Gas sample concentration chip and preparation method thereof

Abstract

The invention discloses a gas sample concentration chip and a preparation method thereof. The gas sample concentration chip comprises a silicon base, a cover plate, a cylindrical micro-column array, a microfluidic dam, a gas flow micro-channel, a filler injection port and a gas flow inlet / outlet, a flow channel is processed at the upper end of the silicon base through an etching process, and the silicon base and the cover plate are bonded and sealed to form a flow channel cavity; the cylindrical micro-column array is arranged in the flow channel; the microfluidic retaining dams are arranged on the two sides of the flow channel respectively; a filling injection port communicated with the runner cavity is formed in the area, corresponding to the cylindrical micro-column array, of the cover plate; an airflow micro-channel is formed in the outer side area of the microfluidic dam, and the airflow inlet / outlet is formed in the cover plate. The device has the advantages of being small in dead volume, short in airflow path, small in thermal capacity, fast in thermal response, uniform in flow field, high in stability, high in temperature monitoring accuracy, good in sealing performance and high in reliability.

Description

Technical Field

[0001] This invention relates to the field of gas sample concentration chip technology, and in particular to a gas sample concentration chip and its preparation method. Background Technology

[0002] In the field of gas analysis and detection, the demand for the detection of trace gas samples is increasing. However, direct detection is often limited by insufficient instrument sensitivity. Therefore, pre-processing and concentrating gas samples is the most effective way to improve the detection sensitivity of instruments.

[0003] In the existing technology, common gas concentration devices often use tubular structures such as concentration tubes or liner tubes. These structures have the following significant drawbacks.

[0004] 1. Large dead volume: The tubular cavity design results in a lot of stagnation space for gas during flow, and some gas cannot participate in effective concentration, which reduces the concentration efficiency. 2. Long airflow path: The gas needs to flow a long distance along the axis of the tubular structure, which not only prolongs the sample transport process and makes it easy for the gas to diffuse longitudinally, but also makes it easy for the sample to be lost due to adsorption on the tube wall. 3. Low thermal conductivity: The tubular structure has a large overall volume and is mostly made of glass or stainless steel, which has low thermal conductivity. The heating and cooling response is slow, making it difficult to achieve rapid thermal desorption and affecting the timeliness of detection. 4. Uneven flow field distribution: Traditional tubular structures do not have dedicated flow field optimization designs at the inlet and outlet. When gas enters, eddies and local velocity differences are easily generated, resulting in poor concentration in some areas. In addition, the airflow has a large impact pressure on the structure, affecting the stability of the device.

[0005] To address the aforementioned issues, there is an urgent need in this field to develop a gas concentration structure that is smaller in size, has a faster thermal response, and a more uniform flow field, in order to meet the requirements for efficient and rapid gas sample concentration. Summary of the Invention

[0006] In view of the above problems, the present invention is proposed to provide a gas sample concentration chip and its preparation method that overcome or at least partially solve the above problems.

[0007] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0008] According to a first aspect of the present invention, a gas sample concentration chip and its preparation method are provided, comprising: a silicon substrate, a cover plate, a cylindrical micropillar array, a microfluidic dam, a gas flow microchannel, a filler injection port, and a gas flow inlet and outlet; the silicon substrate is made of silicon, and a flow channel is formed on the upper end of the silicon substrate by an etching process; the cover plate is disposed above the flow channel, and the silicon substrate and the cover plate are bonded and sealed to form a flow channel cavity; the cylindrical micropillar array is disposed in the flow channel, and a filler layer is disposed on the cylindrical micropillar array; the microfluidic dam is disposed on both sides of the flow channel, and the microfluidic dam is formed by etching pillars; a filler injection port communicating with the flow channel cavity is disposed on the area of ​​the cover plate corresponding to the cylindrical micropillar array; a flared gas flow microchannel is disposed on the outer area of ​​the microfluidic dam, and the gas flow inlet and outlet are disposed on the cover plate corresponding to the gas flow microchannel.

[0009] In some embodiments of the present invention, a plurality of sensor receiving grooves are etched at the four corners of the silicon substrate, and a temperature sensor is disposed in the sensor receiving groove; the cross-sectional shape of the sensor receiving groove is rectangular, the cross-sectional length of the sensor receiving groove is 2~4mm, and the cross-sectional width of the sensor receiving groove is 1~3mm.

[0010] In some embodiments of the present invention, the filling layer is composed, for example, of an adsorbent material and a metal grid.

[0011] In some embodiments of the present invention, the silicon substrate has a rectangular cross-sectional shape, a cross-sectional length of 20-30 mm, and a cross-sectional width of 6-10 mm.

[0012] In some embodiments of the present invention, the cross-sectional dimensions of the cover plate are the same as those of the silicon substrate; the overall thickness of the cover plate and the silicon substrate is 1.5~2.5mm.

[0013] In some embodiments of the present invention, the cross-sectional shape of the flow channel is rectangular, the cross-sectional length of the flow channel is 15~20mm, and the cross-sectional width of the flow channel is 5~8mm.

[0014] In some embodiments of the present invention, the cylindrical micropillar array is an array structure composed of multiple cylindrical micropillars, wherein the cylindrical micropillars are arranged in parallel or staggered arrangements, the center-to-center distance between adjacent rows of cylindrical micropillars is 0.1~1mm, and the center-to-center distance between adjacent cylindrical micropillars in the same row is 0.1~1mm.

[0015] In some embodiments of the present invention, the diameter of the cylindrical micropillar is 0.1~0.3mm, and the height of the cylindrical micropillar is the same as the depth of the airflow microchannel.

[0016] In some embodiments of the present invention, the cover plate is made of glass or silicon.

[0017] According to a second aspect of the present invention, a method for preparing a gas sample concentration chip is provided, comprising the following steps: S1. Pre-treat the silicon substrate, the pre-treatment including cleaning and drying; S2. Photolithography is used to form a photoresist pattern containing flow channels, cylindrical micropillar arrays, microfluidic dams, airflow microchannels and sensor accommodating grooves on the surface of a silicon substrate, and then the corresponding structure is prepared by etching. S3. Remove residual photoresist from the silicon substrate; S4. Select a cover plate with the same size as the silicon substrate, and use laser drilling technology to open airflow inlet and outlet and filler injection port on the cover plate. Clean and dry the cover plate. S5. The cover plate is precisely aligned with the silicon substrate, so that the cover plate and the cylindrical micropillar array are tightly bonded. The two are bonded through anodizing bonding process to form a gas sample concentration chip.

[0018] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The gas sample concentration chip described in this embodiment of the invention has the advantages of small dead volume, short gas flow path, small heat capacity, fast thermal response, uniform flow field, high stability, high temperature monitoring accuracy, good sealing performance, and strong reliability.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram illustrating the principle structure of a gas sample concentration chip provided in an embodiment of the present invention; Figure 2 This is a schematic flowchart illustrating a method for preparing a gas sample concentration chip according to an embodiment of the present invention. Figure 3 A reference schematic diagram showing the equimolar response of each component sulfide; Figure 4This is a reference diagram showing the peak spectra of different devices.

[0022] Explanation of reference numerals in the attached figures: 1. Silicon substrate; 2. Cover plate; 11. Flow channel; 12. Cylindrical micropillar array; 13. Microfluidic dam; 14. Airflow microchannel; 15. Sensor housing slot; 21. Packing inlet; 22. Airflow inlet and outlet. Detailed Implementation

[0023] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings.

[0024] The accompanying drawings illustrate various structural schematics according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0025] The terms "comprising" and "having," and any variations thereof, as used in this application, are intended to cover non-exclusive inclusion. The term "multiple" as used in this application refers to two or more. In the context of this application, similar or identical components may be denoted by the same or similar reference numerals.

[0026] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0027] Figure 1 This is a schematic diagram of the principle structure of a gas sample concentration chip provided in an embodiment of the present invention, as shown below. Figure 1As shown, the gas sample concentration chip includes: a silicon substrate 1, a cover plate 2, a cylindrical micropillar array 12, a microfluidic dam 13, a gas flow microchannel 14, a filler injection port 21, and a gas flow inlet and outlet 22. The silicon substrate 1 is made of silicon, and a flow channel 11 is formed on the upper end of the silicon substrate 1 through an etching process. The cover plate 2 is placed on top of the flow channel 11, and the silicon substrate 1 and the cover plate 2 are bonded and sealed to form a flow channel cavity. The cylindrical micropillar array 12 is disposed in the flow channel 11, and a filler layer (not shown) is placed on the cylindrical micropillar array 12. The microfluidic dam 13 is disposed on both sides of the flow channel 11. The microfluidic dam 13 is formed by etching pillars, which can prevent the filler layer from being washed out by the gas flow and block particulate matter from entering the flow channel cavity, ensuring the filler layer is filled. The filling stability; the cover plate 2 is provided with a filling injection port in the region corresponding to the cylindrical microcolumn array 12, which is connected to the flow channel cavity, to provide an injection position for the filling layer; the outer region of the microfluidic dam 13 is provided with a funnel-shaped airflow microchannel 14, and the cover plate 2 is provided with airflow inlet and outlet 22 respectively corresponding to the airflow microchannel 14. The external sample gas is introduced into the airflow microchannel 14 through one of the airflow inlet and outlet 22, and enters the cylindrical microcolumn array 12 in the flow channel cavity, and is discharged through the other airflow inlet and outlet 22; the airflow inlet and outlet 22 are respectively connected to airflow transmission lines, and the airflow transmission lines use, but are not limited to, capillary tubes (such as passivated metal tubes or hollow quartz capillary columns) to transmit airflow.

[0028] In this embodiment of the invention, a plurality of sensor receiving grooves 15 are etched at the four corners of the silicon substrate 1. A temperature sensor is disposed in the sensor receiving groove 15 to measure and acquire the temperature data in the flow channel cavity in real time. The cross-sectional shape of the sensor receiving groove 15 is rectangular, the cross-sectional length of the sensor receiving groove 15 is 2~4mm, and the cross-sectional width of the sensor receiving groove 15 is 1~3mm.

[0029] In this embodiment of the invention, the cross-section of the airflow microchannel 14 is designed as a funnel shape, serving as either an input channel or an output channel for the gas sample, which can guide the gas to focus and transport, thereby improving the efficiency of sample introduction and effluent.

[0030] The filling layer is composed, for example, of an adsorbent material and a metal grid. The adsorbent material is used to selectively capture target components, and the material can be selected according to application requirements (such as Tenax TA, Carbopack B, etc.). The metal grid is used to prevent the loss of the filling material. In this embodiment of the invention, the adsorbent material of the filling layer can be drawn into the flow channel cavity from the filling injection port by a vacuum pump to form a negative pressure at the gas inlet and outlet 22 connected to the flow channel cavity; or the adsorbent monomer solution can be injected and coated into the flow channel cavity through in-situ synthesis, and then polymerized or reacted under certain conditions, such as ultraviolet polymerization, to form a three-dimensional porous structure.

[0031] In this embodiment of the invention, the silicon substrate 1 has a rectangular cross-sectional shape, a cross-sectional length of 20-30 mm, and a cross-sectional width of 6-10 mm; the cover plate 2 has the same cross-sectional dimensions as the silicon substrate 1; and the overall thickness of the cover plate 2 and the silicon substrate 1 is 1.5-2.5 mm.

[0032] In this embodiment of the invention, the cross-sectional shape of the flow channel 11 is rectangular, the cross-sectional length of the flow channel 11 is 15~20mm, and the cross-sectional width of the flow channel 11 is 5~8mm.

[0033] In this embodiment of the invention, the cylindrical micropillar array 12 is an array structure composed of multiple cylindrical micropillars. The cylindrical micropillars are arranged in parallel or staggered arrangements. The center-to-center distance between adjacent rows of cylindrical micropillars is 0.1~1mm, and the center-to-center distance between adjacent cylindrical micropillars in the same row is 0.1~1mm. In this embodiment of the invention, an aligned arrangement is preferred to further optimize the flow field.

[0034] In this embodiment of the invention, the diameter of the cylindrical micropillar is 0.1~0.3mm, and the height of the cylindrical micropillar is the same as the depth of the airflow microchannel 14; the cross-section of the cylindrical micropillar is circular, and the tail of the cylindrical micropillar faces the cover plate 2 and is flush with the cover plate 2 to avoid local turbulence during airflow.

[0035] In this embodiment of the invention, the microfluidic dam 13 has a streamlined spindle-shaped cross section. The long axis of the microfluidic dam 13 is aligned with the airflow direction, and the short axis is aligned with the width direction of the channel 11. The height of the microfluidic dam 13 is the same as the depth of the channel 11, which can guide the gas to smoothly enter the channel 11, avoid the generation of eddies, and disperse the airflow impact pressure.

[0036] In this embodiment of the invention, the cover plate 2 is made of glass or silicon.

[0037] The gas sample concentration chip described in this embodiment of the invention has the following advantages compared to the prior art: 1. Small dead volume and short airflow path: Compared with the existing tubular structure, the gas sample concentration chip of the present invention adopts a miniaturized design of flow channel cavity, flow channel 11 and cylindrical micro-pillar array 12. The volume of flow channel cavity is only 1 / 10 to 1 / 50 of that of traditional concentration tube, and the dead volume is significantly reduced. At the same time, the flow path of gas in flow channel 11 is consistent along the length of flow channel 11, eliminating the need for long-distance axial flow. The airflow path is shortened by more than 50%, reducing gas sample retention and loss. 2. Small heat capacity and fast thermal response: The silicon substrate 1 and the glass cover plate 2 have high thermal conductivity (the thermal conductivity of silicon is about 150 W / (m·K) and that of glass is about 1 W / (m·K)). The overall size of the chip is small, and the heat capacity is only 1 / 20 to 1 / 100 of that of the traditional tubular structure. The cylindrical micropillar array 12 can further enhance the thermal conductivity inside the chip, realize rapid thermal desorption and concentration, and significantly shorten the detection time. 3. Uniform flow field and high stability: The microfluidic dams 13 at the airflow inlet and outlet 22 adopt a streamlined spindle-shaped structure, which can guide the gas smoothly into the airflow microchannels 14 and avoid the generation of eddies; at the same time, the spindle-shaped structure can disperse the impact pressure of the airflow on the dam, reducing the pressure by 30%-50% and reducing the risk of dam damage; the arrangement of the cylindrical micro-pillar array 12 further optimizes the flow field, improving the uniformity of the overall flow velocity distribution of the gas in the channel 11 by more than 40%, ensuring consistent concentration effect in each area; 4. Precise temperature monitoring: The special design of the sensor accommodating slot 15 can embed a miniature temperature sensor to collect the temperature of the concentration area in real time, solving the problem that traditional structures cannot control the temperature instantaneously, enabling precise control of thermal desorption temperature error and improving concentration repeatability. 5. Excellent sealing and high reliability: The cover plate 2 and the tail end face of the cylindrical micropillar are sealed by a bonding process, which can effectively prevent gas leakage, with a leakage rate of less than 1×10⁻⁶. -9 Pa·m³ / s; and all components are manufactured in an integrated manner using micro-machining technology, resulting in high structural stability and a significantly improved service life in the concentration-desorption cycle.

[0038] Based on the above embodiments, as a supplement to the above... Figure 1 The present invention provides an embodiment of a method for preparing a gas sample concentration chip, which is similar to the implementation of the structure shown. Figure 1 The structural embodiments shown correspond to the examples provided. Figure 2 As shown, the preparation method of the gas sample concentration chip includes the following steps: S1. Pre-treat the silicon substrate 1, the pre-treatment including cleaning and drying; The embodiments of the present invention select <100> The crystal-oriented single-crystal silicon wafer is cut into a substrate blank of 25.1mm×8.5mm×1mm; it is then ultrasonically cleaned sequentially with acetone, isopropanol, and deionized water (each stage cleaning time 10-15min) to thoroughly remove surface oil and impurities; after cleaning, the silicon substrate 1 is placed in an oven at 80-120℃ and dried for 30-60min to remove surface moisture; the dried silicon substrate 1 is then subjected to surface oxidation treatment to form a silicon dioxide oxide layer, which serves as a mask layer for subsequent photolithography processes, improving photolithography accuracy and pattern adhesion.

[0039] S2. A photoresist pattern containing flow channels 11, cylindrical micropillar arrays 12, microfluidic dams 13, airflow microchannels 14 and sensor accommodating grooves 15 is formed on the surface of silicon substrate 1 using photolithography, and the corresponding structure is then prepared by etching. In this embodiment of the invention, photoresist is coated onto the silicon oxide layer surface of the silicon substrate 1, and a uniformly thick photoresist layer is formed by spin coating. A photolithographic mask containing a flow channel 11, a cylindrical micropillar array 12, a gas flow microchannel 14, a microfluidic dam 13, and a sensor groove pattern is used for exposure. After exposure, development is performed to obtain the photoresist pattern. Then, using the photoresist pattern as a mask, an etching process is used to etch the silicon substrate 1, and the etching depth is consistent with the design depth of the gas flow microchannel 14. During the etching process, the etching rate is controlled to ensure the morphological accuracy of the flow channel 11, the gas flow microchannel 14, the cylindrical micropillar array 12, the microfluidic dam 13, and the sensor groove.

[0040] S3. Remove residual photoresist from silicon substrate 1; After etching, the residual photoresist is removed to obtain the silicon substrate 1.

[0041] S4. Select a cover plate 2 with the same size as the silicon substrate 1, and use laser drilling technology to open airflow inlet and outlet 22 and filler injection port 21 on the cover plate 2. Clean and dry the cover plate 2. In this embodiment of the invention, a glass plate is selected as the cover plate 2. A laser drilling process is used to open an airflow inlet / outlet 22 and a filler injection port 21 on the cover plate 2. The size of the cover plate 2 is consistent with that of the silicon substrate 1. It is ensured that the cover plate 2 is tightly attached to the cylindrical micropillar array 12 on the silicon substrate 1 to ensure the subsequent bonding and sealing effect. Then, the cover plate 2 is cleaned and dried according to the silicon substrate 1 cleaning process in step S1.

[0042] S5. Align the cover plate 2 precisely with the silicon substrate 1 so that the cover plate 2 and the cylindrical micropillar array 12 are tightly bonded together. The two are bonded through anodizing bonding process to form a gas sample concentration chip.

[0043] Example 1 The steps of preparing the gas sample concentration chip by the preparation method described in this embodiment of the invention include, for example: Silicon substrate 1 pretreatment: selection <100> Crystalline monocrystalline silicon wafers were cut into 25.1mm×8.5mm×1mm pieces; they were then ultrasonically cleaned sequentially with acetone for 10 min, isopropanol for 10 min, and deionized water for 15 min; after cleaning, they were dried in a 100℃ oven for 40 min; subsequently, surface oxidation was performed to form a 500nm thick silicon oxide layer. Integrated fabrication of microstructures: AZ6130 photoresist was spin-coated onto the surface of the silicon oxide layer to form a photoresist layer with a thickness of 1.5 μm; exposure was performed using a quartz mask containing a complete microstructure pattern, and the photoresist pattern was obtained after development; using the photoresist as a mask, the silicon substrate 1 was etched using the DRIE process with an etching depth of 0.5 mm and an etching rate of 8 μm / min; after etching, residual photoresist was removed by oxygen plasma ashing; Preparation of cover plate 2: Select borosilicate glass and cut it to 25.1mm×8.5mm×1mm. Laser drilling is used to open sample inlet and outlet circular holes with a diameter of 0.25mm. After cleaning according to the cleaning process of silicon base 1, dry at 100℃ for 30min. Bonding and sealing: The cover plate 2 is precisely aligned with the silicon substrate 1, and bonding is achieved using an anodic bonding process; leak detection is performed using a helium mass spectrometer to ensure a leakage rate <1×10⁻⁶. -9 Pa·m³ / s; Packing injection port 21: Tenax TA adsorbent is injected through packing injection port 21 at a rate of 50 mg.

[0044] The structural parameters of the gas sample concentration chip prepared by the preparation method described in this embodiment of the invention are as follows: Silicon substrate 1: Dimensions are 25.1mm × 8.5mm × 1mm, using... <100> Single-crystal silicon wafers with specific crystal orientation; Airflow microchannel 14: rectangular cross-section, 6.4 mm wide, 0.5 mm deep, and 20.5 mm long; Cylindrical micropillar array 12: includes 25 rows of cylindrical micropillars, 10 in each row, arranged in parallel; the bottom diameter of the cylindrical micropillars is 10μm, the height is 0.5μm, the center-to-center distance between micropillars in adjacent rows is 0.55mm, and the center-to-center distance between adjacent micropillars in the same row is 0.64mm; Microfluidic dam 13: The cross-section is streamlined and spindle-shaped, with a major axis length of 0.25mm, a minor axis length of 0.125mm, and a height of 0.5mm. It is set at the junction of the airflow microchannel 14 and the flow channel 11, 0.5mm away from the edge of the airflow microchannel 14. Sensor receiving groove 15: The cross-section is rectangular, with a length of 3mm, a width of 2mm, and a depth of 0.1mm, and it is etched into the four corners of the silicon substrate 1; Filler injection port 21: Located at the center of silicon substrate 1, with a circular cross-section and a diameter of 0.25 mm; Cover plate 2: The dimensions are 25.1mm×8.5mm×1mm. The round hole on cover plate 2 is drilled by laser and the hole diameter is 0.8mm.

[0045] Performance testing: The gas sample concentration chip prepared in this embodiment was installed in a pre-concentrator. A ppb-level sulfide-containing mixed gas (components: hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, ethanethiol, carbon disulfide, thiophene, and dimethyl disulfide) was used as the sample. A sulfide luminescence detector (based on the principle of selective response to sulfides and producing the same response to equimolar amounts of analytes) was used for evaluation. The evaluation criterion was: the closer the equimolar response of sulfides was to 100%, the better the concentration effect, especially for highly reactive components such as ppb-level hydrogen sulfide and ethanethiol.

[0046] Figure 3 For a reference diagram showing the isomolar response of each component sulfide, please refer to... Figure 3 It can be seen that the equimolar response of each component sulfide at different ppb concentrations (0.5ppb, 1ppb, 2ppb, 5ppb, 8ppb, 10ppb) all exceeded 90%. Among them, the response of components such as hydrogen sulfide and ethanethiol, which had poor concentration effects, was significantly improved compared with traditional concentration methods.

[0047] Meanwhile, under the same concentration conditions, a traditional pre-concentrator (sample gas concentration tube) and a chip-type pre-concentrator (gas sample concentration chip of the present invention) were used to concentrate and analyze 5 ppb sulfur-containing compounds, and the peak elution of the two were compared.

[0048] Figure 4 For reference diagrams of peak spectra from different devices, please refer to... Figure 4 It can be seen that, under the same concentration conditions, the gas sample concentration chip of the present invention produces a higher and sharper peak pattern than the traditional concentrator, which is more conducive to integration calculation and significantly improves detection accuracy and repeatability.

[0049] The method for preparing the gas sample concentration chip described in this embodiment can be used to prepare the gas sample concentration chip provided in the above embodiment. The gas sample concentration chip prepared by the method has the corresponding functional components and beneficial effects of the gas sample concentration chip described in the above embodiment. For details, please refer to the gas sample concentration chip described in the above embodiment. This embodiment will not be repeated here.

[0050] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0051] Similarly, it should be understood that, for the purpose of simplification and aiding understanding of one or more aspects of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of the invention above. Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and it should be noted that the above embodiments are illustrative of the invention and not restrictive, and that alternative embodiments can be devised by those skilled in the art without departing from its scope.

Claims

1. A gas sample concentration chip, characterized by, It comprises: The silicon base is made of silicon material, the upper end of the silicon base is processed with flow channel by etching process, the cover plate is covered on the upper side of the flow channel, and the silicon base and the cover plate are bonded and sealed to form a flow channel cavity; The cylindrical micro column array is arranged in the flow channel, and the cylindrical micro column array is covered with a filling layer; The two sides of the flow channel are respectively provided with the micro fluid control dam, and the micro fluid control dam is formed by etching column; The area of the cover plate corresponding to the cylindrical micro column array is provided with a filling injection port communicated with the flow channel cavity; The outer side area of the micro fluid control dam is provided with a horn-shaped structure of the air flow micro channel, and the cover plate corresponding to the air flow micro channel is respectively provided with the air flow inlet and outlet.

2. The gas sample concentration chip of claim 1, wherein: A plurality of sensor accommodating grooves are etched at four corner positions of the silicon base, and a temperature sensor is arranged in the sensor accommodating groove; The cross-sectional shape of the sensor accommodating groove is rectangular, the cross-sectional length of the sensor accommodating groove is 2-4mm, and the cross-sectional width of the sensor accommodating groove is 1-3mm.

3. The gas sample concentration chip of claim 1, wherein: The filling layer is composed of adsorbent material and metal grid network.

4. The gas sample concentration chip of claim 1, wherein: The cross-sectional shape of the silicon base is rectangular, the cross-sectional length of the silicon base is 20-30mm, and the cross-sectional width of the silicon base is 6-10mm.

5. The gas sample concentration chip of claim 4, wherein: The cross-sectional size of the cover plate is the same as that of the silicon base; The overall thickness of the cover plate and the silicon base is 1.5-2.5mm.

6. The gas sample concentration chip of claim 1, wherein: The cross-sectional shape of the flow channel is rectangular, the cross-sectional length of the flow channel is 15-20mm, and the cross-sectional width of the flow channel is 5-8mm.

7. The gas sample concentration chip of claim 1, wherein: The cylindrical micro column array is an array structure composed of a plurality of cylindrical micro columns, the cylindrical micro columns are arranged in parallel or staggered, the center distance of adjacent rows of cylindrical micro columns is 0.1-1mm, and the center distance of adjacent cylindrical micro columns in the same row is 0.1-1mm.

8. The gas sample concentration chip of claim 7, wherein: The diameter of the cylindrical micro column is 0.1-0.3mm, and the height of the cylindrical micro column is the same as the depth of the air flow micro channel.

9. The gas sample concentration chip of claim 1, wherein: The material of the cover plate is glass or silicon.

10. A method for preparing a gas sample concentration chip, applied to the gas sample concentration chip according to any one of claims 1-9, characterized in that, The method comprises the following steps: S1, pretreating the silicon base, the pretreatment comprising cleaning and drying; S2, forming a photoresist pattern with flow channel, cylindrical micro column array, micro fluid control dam, air flow micro channel and sensor accommodating groove pattern on the surface of the silicon base by photoetching process, and then preparing the corresponding structure by etching process; S3, removing the residual photoresist on the silicon base; S4, selecting a cover plate with the same size as the silicon base, opening the air flow inlet and outlet and the filler injection port on the cover plate by laser drilling process, and cleaning and drying the cover plate; S5, accurately aligning the cover plate and the silicon base, tightly fitting the cover plate and the cylindrical micro column array, and realizing the bonding of the two by positive level bonding process to form a gas sample concentration chip.

Images