Aromatic molecule-imprinted material and electrochemical sensor, and preparation method and application thereof

Abstract

The embodiment of the specification provides an aromatic molecule imprinting material and a preparation method thereof, an aromatic molecule high-selectivity electrochemical sensor and a preparation method thereof, and application of the aromatic molecule high-selectivity electrochemical sensor in detection of dangerous solid waste aromatic molecules. Specifically, the aromatic molecule imprinting material is obtained by taking one molecule selected from toluene or ethylbenzene or dimethylbenzene or chlorobenzene as a template molecule and a porogen, taking 4-vinylpyridine as a functional monomer, taking ethylene glycol dimethacrylate as a crosslinking agent, taking azobisisobutyronitrile as an initiator, removing the template molecule after reaction, and further preparing the aromatic molecule high-selectivity electrochemical sensor based on the aromatic molecule imprinting material. The gas sensor method prepared in the embodiment of the specification is simpler, can realize high-selectivity identification of the aromatic molecule at room temperature, has the characteristics of low manufacturing cost, easy integration, simple and efficient detection method, wide detection range, and has a wide application prospect.

Description

Technical Field

[0001] This application relates to the fields of electrochemical materials and sensor technology, and in particular to an aromatic molecule imprinted material and its preparation method, an aromatic molecule highly selective electrochemical sensor and its preparation method, and the application of the aromatic molecule highly selective electrochemical sensor in the detection of aromatic molecules in hazardous solid waste. Background Technology

[0002] Aromatic hydrocarbons and aromatic-like compounds, such as toluene, p-xylene, and nitrobenzene, pose a significant threat to our health and safety. How to quickly and accurately identify these gases in complex gaseous environments has long been a focus of scientific attention. Compared to traditional GC-FID detectors or GC-MS methods, which suffer from drawbacks such as expensive equipment, slow analysis processes, and inconvenience for real-time on-site analysis, resistive sensors have enormous application potential in the field of gas detection due to their simple fabrication process, low cost, and ease of integration.

[0003] Molecularly imprinted polymers (MIPs) are novel, highly selective recognition materials developed by mimicking the antibody-receptor interaction in nature. Specifically, a target molecule is used as a template, and it binds to a functional monomer through covalent or non-covalent interactions. The polymer then forms a polymer of the functional monomer. After removing the template, a molecularly imprinted cavity is left on the imprinted polymer that matches the spatial structure, size, and shape of the target molecule and has effective action sites. This results in a specific recognition ability for the template molecule and offers advantages such as low cost, high availability, high stability, long lifespan, and the potential for large-scale production. Summary of the Invention

[0004] Microparticles (MIPs) have great potential for improving selectivity and are widely used in various fields. Combining highly selective MIPs with resistive sensors to construct aromatic and aromatic-like gas sensors will help improve their selectivity.

[0005] The embodiments of this specification demonstrate a method for preparing a highly selective electrical sensor for aromatic molecules in hazardous solid waste. This method belongs to the research field of aromatic molecule gas sensors for hazardous solid waste and can achieve high-efficiency identification of carcinogenic and teratogenic aromatic gas molecules at room temperature.

[0006] In one or more embodiments of this specification, an aromatic molecularly imprinted material is provided. This material uses a molecule selected from toluene, ethylbenzene, xylene, or chlorobenzene as a template molecule and a porogen, 4-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as a crosslinking agent, and azobisisobutyronitrile as an initiator. The template molecule is removed after the reaction. The xylene is selected from p-xylene, m-xylene, or o-xylene.

[0007] In one or more embodiments of this specification, a method for preparing an aromatic molecularly imprinted material is provided, including a precipitation polymerization method, specifically: the template molecule, the porogen, the functional monomer, the crosslinking agent and the initiator are mixed uniformly by ultrasonication, an inert gas is introduced to remove oxygen, a thermally initiated polymerization reaction is carried out in an inert gas environment, and the aromatic molecularly imprinted material is obtained after elution.

[0008] Optionally, the reaction conditions for the thermally initiated polymerization reaction include: oil bath at 80 to 110°C, rotation speed at 40 to 70 r / min, and reaction time at 12 to 36 h.

[0009] Optionally, the crosslinking agent and the functional monomer are subjected to vacuum distillation to remove the polymerization inhibitor before use.

[0010] Optionally, the initiator is purified by recrystallization from methanol before use.

[0011] In one or more embodiments of this specification, a highly selective electrochemical sensor for aromatic molecules is provided, which is prepared using aromatic molecule imprinted materials as provided in the embodiments of this specification as functional materials and conductive ink as basic materials.

[0012] Optionally, the preparation method of the aromatic molecule highly selective electrochemical sensor includes: mixing and grinding the aromatic molecule imprinting material, conductive ink and organic molecular binder provided in the embodiments of this specification to obtain a uniformly mixed slurry; coating the slurry onto the interdigitated electrode by spin coating or screen printing to prepare the aromatic molecule highly selective electrochemical sensor.

[0013] Optionally, the mass ratio of the aromatic molecular imprint material, the conductive ink, and the organic molecular binder can be 1:(5-60):(10-100).

[0014] Optionally, the organic molecular binder may include ethyl cellulose and terpineol.

[0015] Optionally, the mass ratio of ethyl cellulose to terpineol in the organic molecular binder is from 5:95 to 3:97.

[0016] Optionally, the interdigitated electrodes are fabricated on a flexible PET substrate using a vacuum thermal deposition method with a mask.

[0017] Optionally, the overall size of the interdigitated electrode is (5-10) × (10-20) mm, comprising 5-10 pairs of electrodes, each pair having a width of 0.1-0.15 mm and a spacing of 0.1-0.15 mm between each pair of electrodes. A higher number of electrode pairs results in a more stable gas response value.

[0018] Optionally, the electrode material of the interdigitated electrode can be chromium or gold.

[0019] Optionally, the spin-coated or screen-printed area is the same size as the interdigitated electrode area.

[0020] In one or more embodiments of this specification, a highly selective electrochemical sensor for aromatic molecules is provided for detecting aromatic molecules (C4444445) in hazardous solid waste. n H 2n+2 Applications in ).

[0021] Optionally, the hazardous solid waste aromatic molecules may include aromatic molecules that are liquid at room temperature.

[0022] Optionally, the hazardous solid waste aromatic molecules may include monocyclic or polycyclic aromatic molecules lacking a recognition site, wherein the recognition site includes a hydroxyl, carboxyl, or amino group.

[0023] Optionally, the hazardous solid waste aromatic molecules may include toluene, ethylbenzene, xylene, chlorobenzene, nitrobenzene, or naphthalene.

[0024] The gas sensor prepared in the embodiments of this specification is simpler to prepare than the complex gas detection sensors currently available at high temperatures. It can achieve highly selective recognition of aromatic molecules at room temperature and has the characteristics of low manufacturing cost, easy integration, simple and efficient detection method, and wide detection range, and has broad application prospects. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The real-time response test results of a molecularly imprinted device provided in the embodiments of this specification to target molecules of different concentrations are shown.

[0027] Figure 2 The linear relationship between the response values ​​of a molecularly imprinted device provided in the embodiments of this specification and different concentrations of target molecules is shown.

[0028] Figure 3 The results of response tests of a molecularly imprinted device and a NIP to different concentrations of target molecules provided in the embodiments of this specification are shown.

[0029] Figure 4 The selective test results of a molecularly imprinted device and a NIP provided in the embodiments of this specification are shown;

[0030] Figure 5 This specification illustrates a molecularly imprinted device used in an embodiment of the present specification for continuous recovery testing of target molecules at different concentrations;

[0031] Figure 6 This specification illustrates a molecular imprinting device provided in an embodiment of the present specification for continuous recovery testing of target molecules at the same concentration. Detailed Implementation

[0032] For the qualitative identification of gases in the field of research on aromatic molecular gases in hazardous solid waste, traditional gas detection methods are mostly aimed at volatile organic compounds (VOCs) with functional groups such as hydroxyl and carboxyl groups, and the detection temperature is above 150℃, which is complicated, energy-intensive and costly.

[0033] This specification provides a sensor prepared using molecularly imprinted materials as functional materials and conductive ink as basic materials. This sensor enables selective identification of aromatic hydrocarbon molecules in hazardous solid waste. Compared to the complex preparation methods currently used for volatile organic compounds (VOCs) sensors, the preparation method of the sensor provided in this specification is simpler, more convenient, and lower in cost. It can also detect a wider range of aromatic hydrocarbon molecules, achieving high-efficiency detection and thus reducing environmental pollution.

[0034] To make the objectives, technical solutions, and advantages of one or more embodiments of this specification clearer, the technical solutions of one or more embodiments of this specification will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of them. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of one or more embodiments of this specification.

[0035] The embodiments in this specification relate to a method for detecting aromatic gas molecules in hazardous solid waste. Molecularly imprinted materials are prepared using a precipitation polymerization method, and these materials are used as functional materials to prepare an electrochemical sensor, thereby achieving highly selective identification of aromatic molecules in hazardous solid waste.

[0036] Example 1: Preparation of aromatic molecularly imprinted materials

[0037] 4-Vinylpyridine (4-VP), ethylene glycol dimethacrylate (EGDMA), azobisisobutyronitrile (AIBN), and liquid aromatic molecules were added to a reaction vessel, and ultrasonication was used to promote uniform mixing of the substances. Then, nitrogen was used to degas the system to remove oxygen, ensuring that free radical-initiated polymerization could proceed smoothly. Finally, under nitrogen protection, thermally initiated polymerization was carried out to obtain aromatic molecularly imprinted material (MIP).

[0038] The liquid aromatic molecule can be one of toluene, ethylbenzene, xylene, or chlorobenzene. The xylene can be p-xylene, o-xylene, or m-xylene. Alternatively, the liquid aromatic molecule can be one of toluene, ethylbenzene, p-xylene, o-xylene, m-xylene, or chlorobenzene.

[0039] In this embodiment, 4-VP serves as the functional monomer, EGDMA as the crosslinking agent, AIBN as the initiator, and the liquid aromatic molecule as both the template molecule and the porogen. In the embodiments described herein, the liquid aromatic molecule simultaneously functions as both a template and a porogen.

[0040] Optionally, when the amount of liquid aromatic molecule used as template molecule and porogen is 20 mL, the amount of functional monomer 4-VP can be 1-4 mmol (e.g., 1 mmol), the amount of crosslinking agent EGDMA can be 1-4 mmol (e.g., 2 mmol), and the amount of initiator AIBN can be 3.3 mg. In this case, the reaction vessel can be a 100 mL round-bottom flask.

[0041] Optionally, the crosslinking agent EGDMA and the functional monomer 4-VP are subjected to vacuum distillation to remove the polymerization inhibitor before use.

[0042] Optionally, the initiator AIBN is purified by recrystallization from methanol before use.

[0043] Optionally, the duration of the mixed ultrasound can be, for example, about 15 minutes, and the duration of nitrogen degassing can be, for example, about 15 minutes.

[0044] Optionally, the reaction conditions for thermally initiated polymerization can be: oil bath at 80 to 110°C (e.g., 100°C), rotation speed at 40 to 70 r / min (e.g., 50 r / min), and reaction time at 12 to 36 h (e.g., 24 h).

[0045] It is understood that when the liquid aromatic molecule is toluene, toluene MIP is obtained; when the liquid aromatic molecule is ethylbenzene, ethylbenzene MIP is obtained; when the liquid aromatic molecule is p-xylene, p-xylene MIP is obtained; when the liquid aromatic molecule is m-xylene, m-xylene MIP is obtained; when the liquid aromatic molecule is o-xylene, o-xylene MIP is obtained; and when the liquid aromatic molecule is chlorobenzene, chlorobenzene MIP is obtained. The range of liquid aromatic molecules in the embodiments of this specification is not limited to the examples given herein.

[0046] The preparation process of the corresponding NIP is completely consistent with that of MIP, except that the components that play the roles of template molecules and porogens are replaced by acetonitrile solvent.

[0047] Example 2: Fabrication of interdigitated electrodes

[0048] In the embodiments of this specification, interdigitated electrodes are fabricated using vapor deposition. Specifically, interdigitated electrodes are fabricated by depositing metallic chromium and gold onto a flexible PET substrate using a vacuum thermal deposition method via a mask.

[0049] The overall size of the interdigital electrodes is controlled by a photomask. The overall size of the interdigital electrodes is 10×10mm, consisting of 8 pairs of electrodes, each pair being 7mm wide, with a spacing of 0.15mm between each pair.

[0050] The electrode materials are 10nm Cr and 100nm gold, and the use of Cr helps to increase the adhesion of Au.

[0051] Example 3: Preparation of a highly selective electrochemical sensor for aromatic hydrocarbon molecules

[0052] The MIP prepared in Example 1 was mixed and ground with conductive ink and organic molecular binder (e.g., in an agate mortar) to obtain a uniformly mixed slurry; the slurry was then coated onto the interdigitated electrode prepared in Example 2 by screen printing to obtain a highly selective electrochemical sensor for aromatic molecules.

[0053] MIP serves as a functional material, while conductive ink serves as both a basic material and a conductive agent.

[0054] The organic molecular binder may include a mixture of ethyl cellulose and terpineol. Optionally, the mass ratio of ethyl cellulose to terpineol may be 5:95.

[0055] Optionally, the mass ratio of MIP, conductive ink, and organic molecular binder can be 1:(5-60):(10-100), preferably 1:13:20. For example, 15mg of MIP, 0.2g of conductive ink, and 0.3g of organic molecular binder can be used.

[0056] In Example 3, the prepared highly selective electrochemical sensor for aromatic molecules can detect aromatic molecule gases at room temperature.

[0057] Example 4: Gas detection of aromatic hydrocarbon molecules in hazardous solid waste using a highly selective electrochemical sensor

[0058] In this specification, the electrochemical sensor device constructed in Example 3 is used to test for aromatic molecules in hazardous solid waste (e.g., gases such as toluene, ethylbenzene, or xylene).

[0059] Specifically, the static injection method can be used to conduct the test in the designed test chamber. As an example, the test chamber is made of steel with a volume of 200×200×200mm. There is a vent on the left side of the chamber and a sample inlet and a well-sealed wired circuit on the right side. An electric fan and a heating device are placed inside the chamber.

[0060] For device response characteristic testing, an example of the test procedure can be as follows: First, measure the baseline for 1 minute. After the device stabilizes, inject liquid solid aromatic hydrocarbon molecules (e.g., toluene, ethylbenzene, or p-xylene liquid) at a gas concentration equivalent to 10 ppm, and simultaneously record the device resistance change. When the resistance change tends to stabilize, open the chamber door to allow the gas to evaporate. The response magnitude is obtained according to the formula ΔR / R0×100 (ΔR=R-R0, where R0 is the device resistance at the end of the baseline, and R is the response value after 30 seconds).

[0061] Selective testing method: All tested gas concentrations are fixed at 10 ppm. After conversion to the corresponding liquid volume, the gas is injected into the chamber. The response time is fixed at 30 seconds. The change in resistance over time is recorded, and the response at 30 seconds is calculated for comparison. Note that after measuring one substance, the device needs to be restored to its original resistance value to avoid affecting subsequent measurements of other substances.

[0062] Example 5: Test Case

[0063] Taking p-xylene molecularly imprinted material (p-xylene MIP) as an example, 15 mg of p-xylene molecularly imprinted material, 0.2 g of conductive ink, and 0.3 g of organic molecular binder were weighed and ground in an agate mortar until the three were mixed evenly and there were no obvious particles. The evenly mixed slurry was then spread evenly on a screen printing screen to prepare a molecularly imprinted device (i.e., a highly selective molecularly imprinted electrochemical sensor for aromatic hydrocarbon molecules). The printed device was dried under vacuum at 80°C for 12 hours before use.

[0064] The fabricated device is then connected to a testing instrument for testing.

[0065] Figure 1The test was conducted in a sealed test chamber using a syringe to inject a series of different concentrations of p-xylene gas, namely 1 μL, 2 μL, 4 μL, 6 μL, 8 μL, and 10 μL. The response time was 30 seconds. Figure 1 (From 60s to 90s). It can be seen that within a 30s response time, the response value increases linearly with increasing concentration, indicating that the device has a good linear response. Simultaneously, it can be observed that the device recovers to its original state in a short time (10s, such as...). Figure 1 (From 90s to 100s). Test results show that the highly selective electrochemical sensor for aromatic molecules prepared in the examples of this specification requires only 30s for gas response and can recover to the original state of the sensor within 10s.

[0066] Figure 2 The linear relationship of the device's response values ​​under different concentration conditions is shown, R 2 It reached 0.98379.

[0067] Simultaneously, the response values ​​of MIP and NIP to xylene for the target molecular gas were compared. Figure 3 As can be seen, the response values ​​of MIP are all higher than those of NIP, indicating that we have successfully fabricated molecularly imprinted devices with high response values ​​and high sensitivity to target molecules.

[0068] Figure 4 The comparison of the response values ​​of the fabricated device to different gases is shown. It can be seen that the fabricated molecularly imprinted electrical sensor has the largest response value to xylene as the target molecule, and there is a clear distinction in response values ​​to other gases such as ethanol and acetonitrile. This indicates that we have successfully fabricated an electrical sensor with high selectivity for aromatic molecules, which can achieve specific recognition of aromatic molecules.

[0069] Figure 5 and Figure 6 The test demonstrated the response and recovery of the electrical sensor to target molecules of different and the same concentrations. It can be seen that the device can achieve a good recovery in a short time as the concentration increases. At the same time, the response values ​​of the device are basically at the same level in multiple consecutive tests of the same concentration of gas, indicating the stability and reproducibility of the device's response value. It has excellent electrical sensor performance and can be well applied to the detection of target molecules.

[0070] One or more embodiments of this specification provide a method for preparing and detecting a highly selective gas sensor for aromatic hydrocarbon molecules. During preparation, the sensor is fabricated by spin-coating or printing an aromatic hydrocarbon molecule-imprinted sensitive material and a semiconductor material onto interdigitated electrodes. During detection, after aromatic hydrocarbon molecules come into contact with the surface of the molecularly imprinted sensitive film, the state of the film changes, thereby altering the conductivity of the semiconductor material and causing a change in the sensor's resistance. The changes in resistance of each part can then be extracted using a 6.5-bit data acquisition system to acquire the response data of the aromatic hydrocarbon molecules.

[0071] Based on one or more embodiments of this specification, the detectable hazardous solid waste aromatic molecules are a class of environmental pollutants that are widely present in nature and have "three-way" toxicity. They mainly include monocyclic or polycyclic aromatic molecules and may be molecules that lack recognition sites.

[0072] Based on one or more embodiments of this specification, highly selective and sensitive detection of aromatic molecules in hazardous solid waste is achieved at room temperature, and different signal changes can be collected in 30 seconds, enabling rapid detection of aromatics analysis.

[0073] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than those shown in the embodiments and may still achieve the desired results.

[0074] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An aromatics molecule highly selective electrochemical sensor, characterized in that, The electrochemical sensor is prepared by using an aromatic hydrocarbon molecular imprinting material as a functional material and conductive ink as a basic material. The aromatic hydrocarbon molecular imprinting material is obtained by using one molecule selected from toluene, ethylbenzene, xylene or chlorobenzene as a template molecule and a porogen, using 4-vinylpyridine as a functional monomer, using ethylene glycol dimethacrylate as a crosslinking agent, using azobisisobutyronitrile as an initiator, removing the template molecule after reaction, and the like. The preparation method of the aromatic hydrocarbon molecular high-selectivity electrochemical sensor comprises the following steps: mixing, grinding and mixing the aromatic hydrocarbon molecular imprinting material, conductive ink and organic molecular binder to obtain a uniformly mixed slurry; and coating the slurry on an interdigital electrode by spin coating or screen printing to prepare the aromatic hydrocarbon molecular high-selectivity electrochemical sensor. The mass ratio of the aromatic hydrocarbon molecular imprinting material, the conductive ink and the organic molecular binder is 1:(5-60):(10-100), and the organic molecular binder comprises ethyl cellulose and terpineol.

2. The high-selectivity electrochemical sensor of aromatic hydrocarbons as claimed in claim 1, wherein, The preparation method of the aromatic hydrocarbon molecular imprinting material comprises the following steps: uniformly mixing the template molecule and the porogen, the functional monomer, the crosslinking agent and the initiator by ultrasonic mixing, introducing inert gas to remove oxygen, heat-initiating polymerization reaction in an inert gas environment, and obtaining the aromatic hydrocarbon molecular imprinting material after elution.

3. The high-selectivity electrochemical sensor of aromatic hydrocarbons as claimed in claim 2, wherein, The reaction conditions of the heat-initiated polymerization reaction comprise the following steps: oil bath at 80-110°C, rotation speed of 40-70 r / min, and reaction time of 12-36 h.

4. The high-selectivity electrochemical sensor for aromatic hydrocarbons according to claim 2, wherein The crosslinking agent and the functional monomer are respectively subjected to reduced pressure distillation treatment to remove the polymerization inhibitor before use. Alternatively, the initiator is subjected to methanol recrystallization treatment to achieve refinement before use.

5. The high-selectivity electrochemical sensor of aromatic hydrocarbons as claimed in claim 1, wherein, The interdigital electrode is prepared on a flexible substrate PET by a vacuum thermal deposition method through a mask.

6. Application of the aromatic hydrocarbon molecular high-selectivity electrochemical sensor of claim 1 in detection of hazardous solid waste aromatic hydrocarbon molecules.

7. The application of claim 6, wherein the hazardous solid waste aromatic hydrocarbon molecules comprise aromatic hydrocarbon molecules in liquid state at room temperature.

8. The application of claim 6, wherein the hazardous solid waste aromatic hydrocarbon molecules comprise monocyclic or polycyclic aromatic hydrocarbon molecules lacking recognition sites, and the recognition sites comprise hydroxyl, carboxyl or amino.

9. The application of claim 6, wherein the hazardous solid waste aromatic hydrocarbon molecules comprise toluene, ethylbenzene, xylene, naphthalene, chlorobenzene or nitrobenzene. ​ ​ ​

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