High-field asymmetric waveform ion mobility spectrometry device and detection method

Abstract

The invention belongs to the technical field of analytical instruments, and provides a high-field asymmetric waveform ion mobility spectrometry device and a detection method.The device comprises an upper-layer substrate, a middle-layer substrate and a lower-layer substrate; a through groove is formed in the middle-layer substrate, a plurality of analysis channels are defined by the bottom of the upper-layer substrate, the top of the lower-layer substrate and the inner wall of the through groove, the lengths of the analysis channels are different, and the electrode length of the separation electrode in each analysis channel is matched with the length of the analysis channel; the upper-layer substrate is provided with an ionization source light path window, and the ionization source light path window is located right above the intersection of the analysis channels; a gas inlet is formed in the lower-layer substrate, the gas inlet is located under the ionization source light path window, and gas to be detected enters through the gas inlet, reaches the intersection and is shunted to each analysis channel. According to the invention, high-sensitivity detection is carried out on trace substances by using the high-field asymmetric waveform ion mobility spectrometry.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of analytical instruments, and particularly relates to a high-field asymmetric waveform ion mobility spectrometry device and a detection method. Background Art

[0002] High-field asymmetric waveform ion mobility spectroscopy (FAIMS) is a detection technology that utilizes the different non-linear variations of gaseous ion mobilities under a high electric field to achieve substance separation and identification. With the advantages of fast detection and easy miniaturization through integration with micro-electro-mechanical system (MEMS), FAIMS devices have gradually shown great application potential in on-site detection fields such as food safety, environmental analysis, and medical and health.

[0003] However, in the face of current diversified detection scenarios, existing FAIMS devices are difficult to adapt to various detection scenarios. Specifically, the analysis channels of existing FAIMS devices have fixed sizes. When the analysis channels are short, the FAIMS resolution is low, resulting in overlapping of the spectral peaks of various substances, and thus accurate identification of each substance in the mixture cannot be achieved; when the analysis channels are long, although the FAIMS resolution is improved, the sensitivity will decrease, so it is difficult to perform highly sensitive detection of trace substances. Existing FAIMS devices cannot simultaneously meet the detection performances of high resolution and high sensitivity, and a trade-off needs to be made between the two. Summary of the Invention

[0004] To solve the above problems, the present disclosure provides a high-field asymmetric waveform ion mobility spectrometry device and a detection method, aiming to achieve highly sensitive detection of trace substances using FAIMS.

[0005] To achieve the above object, the present disclosure mainly provides the following technical solutions:

[0006] In a first aspect, the present disclosure provides a high-field asymmetric waveform ion mobility spectrometry device, characterized in that the device includes:

[0007] An upper substrate, a middle substrate, and a lower substrate;

[0008] The middle substrate is provided with a through groove, and the bottom of the upper substrate, the top of the lower substrate, and the inner wall of the through groove enclose a plurality of analysis channels, the lengths of each analysis channel are different, and the electrode length of the separation electrode in each analysis channel is adapted to the length of the analysis channel where it is located;

[0009] The upper substrate is provided with an ionization source optical path window, and the ionization source optical path window is directly above the intersection of each analysis channel;

[0010] The lower substrate is provided with an air inlet, and the air inlet is directly below the ionization source optical path window. The gas to be detected enters through the air inlet and reaches the intersection, and is split into each analysis channel.

[0011] Further, the lower substrate is provided with an air outlet at one end of each analysis channel away from the air inlet.

[0012] Further, each air outlet and the air inlet are circular through holes.

[0013] Further, the through groove is cross-shaped, and the number of analysis channels is 4.

[0014] Further, along the gas flow direction in each analysis channel, an upper separation electrode and an upper detection electrode are sequentially arranged at intervals at the bottom of the upper substrate, and a lower separation electrode and a lower detection electrode are oppositely arranged at the top of the lower substrate. The interval distances between each upper separation electrode and the corresponding upper detection electrode are equal, and the lengths of each upper detection electrode are the same.

[0015] Further, the device further includes:

[0016] A separation voltage source, which is electrically connected to each upper separation electrode;

[0017] A compensation voltage source, which is electrically connected to each lower separation electrode;

[0018] A deflection voltage source, which is electrically connected to each upper detection electrode.

[0019] Further, the value range of the length of each upper separation electrode is from 5 mm to 100 mm, and the widths of each upper separation electrode are equal.

[0020] Further, the value range of the width of each upper separation electrode is from 1 mm to 10 mm.

[0021] Further, the ionization source optical path window is a circular through hole.

[0022] In a second aspect, the present disclosure provides a detection method, which is applied to the high-field asymmetric waveform ion mobility spectrometry device in the first aspect. The method includes:

[0023] Introduce the gas to be detected from the air inlet at a preset flow rate, and ionize the molecules of each substance to be detected in the gas to be detected by using an ultraviolet light ion source;

[0024] Obtain the detection spectrograms corresponding to each analysis channel;

[0025] At least one qualitative detection spectrum is determined in each detection spectrum, and the qualitative detection spectrum is used to identify each substance to be detected in the gas to be detected;

[0026] The characteristic peak position information of each substance to be detected is determined by using each qualitative detection spectrum;

[0027] A quantitative detection spectrum is determined in each detection spectrum, and the length of the analysis channel corresponding to the quantitative detection spectrum is less than the length of the analysis channel corresponding to the qualitative detection spectrum;

[0028] The quantitative detection spectrum is subjected to multi-peak fitting by using the characteristic peak position information of each substance to be detected to obtain a target detection spectrum containing the characteristic peaks of each substance to be detected.

[0029] Compared with the prior art, the present disclosure has the following advantages:

[0030] In the present disclosure, a detection cavity is formed by the bottom of the upper substrate, the top of the lower substrate, and the inner wall of the through groove of the middle substrate. The detection cavity includes a plurality of analysis channels with different lengths, that is, analysis channels with different lengths are integrated, and the electrode length of the separation electrode in each analysis channel corresponds to the length of the analysis channel where it is located. In addition, in the present disclosure, an ionization source optical path window and an air inlet are respectively opened directly above and directly below the intersection of each analysis channel, so that the gas to be detected with the same ionization effect enters each analysis channel. After the gas to be detected enters each analysis channel, the separation electrode in the longer analysis channel is used to qualitatively identify the substance to be detected, and the separation electrode in the shorter analysis channel is used to highly sensitively detect trace substances. The embodiments of the present disclosure achieve FAIMS detection with both high resolution and high sensitivity.

[0031] Other features and advantages of the present disclosure will be described in the following specification, and part of them will become obvious from the specification or be understood by implementing the present disclosure. The objectives and other advantages of the present disclosure can be achieved and obtained through the structures pointed out in the specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 FIG. shows a schematic structural diagram of a high-field asymmetric waveform ion mobility spectrometry device according to an embodiment of the present disclosure;

[0034] Figure 2 Shows the cross-sectional views of the first analysis channel and the second analysis channel according to an embodiment of the present disclosure;

[0035] Figure 3 Shows the cross-sectional views of the third analysis channel and the fourth analysis channel according to an embodiment of the present disclosure;

[0036] Figure 4 Shows the schematic flow diagram of a detection method according to an embodiment of the present disclosure;

[0037] Figure 5 Shows the mixture detection spectrogram of four analysis channels according to an embodiment of the present disclosure;

[0038] Figure 6 Shows the pure substance spectrograms of acetone and toluene and the mixture detection spectrogram according to an embodiment of the present disclosure;

[0039] Figure 7a Shows the detection spectrogram of the first analysis channel before multi-peak fitting according to an embodiment of the present disclosure;

[0040] Figure 7b Shows the detection spectrogram of the first analysis channel after multi-peak fitting according to an embodiment of the present disclosure;

[0041] Figure 8a Shows the detection spectrogram of the second analysis channel after multi-peak fitting according to an embodiment of the present disclosure;

[0042] Figure 8b Shows the detection spectrogram of the second analysis channel after multi-peak fitting according to an embodiment of the present disclosure. Detailed implementation manners

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0044] At present, the traditional structure of the FAIMS device adopts a single analysis channel and cannot adjust the length of the analysis channel according to the detection requirements of resolution and sensitivity in the on-site environment, resulting in poor adaptability to the detection scenario. When the analysis channel is short, the FAIMS resolution is low, and it is difficult to effectively separate and identify mixtures. When the analysis channel is long, although the resolution is improved, it is difficult to achieve highly sensitive detection of trace substances. Therefore, the embodiments of the present disclosure provide a FAIMS device that can be applied to a variety of detection scenarios and has high-resolution and high-sensitivity detection performance at the same time. The FAIMS device of the embodiments of the present disclosure can obtain the detection spectra of both the long analysis channel and the short analysis channel by integrating analysis channels of different lengths. The long analysis channel can qualitatively identify the types of substances corresponding to different spectral peaks with its high-resolution detection performance, and perform multi-peak fitting on the detection spectrum of the short analysis channel according to the positions of the spectral peaks corresponding to different substances, ultimately achieving highly sensitive and high-resolution detection of the substance to be detected.

[0045] Specifically, as Figure 1 shown, the FAIMS device of the embodiments of the present disclosure may include: an upper substrate (1), a lower substrate (2), an intermediate substrate (3), an air inlet (4), a first air outlet (5), a second air outlet (6), a third air outlet (7), a fourth air outlet (8), an ionization source optical path window (10), a first upper separation electrode (11), a second upper separation electrode (12), a third upper separation electrode (13), a fourth upper separation electrode (14), a first upper detection electrode (15), a second upper detection electrode (16), a third upper detection electrode (17), a fourth upper detection electrode (18), a first lower separation electrode (21), a second lower separation electrode (22), a third lower separation electrode (23), a fourth lower separation electrode (24), a first lower detection electrode (25), a second lower detection electrode (26), a third lower detection electrode (27), a fourth lower detection electrode (28), a first analysis channel (31), a second analysis channel (32), a third analysis channel (33), and a fourth analysis channel (34).

[0046] Among them, the bottom of the upper substrate (1) is tightly adhered to the top of the intermediate substrate (3) in the vertical direction, and the top of the lower substrate (2) is also tightly adhered to the bottom of the intermediate substrate (3) in the vertical direction, and the upper substrate (1) and the lower substrate (2) have the same shape. The materials of the upper substrate (1), the lower substrate (2), and the intermediate substrate (3) may be a printed circuit board (PCB) or high borosilicate glass, etc. The intermediate substrate (3) of the embodiments of the present disclosure is provided with a through groove, and the bottom of the upper substrate (1), the top of the lower substrate (2), and the inner wall of the through groove together enclose a detection cavity. The detection cavity is divided into multiple analysis channels. As Figure 1As shown, if the through slot is "cross-shaped", it is divided into 4 analysis channels. In the embodiments of the present disclosure, any number of more than 2 analysis channels can be set according to actual needs. For example, if the through slot is "linear", it can be divided into two analysis channels with different lengths, and if the through slot is "star-shaped", it is divided into 8 analysis channels.

[0047] It should be noted that each analysis channel in the embodiments of the present disclosure can generate a detection spectrogram. The lengths of each analysis channel are different, and the electrode length of the separation electrode in each analysis channel is adapted to the length of the analysis channel where it is located, that is, the electrode length of the separation electrode in the longer analysis channel is longer, and the electrode length of the separation electrode in the shorter analysis channel is correspondingly shorter.

[0048] In the embodiments of the present disclosure, an ionization source optical path window (10) can be opened at the center position of the upper substrate (1). Directly below the center position of the upper substrate (1) is the intersection of each analysis channel, that is to say, the ionization source optical path window (10) is located directly above the intersection of each analysis channel. In addition, in the embodiments of the present disclosure, an air inlet (4) is opened at the center position of the lower substrate (2). The air inlet (4) is located directly below the ionization source optical path window (10), and the axis of the air inlet (4) and the ionization source optical path window (10) can coincide. The gas to be detected enters the detection cavity through the air inlet, first reaches this intersection, and is ionized and then split into each analysis channel at this intersection.

[0049] The FAIMS device in the embodiments of the present disclosure has analysis channels of various lengths, and can obtain omnidirectional and multi-dimensional spectrogram information of the on-site detection environment. It can combine the accurate qualitative identification ability of the longer analysis channel and the high-sensitivity detection ability of the shorter analysis channel to improve the detection performance of mixtures in the on-site environment. The embodiments of the present disclosure solve the problem that traditional FAIMS devices are difficult to simultaneously achieve high resolution and high sensitivity, and improve the detection ability of FAIMS in the field of trace substance detection.

[0050] In addition, due to the characteristics of the "cross-shaped" distribution of the analysis channels in the embodiments of the present disclosure, the flow field distribution of each analysis channel is symmetric, and each analysis channel shares an air inlet (4) and an ion source. At the same time, the air inlet (4) and the ionization source optical path window (10) are respectively located directly above and below the intersection of each analysis channel, so that the detection results of each analysis channel have good consistency.

[0051] Embodiments of the present disclosure can provide an air outlet for each analysis channel, that is, the air outlet is located in the corresponding analysis channel, and the opening position can be at the ends of the upper substrate (1) or at the ends of the lower substrate (2). That is to say, the lower substrate (2) provides an air outlet at one end away from the air inlet (4) for each analysis channel. Since the air inlet (4) in the embodiments of the present disclosure is provided on the lower substrate (2), therefore, providing air outlets on the lower substrate (2) in the embodiments of the present disclosure is more conducive to gas discharge.

[0052] The air inlet (4), the first air outlet (5), the second air outlet (6), the third air outlet (7), and the fourth air outlet (8) in the embodiments of the present disclosure are all circular through holes, which can maximize the inflow and outflow of gas. In addition, the ionization source optical path window (10) in the embodiments of the present disclosure is also a circular through hole, enabling more ultraviolet light ion sources (29) to ionize the gas to be detected.

[0053] The first upper separation electrode (11), the second upper separation electrode (12), the third upper separation electrode (13), the fourth upper separation electrode (14), the first upper detection electrode (15), the second upper detection electrode (16), the third upper detection electrode (17), and the fourth upper detection electrode (18) in the embodiments of the present disclosure are completely attached to the bottom of the upper substrate (1). The first lower separation electrode (21), the second lower separation electrode (22), the third lower separation electrode (23), the fourth lower separation electrode (24), the first lower detection electrode (25), the second lower detection electrode (26), the third lower detection electrode (27), and the fourth lower detection electrode (28) are completely attached to the top of the lower substrate (2).

[0054] The first upper separation electrode (11) and the first lower separation electrode (21), the second upper separation electrode (12) and the second lower separation electrode (22), the third upper separation electrode (13) and the third lower separation electrode (23), and the fourth upper separation electrode (14) and the fourth lower separation electrode (24) respectively form 4 pairs of separation electrodes, that is, the length and width of each pair of separation electrodes are equal. The length value range of each separation electrode can vary between 5 mm and 100 mm, and the widths of all separation electrodes are equal, with a value range of 1 mm to 10 mm.

[0055] The first upper detection electrode (15) and the first lower detection electrode (25), the second upper detection electrode (16) and the second lower detection electrode (26), the third upper detection electrode (17) and the third lower detection electrode (27), and the fourth upper detection electrode (18) and the fourth lower detection electrode (28) respectively form 4 pairs of detection electrodes, that is, the length and width of each pair of detection electrodes are equal. The spacing distances between each upper separation electrode and the corresponding upper detection electrode in the embodiments of the present disclosure are all equal, and the lengths of all upper detection electrodes are the same.

[0056] In the embodiment of the present disclosure, the first analysis channel (31) is composed of a first upper separation electrode (11), a first lower separation electrode (21), a first upper detection electrode (15), a first lower detection electrode (25), and the air flow channel therebetween, and the first analysis channel (31) communicates with the first air outlet (5); the second analysis channel (32) is composed of a second upper separation electrode (12), a second lower separation electrode (22), a second upper detection electrode (16), a second lower detection electrode (26), and the air flow channel therebetween, and the second analysis channel (32) communicates with the second air outlet (6); the third analysis channel (33) is composed of a third upper separation electrode (13), a third lower separation electrode (23), a third upper detection electrode (17), a third lower detection electrode (27), and the air flow channel therebetween, and the third analysis channel (33) communicates with the third air outlet (7); the fourth analysis channel (34) is composed of a fourth upper separation electrode (14), a fourth lower separation electrode (24), a fourth upper detection electrode (18), a fourth lower detection electrode (28), and the air flow channel therebetween, and the fourth analysis channel (34) communicates with the fourth air outlet (8). The lengths of the first analysis channel (31), the second analysis channel (32), the third analysis channel (33), and the fourth analysis channel (34) respectively correspond to the lengths of the first upper separation electrode (11), the second upper separation electrode (12), the third upper separation electrode (13), and the fourth upper separation electrode (14).

[0057] The working mode of the FAIMS device in the embodiment of the present disclosure is specifically as follows:

[0058] As Figure 2 and Figure 3As shown in the figure, all the analysis channels of the embodiments of the present disclosure share an air inlet (4). The gas to be detected flows into the four analysis channels respectively from the air inlet (4), and the molecules of the gas to be detected are ionized into charged ions by the ultraviolet photoionization source (29). The separation voltage source (301) is simultaneously connected to the first upper separation electrode (11), the second upper separation electrode (12), the third upper separation electrode (13), and the fourth upper separation electrode (14). The separation voltage source (301) applies an asymmetric square wave voltage with adjustable frequency, duty cycle, and amplitude. The ions generate an effective displacement perpendicular to the gas flow direction under the high electric field. The compensation voltage source (311) is simultaneously connected to the first lower separation electrode (21), the second lower separation electrode (22), the third lower separation electrode (23), and the fourth lower separation electrode (24). The compensation voltage source (311) applies a DC scanning voltage with an amplitude within a certain range, and the movement trajectory of the ions is corrected and reaches the detection electrode through the separation electrode. The deflection voltage source (321) is simultaneously connected to the first upper detection electrode (15), the second upper detection electrode (16), the third upper detection electrode (17), and the fourth upper detection electrode (18). The deflection voltage source (321) applies a DC voltage with a constant amplitude, so that the ions are deflected under the action of the electric field and collide with the detection electrode. The corresponding current signals are collected by the first weak current detection module 221, the second weak current detection module 241, the third weak current detection module 261, and the fourth weak current detection module 281 respectively, and uploaded to the upper computer to generate a FAIMS detection spectrum of the signal intensity corresponding to different compensation voltage amplitudes.

[0059] The FAIMS resolution increases with the increase of the length of the separation electrode, and the FAIMS sensitivity decreases with the decrease of the length of the separation electrode. The lengths of the separation electrodes of the first analysis channel (31) to the fourth analysis channel (34) of the FAIMS device of the embodiments of the present disclosure increase in sequence. Therefore, the analysis channel with a shorter separation electrode can have a higher detection sensitivity, and the analysis channel with a longer separation electrode can have a higher resolution. First, use the longer analysis channel to qualitatively identify the types of substances corresponding to different spectral peaks, and extract the positions of the spectral peaks corresponding to different substances. Accordingly, multi-peak fitting is performed on the FAIMS spectrum obtained from the shorter analysis channel, so as to obtain a FAIMS spectrum with higher signal intensity and better separation effect of ion peaks (spectral peaks of various substances), realizing effective separation and identification of trace substances and high-sensitivity detection.

[0060] Corresponding to the FAIMS device of the embodiments of the present disclosure, the embodiments of the present disclosure also provide a detection method, which is applied to the FAIMS device of the embodiments of the present disclosure, aiming at effective separation and identification of trace substances and high-sensitivity detection. The detection method is as Figure 4 shown, and the specific steps are as follows:

[0061] S101. Set the high-field asymmetric waveform ion mobility spectrometry device according to the preset parameters.

[0062] In this step, each voltage source can be set. The specific steps are from Step 1 to Step 3:

[0063] Step 1: Set the separated voltage source (301) to output an asymmetric square wave voltage with a frequency of 1 MHz, a duty cycle of 30%, and an amplitude of 800 V.

[0064] Step 2: Set the scanning range of the compensation voltage source (311) to -30 V to 30 V, and the scanning time to 5 s.

[0065] Step 3: Set the deflecting voltage source (321) to output a DC voltage with an amplitude of 20 V.

[0066] S102: Introduce the gas to be detected from the inlet at a preset flow rate, and use an ultraviolet light ion source to ionize the molecules of each substance to be detected in the gas to be detected.

[0067] Among them, the gas to be detected includes a carrier gas and each substance to be detected. The ultraviolet light ion source (29) ionizes the gas to be detected through the ionization source optical path window (10).

[0068] In this step, the gas to be detected can be introduced from the inlet (4) at a flow rate of 5 L / min, and an ultraviolet light ion source (29) with an ionization energy of 10.6 eV is used to ionize the gas to be detected, so that the molecules of each substance to be detected in the gas to be detected are ionized.

[0069] S103: Obtain the detection spectrograms corresponding to each analysis channel.

[0070] In this step, after the gas to be detected is shunted to each analysis channel, each analysis channel obtains its own FA IMS detection spectrogram, and each FA IMS detection spectrogram is different.

[0071] S104: Determine at least one qualitative detection spectrogram from each detection spectrogram. The qualitative detection spectrogram is used to identify each substance to be detected in the gas to be detected.

[0072] S105: Use each qualitative detection spectrogram to determine the characteristic peak position information of each substance to be detected.

[0073] Among them, the characteristic peak position information is used to indicate the position of the characteristic peak of the corresponding substance to be detected in the corresponding FA IMS detection spectrogram.

[0074] In a realizable manner, the determination method of the characteristic peak position information of each substance to be detected specifically includes Step 1 and Step 2.

[0075] Step 1: For each substance to be detected, determine the abscissa of the spectral peak corresponding to the substance to be detected in each qualitative detection spectrogram.

[0076] Step 2: Obtain the average value of each abscissa to get the characteristic peak position information of the substance to be measured.

[0077] In the embodiment of the present disclosure, by obtaining the average value of the spectral peak positions provided by multiple longer analysis channels, high-precision qualitative identification of the substance to be measured is achieved.

[0078] S106: Determine the quantitative detection spectrum in each detected spectrum.

[0079] Among them, the length of the analysis channel corresponding to the quantitative detection spectrum is less than the length of the analysis channel corresponding to the qualitative detection spectrum.

[0080] S107: Perform multi-peak fitting on the quantitative detection spectrum by using the characteristic peak position information of each substance to be measured to obtain a target detection spectrum containing the characteristic peaks of each substance to be measured.

[0081] In the embodiment of the present disclosure, by integrating analysis channels of different lengths, detection spectra with complementary resolution and sensitivity can be obtained. The qualitative identification of the substance to be measured is realized by using a longer analysis channel, and the highly sensitive detection of trace substances is realized by using a shorter analysis channel. The embodiment of the present disclosure realizes FAIMS detection with both high resolution and high sensitivity.

[0082] To describe in more detail the FAIMS device and the corresponding detection method provided by the embodiment of the present disclosure, the detection of a mixture of acetone and toluene will be taken as an example for detailed description below.

[0083] The lengths of the first upper separation electrode (11), the second upper separation electrode (12), the third upper separation electrode (13), and the fourth upper separation electrode (14) are set to be 10 mm, 20 mm, 40 mm, and 80 mm respectively. Correspondingly, the lengths of the first lower separation electrode (21), the second lower separation electrode (22), the third lower separation electrode (23), and the fourth lower separation electrode (24) are set to be 10 mm, 20 mm, 40 mm, and 80 mm respectively. The spacing between each pair of separation electrodes is 0.5 mm, the width of the separation electrodes is 5 mm, the diameter of the air inlet (4) is 5 mm, and the diameters of the first air outlet (5), the second air outlet (6), the third air outlet (7), and the fourth air outlet (8) are all 5 mm. The diameter of the ionization source optical path window (10) is 10 mm. A mixture containing acetone and toluene with a concentration of 0.4 ppm each is introduced through the air inlet (4), and the flow rate of the carrier gas (ambient air) is 5 L / min. The molecules of the substance to be measured are ionized by an ultraviolet light ion source (29) with an ionization energy of 10.6 eV. The separation voltage source (301) is set to output an asymmetric square wave voltage with a frequency of 1 MHz, a duty cycle of 30%, and an amplitude of 800 V; the scanning range of the compensation voltage source (311) is set to -30 V to 30 V, and the scanning time is 5 s; the deflection voltage source (321) is set to output a DC voltage with an amplitude of 20 V.

[0084] Figure 5 are the FAIMS detection spectra obtained for four analysis channels. It can be seen from the figure that the first analysis channel (31) and the second analysis channel (32) have relatively high spectral peaks, but the spectral peaks of different substances overlap; the fourth analysis channel (34) achieves effective separation of multiple spectral peaks with relatively high resolution, but the signal intensity is low. Figure 6 are the FAIMS detection spectra of the mixture of acetone and toluene, pure acetone, and pure toluene obtained for the fourth analysis channel (34). By comparing the peak positions of the spectra of the mixture and the pure substances, it can be seen that the characteristic peak positions of pure acetone and pure toluene are 4.09 V and 6.78 V respectively, and they maintain a quite good one-to-one correspondence with the spectral peaks at 4.35 V and 6.89 V respectively in the FAIMS detection spectrum of the mixture of the two, with errors of only 6.4% and 1.6%. It should be noted that Figure 6 for the spectral curves of the mixture and the pure substances respectively, the spectral peaks near zero are background peaks. Therefore, the fourth analysis channel (34) has good qualitative recognition ability and can provide accurate characteristic peak position information of each substance. The FAIMS detection spectra of the first analysis channel (31) and the second analysis channel (32) can be fitted according to this characteristic peak position information, and the fitting results are respectively as Figure 7b and Figure 8b shown, (the qualitative detection spectra are as Figure 5As shown by the curve corresponding to the fourth analysis channel in, the quantitative detection spectrogram is as Figure 7a and Figure 8a shown. The target detection spectrogram is as Figure 7b and Figure 8b shown). It can be seen from this that before fitting, the first analysis channel (31) and the second analysis channel (32) cannot separate the overlapping peaks. After fitting according to the characteristic peak position information provided by the longer analysis channel, the spectrogram peaks corresponding to different substances can be accurately identified, not only realizing the accurate separation and identification of the mixture, but also achieving detection limits of 3.3 ppb and 1.3 ppb for acetone and toluene respectively, with good detection sensitivity.

[0085] Although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A high-field asymmetric waveform ion mobility spectrometer, characterized in that: The device comprises: An upper substrate, an intermediate substrate and a lower substrate; The middle substrate is provided with a through groove, and the bottom of the upper substrate, the top of the lower substrate and the inner wall of the through groove form a plurality of analysis channels, the lengths of the analysis channels are different, and the lengths of the separation electrodes in each analysis channel are adapted to the lengths of the analysis channels in which they are located; The upper substrate is provided with an ionization source light path window, and the ionization source light path window is located directly above the intersection of each analysis channel; The lower substrate is provided with an air inlet, which is located directly below the ionization source optical path window. The gas to be detected enters through the air inlet and reaches the intersection, and is diverted to each analysis channel.

2. The device according to claim 1, characterized in that The lower substrate has an air outlet for each analysis channel at one end away from the air inlet.

3. The device according to claim 2, characterized in that Each air outlet and the air inlet are circular through holes.

4. The device according to claim 1, characterized in that The through groove is cross-shaped, and the number of the analysis channels is 4.

5. The device according to claim 4, characterized in that In each analysis channel, along the airflow direction, an upper separation electrode and an upper detection electrode are sequentially arranged at intervals at the bottom of the upper substrate, and a lower separation electrode and a lower detection electrode are relatively arranged at the top of the lower substrate, the spacing distance between each upper separation electrode and the corresponding upper detection electrode is equal, and the length of each upper detection electrode is the same.

6. The device according to claim 5, characterized in that The device also includes: a separation voltage source, the separation voltage source being electrically connected to each upper separation electrode; A compensation voltage source, the compensation voltage source being electrically connected to each lower separation electrode; A bias voltage source is electrically connected to each upper detection electrode.

7. The device according to claim 5, characterized in that The length of each upper separation electrode ranges from 5 mm to 100 mm, and the width of each upper separation electrode is equal.

8. The device according to claim 7, characterized in that The width of each upper separation electrode ranges from 1 mm to 10 mm.

9. The device according to any one of claims 1 to 8, characterized in that: The ionization source light path window is a circular through hole.

10. A detection method, characterized in that: Applied to the high-field asymmetric waveform ion mobility spectrometer as described in claims 1-9, the method comprises: The gas to be detected is introduced from the gas inlet at a preset flow rate, and the molecules of each substance to be detected in the gas to be detected are ionized by using an ultraviolet ion source; Obtain the detection spectrum corresponding to each analysis channel; Determining at least one qualitative detection spectrum from each detection spectrum, wherein the qualitative detection spectrum is used to identify each substance to be detected in the gas to be detected; Using each qualitative detection spectrum to determine the characteristic peak position information of each substance to be tested; Determining a quantitative detection spectrum from each detection spectrum, wherein the length of the analysis channel corresponding to the quantitative detection spectrum is shorter than the length of the analysis channel corresponding to the qualitative detection spectrum; The quantitative detection spectrum is subjected to multi-peak fitting using the characteristic peak position information of each substance to be detected, so as to obtain a target detection spectrum containing the characteristic peaks of each substance to be detected.

11. The method according to claim 10, characterized in that The characteristic peak position information of each substance to be tested is determined by using each qualitative detection spectrum, and the method comprises: For each substance to be tested, determining the abscissa of the spectrum peak corresponding to the substance to be tested in each qualitative detection spectrum; The average value of each of the horizontal coordinates is calculated to obtain the characteristic peak position information of the substance to be tested.

Images