between the migration times of 3.42 and 3.5ms is taken as 1, respectively, and the method of normalizing the peak migration time of the substance under various conditions can be used to achieve qualitative and quantitative comparison and analysis.

[0053] The low flow rate of drift gas was set to 0.3 L / min, the high flow rate of drift gas was set to 1.0 L / min, the drift gas was controlled to switch quickly between low flow rate and high flow rate, and the switching pulse interval time was changed from 5 to 1 second. The minimum acetone peak height, the maximum acetone peak height, the acetone peak height difference, and the ratio of the average peak height in pulse mode to the peak height in no pulse mode are shown in the table below.

[0054] The pulse drift gas is controlled to switch between 0.3L / min and 1.0L / min, and the peak height signal of the ion mobility spectrum is increased by 4.4 to 5.3 times;

[0055] When the drift flow rate is quickly switched between high and low flow rates, the response speed from low flow rate to high flow rate is 0.6 seconds; the response speed from high flow rate to low flow rate is 0.6 seconds;

[0056]

[0057] Example 2

[0058] A method for controlling pulsed drift gas to increase the peak height of ion mobility spectrometry, wherein the analysis conditions of the ion mobility spectrometry are:

[0059] The temperature of the migration tube is room temperature 110℃, the inner diameter of the migration zone is 16mm and the length is 7cm, the high pressure is 9.9kv, the door opening time is 50us, the carrier gas is 0.1L / min, the drift gas and the carrier gas flow in the same direction, the outlet is at the end of the reaction zone, and the volatile gas of acetone at a temperature of 33℃ is analyzed as a dopant;

[0060] When the drift gas is fixed at 0.3L / min, the migration time of acetone is 3.42ms, and the peak height is 1.8V; when the drift gas is fixed at 0.5L / min, the migration time of acetone is 3.46ms, and the peak height of acetone is 1.2V; the difference between the migration times of 3.42 and 3.46ms is taken as 1, respectively, and the method of normalizing the peak migration time of the substance under various conditions can be used to achieve qualitative and quantitative comparison and analysis.

[0061] The low flow rate of drift gas was set to 0.3 L / min, the high flow rate of drift gas was set to 0.5 L / min, the drift gas was controlled to switch quickly between low flow rate and high flow rate, the switching pulse interval time was changed from 20 to 1 second, and the minimum acetone peak height, maximum acetone peak height, acetone peak height difference, and the ratio of the average peak height in pulse mode to the peak height in no pulse mode were obtained. See the table below.

[0062] The pulse drift gas is controlled to switch between 0.3L / min and 0.5L / min, and the peak height signal of the ion mobility spectrum is increased by 1.9 to 2.5 times;

[0063] When the drift flow rate is quickly switched between high and low flow rates, the response speed from low flow rate to high flow rate is 1.1 seconds; the response speed from high flow rate to low flow rate is 1.1 seconds;

[0064]

[0065]

[0066] Example 3

[0067] A method for controlling pulsed drift gas to increase the peak height of ion mobility spectrometry, wherein the analysis conditions of the ion mobility spectrometry are:

[0068] The temperature of the migration tube is room temperature 110℃, the inner diameter of the migration zone is 16mm and the length is 7cm, the high pressure is 9.9kv, the door opening time is 50us, the carrier gas is 0.1L / min, the drift gas and the carrier gas flow in the same direction, the outlet is at the end of the reaction zone, and the volatile gas of acetone at a temperature of 33℃ is analyzed as a dopant;

[0069] When the drift gas is fixed at 0.3L / min, the migration time of acetone is 3.42ms, and the peak height is 1.8V; when the drift gas is fixed at 0.7L / min, the migration time of acetone is 3.49ms, and the peak height of acetone is 0.9V; the difference between the migration times of 3.42 and 3.49ms is taken as 1, respectively, and the method of normalizing the peak migration time of the substance under various conditions can be used to achieve qualitative and quantitative comparison and analysis.

[0070] The low flow rate of drift gas was set to 0.3 L / min, the high flow rate of drift gas was set to 0.7 L / min, the drift gas was controlled to switch quickly between low flow rate and high flow rate, the switching pulse interval time was changed from 20 to 1 second, and the minimum acetone peak height, maximum acetone peak height, acetone peak height difference, and the ratio of the average peak height in pulse mode to the peak height in no pulse mode were obtained. See the table below.

[0071] The pulse drift gas is controlled to switch between 0.3L / min and 0.7L / min, and the peak height signal of the ion mobility spectrum is increased by 3.0 to 3.9 times;

[0072] When the drift flow rate is quickly switched between high and low flow rates, the response speed from low flow rate to high flow rate is 0.9 seconds; the response speed from high flow rate to low flow rate is 0.9 seconds;

[0073]

[0074]

[0075] Example 4

[0076] A method for controlling pulsed drift gas to increase the peak height of ion mobility spectrometry, wherein the analysis conditions of the ion mobility spectrometry are:

[0077] The temperature of the migration tube is room temperature 110℃, the inner diameter of the migration zone is 16mm and the length is 7cm, the high pressure is 9.9kv, the door opening time is 50us, the carrier gas is 0.1L / min, the drift gas and the carrier gas flow in the same direction, the outlet is at the end of the reaction zone, and the volatile gas of acetone at a temperature of 33℃ is analyzed as a dopant;

[0078] The low flow rate of drift gas was set to 0.3 L / min, and the high flow rate of drift gas was set to 0.5 to 1.0 L / min. The drift gas was controlled to switch quickly between low flow rate and high flow rate. The switching pulse interval was fixed at 3 seconds. The minimum acetone peak height, the maximum acetone peak height, the acetone peak height difference, and the ratio of the average peak height in pulse mode to the peak height in no pulse mode are shown in the table below.

[0079] The pulse drift gas is controlled to switch between 0.3L / min and 0.5-1.0L / min, and the peak height signal of the ion mobility spectrum is increased by 1.8 to 4.7 times;

[0080] When the drift flow rate is quickly switched between high and low flow rates, the response speed from low flow rate to high flow rate is 1.0 second; the response speed from high flow rate to low flow rate is 1.0 second;

[0081]

[0082]

[0083] Example 5

[0084] A method for controlling pulsed drift gas to increase the peak height of ion mobility spectrometry, wherein the analysis conditions of the ion mobility spectrometry are:

[0085] The temperature of the migration tube is room temperature 110℃, the inner diameter of the migration zone is 16mm and the length is 7cm, the high pressure is 9.9kv, the door opening time is 50us, the carrier gas is 0.1L / min, the drift gas and the carrier gas flow in the same direction, the outlet is at the end of the reaction zone, and the volatile gas of acetone at a temperature of 33℃ is analyzed as a dopant;

[0086] The low flow rate of drift gas was set to 0.3 L / min, and the high flow rate of drift gas was set to 0.5 to 1.0 L / min. The drift gas was controlled to switch quickly between low flow rate and high flow rate. The switching pulse interval was fixed at 1 second. The minimum acetone peak height, maximum acetone peak height, acetone peak height difference, and the ratio of the average peak height in pulse mode to the peak height in no pulse mode were obtained as shown in the table below.

[0087] The pulse drift gas is controlled to switch between 0.3L / min and 0.5-1.0L / min, and the peak height signal of the ion mobility spectrum is increased by 2.1 to 4.8 times;

[0088] When the drift flow rate is quickly switched between high and low flow rates, the response speed from low flow rate to high flow rate is 1.0 second; the response speed from high flow rate to low flow rate is 1.0 second;

[0089]

[0090]

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling pulsed drift gas to increase the peak height of ion mobility spectra, characterized in that: The steps include: The drift gas is sent from the Faraday disk into the ion transfer tube, and the drift gas is blown through the migration zone and the ion gate, and discharged from the outlet in front of the lamp ionization source in the reaction zone; The carrier gas is sent into the ion transfer tube from the side of the ion gate close to the reaction zone, the carrier gas blows through the reaction zone, and is discharged from the gas outlet in front of the lamp ionization source in the reaction zone; In a certain time interval, the drift gas flow rate is controlled to switch rapidly between high flow rate and low flow rate to generate pulsed drift gas; The sample to be tested is connected in series in the gas path of the carrier gas, and the sample to be tested is carried by the carrier gas into the ion transfer tube for ionization and detection; The drift gas flows along the axial direction of the migration zone of the ion migration tube. When the drift gas quickly switches between high flow rate and low flow rate, the drift gas changes the collision behavior between the sample ions to be measured and the drift gas molecules in the migration zone, so that the collision between the sample ions to be measured and the drift gas molecules in the migration zone produces axial wave collision, which weakens the radial diffusion of the sample ions to be measured, or causes the radially diffused ions to return to the central axis, so as to improve the ion signal intensity / peak height.

2. The method for increasing the peak height of ion mobility spectrometry by controlling pulsed drift gas according to claim 1, characterized in that: The sample to be tested is one of a gas sample, a gas sample generated by a liquid sample through a heating device, and a gas sample generated by a solid sample through a heating device.

3. The method for increasing the peak height of ion mobility spectrometry by controlling pulsed drift gas according to claim 1, characterized in that: The method for controlling pulsed drift gas to increase the peak height of ion mobility spectrum is implemented based on an ion transfer tube, which includes a lamp ionization source, an ion gate, an electrode ring and an insulating ring, a Faraday disk, and a voltage divider plate; The lamp ionization source, the electrode ring, the insulating ring, and the ion gate form a reaction zone, and a carrier gas port and a gas outlet are provided in the reaction zone; The ion gate, the electrode ring, the insulating ring and the Faraday disk form a migration zone, and a floating gas port is arranged on the side of the Faraday disk.

4. The method for increasing the peak height of ion mobility spectrometry by controlling pulsed drift gas according to claim 1, characterized in that: The high flow rate of the drift gas is 1 L / min, and the low flow rate of the drift gas is 0.3 L / min.

5. The method for increasing the peak height of ion mobility spectrometry by controlling pulsed drift gas according to claim 1, characterized in that: The certain time interval is between 1 and 20 seconds.

6. The method for increasing the peak height of ion mobility spectrometry by controlling pulsed drift gas according to claim 1, characterized in that: When the drift gas flow rate is quickly switched between high flow rate and low flow rate, the response speed from low flow rate to high flow rate is between 0.6 and 1.1 seconds.

7. The method for increasing the peak height of ion mobility spectrometry by controlling pulsed drift gas according to claim 1, characterized in that: When the drift gas flow rate is quickly switched between high flow rate and low flow rate, the response speed from high flow rate to low flow rate is between 0.6 and 1.1 seconds.

8. The method for increasing the peak height of ion mobility spectrometry by controlling pulsed drift gas according to claim 1, characterized in that: The sample to be tested is acetone. Acetone liquid is placed in a reagent bottle. A vent is provided on the bottle cap, and a volatile acetone gas sample is released through the vent. Under a constant temperature, the volatilization amount of acetone is constant.

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