Gas sensitive material for detecting diacetylmorphine, gas sensor and preparation method

Abstract

The invention relates to a gas sensitive material for detecting diacetylmorphine, a gas sensor and a preparation method of the gas sensitive material, and the preparation method of the gas sensitive material comprises the following steps: taking zinc nitrate hexahydrate as a metal salt, and glycine and glucose as foaming raw materials, and foaming through a solution combustion method to obtain a ZnO nanosheet with a porous structure; the ZnO nanosheet is used as a gas sensitive material to prepare a gas sensor for detecting diacetylmorphine. The ZnO gas sensitive material provided by the embodiment of the invention has a relatively large specific surface area and a rich pore structure, effectively improves the gas sensitive performance of ZnO, and shows relatively high response to diacetylmorphine standard gas, ultrafast response capability and excellent stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas-sensitive elements, and particularly relates to a gas-sensitive material, a gas sensor for detecting diacetylmorphine, and a preparation method thereof. Background Art

[0002] In cases involving toxic substances, it is common to dissolve toxic substances in alcohol solutions (such as methanol and ethanol) to avoid inspection. Currently, common traditional detection methods include: liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, nuclear magnetic resonance spectroscopy, and electrochemistry. Traditional methods for detecting toxic substances usually require complex laboratory equipment and professional techniques, thus limiting their convenience and real-time performance in practical applications and being unable to meet the requirements of on-site rapid detection. Therefore, a rapid, reliable, convenient, and sensitive method for detecting toxic substances is needed.

[0003] In the fields of science and technology, gas sensors play a very crucial role and are widely used in environmental monitoring, medical diagnosis, food safety, and other fields. Currently, according to the known means of detecting toxic substances, the application of metal oxide semiconductor gas sensors to detect the toxic substance diacetylmorphine has not been reported.

[0004] Among them, ZnO, as a typical n-type semiconductor sensitive material, has characteristics such as chemical and thermal stability, environmental friendliness, high sensitivity, rapid response, and low cost, and has been widely studied. However, as a sensitive material, the gas-sensitive performance of ZnO is affected by various factors such as size, surface structure, and morphology, resulting in certain defects in sensitivity and selectivity when ZnO is used as a gas sensor in practical applications. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a gas-sensitive material, a gas sensor for detecting diacetylmorphine, and a preparation method thereof. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0006] The first embodiment of the present invention provides a preparation method of a gas-sensitive material for detecting diacetylmorphine, including:

[0007] Using zinc nitrate hexahydrate as a metal salt, glycine and glucose as foaming raw materials, and performing foaming by solution combustion method to obtain ZnO nanosheets with a porous structure; the ZnO nanosheets are used as a gas-sensitive material to prepare a gas sensor for detecting diacetylmorphine.

[0008] In an embodiment of the present invention, using zinc nitrate hexahydrate as a metal salt, glycine and glucose as foaming raw materials, and performing foaming by solution combustion method to obtain ZnO nanosheets with a porous structure, including:

[0009] Dissolve zinc nitrate hexahydrate, glycine, and glucose in water, and stir evenly to obtain a precursor solution;

[0010] Place the precursor solution in a muffle furnace at the target temperature and foam it by solution combustion method to obtain the foamed ZnO nanomaterial;

[0011] Place the ZnO nanomaterial in a muffle furnace at room temperature, heat it to the target temperature and keep it warm to completely oxidize the foamed ZnO nanomaterial to obtain the ZnO nanosheets.

[0012] In one embodiment of the present invention, dissolving zinc nitrate hexahydrate, glycine, and glucose in water and stirring evenly to obtain a precursor solution includes:

[0013] Dissolve 0.5 - 1.5 mmol of zinc nitrate hexahydrate, 13 - 15 mmol of glycine, and 6 - 8 mmol of glucose in 5 - 15 ml of water, and continuously stir at room temperature for 30 - 90 min to obtain the precursor solution.

[0014] In one embodiment of the present invention, placing the precursor solution in a muffle furnace at the target temperature and foaming it by solution combustion method to obtain the foamed ZnO nanomaterial includes:

[0015] Place the precursor solution in a muffle furnace at 400 - 600 °C and foam it by solution combustion method for 5 - 15 min to obtain the foamed ZnO nanomaterial.

[0016] In one embodiment of the present invention, placing the ZnO nanomaterial in a muffle furnace at room temperature, heating it to the target temperature and keeping it warm to completely oxidize the foamed ZnO nanomaterial to obtain the ZnO nanosheets includes:

[0017] Place the foamed ZnO nanomaterial in a muffle furnace at room temperature, heat it to 400 - 600 °C at a heating rate of 1 - 5 °C / min, and then keep it warm for 2 - 4 h to completely oxidize the foamed ZnO nanomaterial to obtain the ZnO nanosheets.

[0018] The second embodiment of the present invention provides a gas - sensitive material for detecting diacetylmorphine. The gas - sensitive material is a ZnO nanosheet with a porous structure prepared by the preparation method described in the above - mentioned embodiment. The ZnO nanosheets are used to prepare a gas sensor for detecting diacetylmorphine.

[0019] The third embodiment of the present invention provides a preparation method of a gas sensor for detecting diacetylmorphine, including the steps:

[0020] The gas-sensitive material described in the above embodiment is ground and mixed with absolute ethanol to form a paste-like sensitive material;

[0021] The paste-like sensitive material is coated on the outer surface of the ceramic tube to form a ZnO nanosheet sensitive reaction layer;

[0022] The ceramic tube coated with the ZnO nanosheet sensitive reaction layer is placed in a muffle furnace for aging;

[0023] The heating wire is placed inside the ceramic tube, and both ends of the heating wire and the four pins of the ceramic tube are welded on a hexagonal base to obtain a ZnO nanosheet gas sensor.

[0024] The fourth embodiment of the present invention provides a gas sensor for detecting diacetylmorphine, which is prepared by the preparation method described in the above embodiment, and includes: a ceramic tube, a ZnO nanosheet sensitive reaction layer, a heating wire and a hexagonal base, wherein the ZnO nanosheet sensitive reaction layer is coated on the outer surface of the ceramic tube, the heating wire is located inside the ceramic tube, and both ends of the heating wire and the four pins of the ceramic tube are welded on the hexagonal base.

[0025] The fifth embodiment of the present invention provides a method for detecting diacetylmorphine gas by a gas sensor, including the steps of:

[0026] The diacetylmorphine standard solution is placed in a test cavity, and a diacetylmorphine standard gas environment is formed in the test cavity by using the static liquefied gas distribution method;

[0027] The ZnO nanosheet gas sensor described in the above embodiment is placed in the diacetylmorphine standard gas environment for a period of time, and the test response resistance value of the ZnO nanosheet gas sensor is recorded;

[0028] The sensitive response value of the ZnO nanosheet gas sensor to diacetylmorphine is calculated by using the test response resistance value and the baseline resistance value, wherein the baseline resistance value is obtained by placing the ZnO nanosheet gas sensor in the background gas environment of the standard solution for a period of time, and the standard solution includes an alcohol solution.

[0029] In an embodiment of the present invention, the sensitive response value of the ZnO nanosheet gas sensor to diacetylmorphine is: Response = R g / R m where R g is the test response resistance value, and R m is the baseline resistance value.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. The present invention prepares a ZnO gas-sensitive material with a nanosheet morphology by foaming zinc nitrate hexahydrate, glycine, and glucose through a solution combustion method. This material has a large specific surface area and a rich pore structure, effectively improving the gas-sensing performance of ZnO. It shows a high response to diacetylmorphine standard gas, an ultra-fast response ability, and excellent stability.

[0032] 2. The gas sensor of the present invention is optimized for diacetylmorphine-related gases, can effectively distinguish other interfering gases, and has high sensitivity and selectivity. It can respond quickly and give a detection result within seconds, which is suitable for rapid judgment in emergency situations. It has a miniaturized design, is easy to carry, and is suitable for law enforcement officers and on-site detection.

[0033] 3. The detection method of diacetylmorphine gas in the present invention utilizes the characteristics of the metal oxide semiconductor ZnO, combines the unique odor characteristics of diacetylmorphine in volatile organic compounds, and obtains the detection result of the special odor generated by diacetylmorphine by observing the change in the test response resistance value and the baseline resistance value of the sensor, which has the advantages of being fast, accurate, and convenient. Description of the Drawings

[0034] Figure 1 It is a schematic flow chart of a preparation method of a gas-sensitive material for detecting diacetylmorphine provided by an embodiment of the present invention;

[0035] Figure 2 It is a schematic diagram of a detection method of a gas sensor for diacetylmorphine gas provided by an embodiment of the present invention;

[0036] Figure 3 It is a scanning electron microscope image of the sensitive material ZnO nanosheet provided by an embodiment of the present invention;

[0037] Figure 4 It is an X-ray diffraction pattern of the sensitive material ZnO nanosheet provided by an embodiment of the present invention;

[0038] Figure 5 It is a schematic diagram of the response value of a ZnO gas sensor to 100 ppm diacetylmorphine standard gas at different working temperatures provided by an embodiment of the present invention;

[0039] Figure 6 It is a real-time resistance change diagram of a ZnO gas sensor to diacetylmorphine standard gases with different concentrations (5 - 150 ppm) provided by an embodiment of the present invention;

[0040] Figure 7 It is a linear relationship diagram between the response and concentration of a ZnO gas sensor to diacetylmorphine standard gas provided by an embodiment of the present invention;

[0041] Figure 8 Response value graph of the ZnO gas sensor provided by the embodiment of the present invention to different toxic substances;

[0042] Figure 9 Schematic diagram of the response / recovery time of the ZnO gas sensor provided by the embodiment of the present invention to 100 ppm diacetylmorphine standard gas;

[0043] Figure 10 Stability sensitivity test graph of the ZnO gas sensor provided by the embodiment of the present invention to diacetylmorphine standard gas. Detailed implementation manners

[0044] The present invention will be further described in detail below in conjunction with specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0045] Embodiment 1

[0046] This embodiment provides a preparation method of a gas-sensitive material for detecting diacetylmorphine. In this preparation method, zinc nitrate hexahydrate is used as the metal salt, and glycine and glucose are used as the foaming raw materials. Through a simple solution combustion method, ZnO nanosheets with a rich pore structure are quickly foamed, and the ZnO nanosheets are used as a gas-sensitive material to prepare a gas sensor for detecting diacetylmorphine.

[0047] Please refer to Figure 1 , Figure 1 Schematic flow chart of a preparation method of a gas-sensitive material for detecting diacetylmorphine provided by the embodiment of the present invention. This preparation method includes the steps:

[0048] S1. Dissolve zinc nitrate hexahydrate, glycine and glucose in water and stir evenly to obtain a precursor solution.

[0049] Specifically, dissolve 0.5 - 1.5 mmol of zinc nitrate hexahydrate, 13 - 15 mmol of glycine and 6 - 8 mmol of glucose in 5 - 15 ml of water, and continuously stir at room temperature for 30 - 90 min to obtain a uniform precursor solution.

[0050] S2. Place the precursor solution in a muffle furnace at the target temperature and foam it by the solution combustion method to obtain the foamed ZnO nanomaterial.

[0051] Specifically, first heat the muffle furnace to the target temperature, and the target temperature is 400 - 600 °C; then place the precursor solution obtained in step S1 in a crucible and place it in a muffle furnace at 400 - 600 °C to quickly foam by solution combustion for 5 - 15 min to obtain the foamed ZnO nanomaterial.

[0052] Exemplarily, the heating rate of the muffle furnace is 10 °C / min, the target temperature is 500 °C, and the foaming time is 10 min.

[0053] In this embodiment, glycine and glucose are used as foaming raw materials. During the solution combustion process, the Maillard reaction occurs between glycine and glucose, generating a large number of bubbles, thereby achieving the foaming effect.

[0054] S3. Place the ZnO nanomaterial in a muffle furnace at room temperature, heat it to the target temperature and keep it warm to completely oxidize the foamed ZnO nanomaterial to obtain ZnO nanosheets.

[0055] Specifically, place the foamed ZnO nanomaterial in step S2 in a muffle furnace at room temperature, heat it to 400 - 600 °C at a heating rate of 1 - 5 °C / min, and then keep it warm for 2 - 4 h to completely oxidize the foamed ZnO nanomaterial to obtain ZnO nanosheets.

[0056] Exemplarily, place the foamed ZnO nanomaterial in a muffle furnace at room temperature, heat it to 500 °C at a heating rate of 1 °C / min, and then keep it warm for 3 h to completely oxidize the foamed ZnO nanomaterial to obtain ZnO nanosheets.

[0057] This embodiment also provides a gas-sensitive material for detecting diacetylmorphine. The gas-sensitive material is the ZnO nanosheet with a rich pore structure prepared by the above preparation method.

[0058] In this embodiment, zinc nitrate hexahydrate, glycine, and glucose are rapidly foamed by the solution combustion method to prepare a ZnO gas-sensitive material with a nanosheet morphology. The ZnO gas-sensitive material has a large specific surface area and a rich pore structure, which can provide more active adsorption sites for the gas-sensing reaction process, facilitating the generation of more oxygen adsorption species (O - , O 2 - and O 2- ), effectively improving the sensitive performance of ZnO to the target detection gas, showing a high response, an ultra-fast response ability, and excellent stability to the diacetylmorphine standard gas.

[0059] Example Two

[0060] This embodiment provides a preparation method of a gas sensor for detecting diacetylmorphine. The preparation method includes the steps:

[0061] S1. Grind and mix the gas-sensitive material with absolute ethanol to form a paste-like sensitive material.

[0062] Specifically, the ZnO nanosheet sensitive material of Example 1 and an appropriate amount of absolute ethanol are placed in a mortar and ground and mixed to form a uniform paste-like sensitive material.

[0063] S2. The paste-like sensitive material is applied to the outer surface of the ceramic tube to form a ZnO nanosheet sensitive reaction layer.

[0064] Specifically, a small brush is used to evenly apply the paste-like sensitive material on the outer surface of the ceramic tube to form a uniform ZnO nanosheet sensitive reaction.

[0065] S3. The ceramic tube coated with the ZnO nanosheet sensitive reaction layer is placed in a muffle furnace for aging.

[0066] Specifically, the prepared ceramic tube coated with the ZnO nanosheet sensitive reaction layer is placed in a muffle furnace and aged at 200 °C for 1 h.

[0067] S4. A heating wire is placed inside the ceramic tube, and both ends of the heating wire and the four pins of the ceramic tube are welded to a hexagonal base to obtain a ZnO nanosheet gas sensor.

[0068] Specifically, a heating wire (resistance: 20 - 50 kΩ) is placed inside the ceramic tube, and the working temperature of the sensor is controlled by changing the current flowing through the heating wire. Then both ends of the heating wire and the four pins of the ceramic tube are welded to the hexagonal base to complete the preparation of the gas sensor for detecting the toxic substance diacetylmorphine.

[0069] An embodiment of the present invention also provides a gas sensor for detecting diacetylmorphine. The gas sensor is prepared by the above preparation method and includes: a ceramic tube, a ZnO nanosheet sensitive reaction layer, a heating wire, and a hexagonal base. Among them, the ZnO nanosheet sensitive reaction layer is coated on the outer surface of the ceramic tube, the heating wire is located inside the ceramic tube, and both ends of the heating wire and the four pins of the ceramic tube are welded to the hexagonal base.

[0070] The gas sensor of this embodiment utilizes the characteristics of the metal oxide semiconductor ZnO, combines the unique odor characteristics of diacetylmorphine among volatile organic compounds, is optimized for diacetylmorphine-related gases, can effectively distinguish other interfering gases, and has high sensitivity and selectivity; it can respond quickly and give a detection result within seconds, suitable for rapid judgment in emergency situations; it has a miniaturized design, is easy to carry, and is suitable for law enforcement officers and on-site detection use.

[0071] Example 3

[0072] Please refer to Figure 2 , Figure 2Schematic diagram of a method for detecting diacetylmorphine gas by a gas sensor provided in an embodiment of the present invention. The method for detecting diacetylmorphine gas by the gas sensor includes the steps:

[0073] S1. Place a diacetylmorphine standard solution in a test cavity, and form a diacetylmorphine standard gas environment in the test cavity by using a static liquefied gas distribution method.

[0074] Specifically, use a micro syringe to place a certain amount of diacetylmorphine standard solution in the test cavity, and form a diacetylmorphine standard gas atmosphere in the test cavity by using a static liquefied gas distribution method.

[0075] Among them, the standard solution includes an alcohol solution, for example, methanol or ethanol. Exemplarily, the diacetylmorphine standard solution is a solution of diacetylmorphine dissolved in methanol, and the concentration can be 1 ng / ml.

[0076] The target gas concentration obtained by using the static liquefied gas distribution method is:

[0077]

[0078] Among them, C (ppm), ρ (g / ml), M (g / mol), V 1 (μl) and V 2 (L) are the target gas concentration, liquid density, liquid purity, liquid molecular weight, liquid volume and test chamber volume (1 L) respectively. Since the content of diacetylmorphine in the diacetylmorphine standard solution is extremely low, the specific concentration is quantified according to the volume of methanol during testing.

[0079] S2. Place the ZnO nanosheet gas sensor in the diacetylmorphine standard gas environment for a period of time, and record the test response resistance value of the ZnO nanosheet gas sensor.

[0080] Specifically, place the ZnO nanosheet gas sensor in the diacetylmorphine standard gas environment, and after stabilizing for 3-5 min, record the test response resistance value of the sensor as R g .

[0081] S3. Calculate the sensitive response value of the ZnO nanosheet gas sensor to diacetylmorphine by using the test response resistance value and the baseline resistance value, where the baseline resistance value is obtained by placing the ZnO nanosheet gas sensor in the background gas environment of the standard solution for a period of time, and the standard solution includes an alcohol solution.

[0082] Specifically, the method for obtaining the baseline resistance value is: first place the ZnO nanosheet gas sensor in an air environment, and after stabilizing for a period of time, record the resistance value of the sensor as R aThen, place the ZnO nanosheet gas sensor in the background gas environment of the standard solution for a period of time, and record the baseline resistance value of the sensor. Taking the standard solution as methanol solution as an example, place the ZnO nanosheet gas sensor in the methanol background gas environment. After stabilizing for 3 - 5 min, record the baseline resistance value of the sensor as R m 。

[0083] The sensitive response value of the ZnO nanosheet gas sensor to diacetylmorphine is: Response = R g / R m ,wherein, R g is the test response resistance value, and R m is the baseline resistance value.

[0084] The detection method of diacetylmorphine gas in the present invention utilizes the characteristics of metal oxide semiconductor ZnO, combines the unique odor characteristics of diacetylmorphine in volatile organic compounds, and obtains the detection result of the special odor generated by diacetylmorphine by observing the changes in the test response resistance value and the baseline resistance value of the sensor, which has the advantages of fast, accurate, convenient, low - cost and real - time monitoring.

[0085] Example 4

[0086] Based on Example 1, Example 2 and Example 3, this example illustrates the preparation method of the gas - sensitive material for detecting diacetylmorphine, the preparation method of the gas sensor, and the detection method of diacetylmorphine gas through the following examples.

[0087] Step 1: Using zinc nitrate hexahydrate as the metal salt, glycine and glucose as the foaming raw materials, ZnO nanosheets with a rich pore structure are rapidly foamed by a simple solution combustion method. Specifically, it includes:

[0088] Step 1.1: Dissolve 1 mmol of zinc nitrate hexahydrate, 14 mmol of glycine and 7 mmol of glucose in 10 ml of deionized water, and continuously stir at room temperature for 60 min to obtain a uniform precursor solution.

[0089] Step 1.2: Heat the muffle furnace to the target temperature of 500 °C at a heating rate of 10 °C / min.

[0090] Step 1.3: Place the uniform precursor solution in a crucible, and put it into the muffle furnace at 500 °C for rapid solution combustion foaming for 10 min to obtain the foamed ZnO nanomaterial.

[0091] Step 1.4: Place the ZnO nanomaterials obtained by foaming in a muffle furnace at room temperature, heat them to 500 °C at a heating rate of 1 °C / min, then keep them at this temperature for 3 h to completely oxidize the nanosheets obtained by rapid foaming into ZnO, thus obtaining ZnO nanosheets.

[0092] Please refer to Figure 3 , Figure 3 which is the scanning electron microscope image of the ZnO nanosheets, the sensitive material provided by the embodiment of the present invention. It can be Figure 3 observed that the microscopic morphology of ZnO presents a nanosheet layer structure. This nanosheet layer structure will bring a large specific surface area, providing more active adsorption sites for the occurrence of the gas-sensing reaction, thereby improving the response of the sensor to the target gas. In addition, it can be found that there are a large number of pore structures in the nanosheets, and this structure will accelerate the transmission of the target gas and speed up the occurrence of the gas-sensing reaction.

[0093] Please refer to Figure 4 , Figure 4 which is the X-ray diffraction pattern of the ZnO nanosheets, the sensitive material provided by the embodiment of the present invention. Figure 4 In , the diffraction peaks of the sample match the standard card JCPDS NO.36-1451, indicating that the prepared sensitive material is relatively pure and there are no peaks of other impurity elements.

[0094] Step 2: Use the ZnO nanosheets prepared in Step 1 as the sensitive material, and adopt the lateral heating device process to coat, assemble and weld the sensitive material to complete the preparation of a gas sensor for detecting the toxic substance diacetylmorphine. Specifically, it includes:

[0095] Step 2.1: Place the ZnO nanosheet sensitive material and an appropriate amount of absolute ethanol in a mortar and grind and mix them to form a uniform paste-like sensitive material.

[0096] Step 2.2: Use a small brush to evenly apply the paste-like sensitive material on the outer surface of the ceramic tube to form a uniform ZnO nanosheet sensitive reaction layer.

[0097] Step 2.3: Place the ceramic tube coated with the ZnO nanosheet sensitive reaction layer prepared in a muffle furnace and age it at 200 °C for 1 h.

[0098] Step 2.4: Place a heating wire (resistance: 20 - 50 kΩ) inside the ceramic tube, and control the working temperature of the sensor by changing the current flowing through the heating wire. Then weld the two ends of the heating wire and the four pins of the ceramic tube on a hexagonal base to complete the preparation of a gas sensor for detecting the toxic substance diacetylmorphine.

[0099] Step 3: The prepared ZnO nanosheet gas sensor is used to perform a gas-sensing reaction test on a diacetylmorphine standard gas (diacetylmorphine is dissolved in a methanol solution with a concentration of 100 ng / mL).

[0100] Step 3.1: Place the prepared ZnO nanosheet gas sensor in an air environment. After stabilizing for 5 min, record the resistance value of the sensor as R a ;

[0101] Step 3.2: Place the ZnO nanosheet gas sensor in a methanol background gas environment. After stabilizing for 5 min, record the baseline resistance value of the sensor as R m .

[0102] Step 3.3: Use a microsyringe to place a certain amount of the diacetylmorphine standard solution into the test cavity, and a diacetylmorphine standard gas atmosphere is formed in the test cavity. Then place the ZnO nanosheet gas sensor in the diacetylmorphine standard gas environment. After stabilizing for a period of time, record the measured response resistance value of the sensor as R g .

[0103] Step 3.4: Define the response value of the ZnO nanosheet gas sensor to the sensitive response of diacetylmorphine as: Response = R g / R m .

[0104] Please refer to Figure 5 , Figure 5 , which is a schematic diagram of the response values of the ZnO gas sensor provided by the embodiment of the present invention to 100 ppm diacetylmorphine standard gas at different working temperatures. It can be found from Figure 5 that the optimal working temperature of the sensor is 400 °C.

[0105] Please refer to Figure 6 , Figure 6 , which is a real-time resistance change diagram of the ZnO gas sensor provided by the embodiment of the present invention to diacetylmorphine standard gases with different concentrations (5 - 150 ppm). It can be clearly seen from Figure 6 that the sensor shows significantly changing signals, a wide detection range, and a low detection limit for diacetylmorphine at different concentrations, bringing great potential for the ZnO gas sensor to detect toxic substances.

[0106] Please refer to Figure 7 , Figure 7 , which is a linear relationship diagram between the response and concentration of the ZnO gas sensor provided by the embodiment of the present invention to the diacetylmorphine standard gas. Figure 7 It shows that the good linear relationship indicates that the ZnO gas sensor has the ability to monitor diacetylmorphine standard gases at different concentrations in real time.

[0107] Please refer to Figure 8 , Figure 8 which is the response value graph of the ZnO gas sensor provided by the embodiment of the present invention to different toxic substances. Figure 8 It shows that the sensor has good selectivity to the diacetylmorphine standard gas and can accurately identify diacetylmorphine.

[0108] Please refer to Figure 9 , Figure 9 which is the schematic diagram of the response / recovery time of the ZnO gas sensor provided by the embodiment of the present invention to 100 ppm diacetylmorphine standard gas. Among them, the response time is 2 s and the recovery time is 1 s, Figure 9 indicating that the fast recognition ability is also a very important index for practical applications.

[0109] Please refer to Figure 10 , Figure 10 which is the stability sensitivity test graph of the ZnO gas sensor provided by the embodiment of the present invention to the diacetylmorphine standard gas. The ZnO sensor is continuously tested by switching between the background gas of the standard solution and the diacetylmorphine standard gas environment for multiple times, indicating that the ZnO gas sensor has good stability to the diacetylmorphine standard gas.

[0110] Through the above experimental data analysis, the ZnO sensitive material prepared by the simple preparation method in this embodiment exhibits excellent detection performance for the diacetylmorphine standard gas. By deeply studying the application of metal oxide semiconductor gas sensors in the detection of diacetylmorphine, it is expected to develop an efficient and reliable diacetylmorphine detection system.

[0111] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing a gas sensitive material for detecting diacetylmorphine, characterized in that: include: Zinc nitrate hexahydrate is used as a metal salt, glycine and glucose are used as foaming raw materials, and foaming is performed through a solution combustion method to obtain a ZnO nanosheet with a porous structure; the ZnO nanosheet is used as a gas sensitive material to prepare a gas sensor for detecting diacetylmorphine.

2. The method for preparing a gas sensitive material for detecting diacetylmorphine according to claim 1, characterized in that: Using zinc nitrate hexahydrate as metal salt, glycine and glucose as foaming raw materials, foaming is performed by solution combustion method to obtain ZnO nanosheets with a porous structure, including: Dissolving zinc nitrate hexahydrate, glycine and glucose in water and stirring to obtain a precursor solution; The precursor solution is placed in a muffle furnace at a target temperature and foamed by a solution combustion method to obtain a foamed ZnO nanomaterial; The ZnO nanomaterial is placed in a muffle furnace at room temperature, and the temperature is raised to the target temperature and maintained to completely oxidize the foamed ZnO nanomaterial to obtain the ZnO nanosheet.

3. The method for preparing a gas sensitive material for detecting diacetylmorphine according to claim 2, characterized in that: Dissolve zinc nitrate hexahydrate, glycine and glucose in water and stir evenly to obtain a precursor solution, including: 0.5-1.5 mmol zinc nitrate hexahydrate, 13-15 mmol glycine and 6-8 mmol glucose are dissolved in 5-15 ml water, and stirred continuously for 30-90 min at room temperature to obtain the precursor solution.

4. The method for preparing a gas sensitive material for detecting diacetylmorphine according to claim 2, characterized in that: The precursor solution is placed in a muffle furnace at a target temperature and foamed by a solution combustion method to obtain a foamed ZnO nanomaterial, comprising: The precursor solution is placed in a muffle furnace at 400-600° C. and foamed for 5-15 minutes by a solution combustion method to obtain the foamed ZnO nanomaterial.

5. The method for preparing a gas sensitive material for detecting diacetylmorphine according to claim 2, characterized in that: The ZnO nanomaterial is placed in a muffle furnace at room temperature, and the temperature is raised to the target temperature and kept warm to completely oxidize the foamed ZnO nanomaterial to obtain the ZnO nanosheet, comprising: The foamed ZnO nanomaterial is placed in a muffle furnace at room temperature, heated to 400-600° C. at a heating rate of 1-5° C. / min, and then kept warm for 2-4 hours to completely oxidize the foamed ZnO nanomaterial to obtain the ZnO nanosheet.

6. A gas sensitive material for detecting diacetylmorphine, characterized in that: The gas sensitive material is a ZnO nanosheet with a porous structure prepared by the preparation method according to any one of claims 1 to 5, and the ZnO nanosheet is used to prepare a gas sensor for detecting diacetylmorphine.

7. A method for preparing a gas sensor for detecting diacetylmorphine, characterized in that: Includes steps: Grinding and mixing the gas sensitive material according to claim 6 with anhydrous ethanol to form a paste-like sensitive material; Applying the paste-like sensitive material on the outer surface of the ceramic tube to form a ZnO nanosheet sensitive reaction layer; The ceramic tube coated with the sensitive reaction layer of ZnO nanosheets is placed in a muffle furnace for aging; A heating wire is placed inside a ceramic tube, and two ends of the heating wire and four pins of the ceramic tube are welded to a hexagonal base to obtain a ZnO nanosheet gas sensor.

8. A gas sensor for detecting diacetylmorphine, characterized in that: The method according to claim 7 comprises: a ceramic tube, a ZnO nanosheet sensitive reaction layer, a heating wire and a hexagonal base, wherein the ZnO nanosheet sensitive reaction layer is coated on the outer surface of the ceramic tube, the heating wire is located inside the ceramic tube, and the two ends of the heating wire and the four pins of the ceramic tube are welded to the hexagonal base.

9. A method for detecting diacetylmorphine gas using a gas sensor, characterized in that: Includes steps: placing a diacetylmorphine standard solution in a test cavity, and forming a diacetylmorphine standard gas environment in the test cavity by using a static liquefied gas distribution method; Placing the ZnO nanosheet gas sensor of claim 8 in the diacetylmorphine standard gas environment for a period of time, and recording the test response resistance value of the ZnO nanosheet gas sensor; The sensitive response value of the ZnO nanosheet gas sensor to diacetylmorphine is calculated using the baseline resistance value and the test response resistance value, wherein the baseline resistance value is obtained by placing the ZnO nanosheet gas sensor in a background gas environment of a standard solution for a period of time, and the standard solution includes an alcohol solution.

10. The method for detecting diacetylmorphine gas using a gas sensor according to claim 9, characterized in that: The sensitive response value of the ZnO nanosheet gas sensor to diacetylmorphine is: Response = R g / R m , where R g To test the response resistance value, R m is the baseline resistance value.

Images