Design method and detection application of tea volatile pheromone gas sensor

Abstract

The present application relates to tea volatile pheromone gas sensor technical field, specifically to a kind of tea volatile pheromone gas sensor design method and detection application, its preparation Ru@ZnO sensitive film, mainly by Ru and ZnO composition.Ru@ZnO sensitive film is dispersed in a small amount of anhydrous ethanol by being then brushed on electrode by brush, and air-dried in 60-80 ℃ oven, and the tea aroma sensor constructed is used when gas sensitive test.This tea aroma sensor based on Ru@ZnO sensitive film designed by the present application can realize the rapid detection of tea aroma leaf alcohol, and show excellent gas sensitive characteristics, provide research basis and implementation approach for the application of sensor in tea quality evaluation and tea plant disease and pest monitoring.

Description

Technical Field

[0001] This invention relates to the field of tea tree volatile pheromone gas sensor technology, specifically to a design method and detection application of a tea tree volatile pheromone gas sensor. Background Technology

[0002] Tea buds, the tender shoots of the tea plant, are rich in essential nutrients and are the main raw material for tea beverage production. However, tea buds are susceptible to pests and diseases, which can severely affect yield and quality. Previous studies have shown that when tea plants are attacked by pests or diseases, various volatile organic compounds (VOCs), including leaf alcohol, decanal, linalool, phenethyl alcohol, farnesene, ocimene, geraniol, n-octanol, benzaldehyde, and leaf alcohol acetate, are induced and significantly increased. Currently, these VOCs are usually detected using traditional methods, such as gas chromatography-mass spectrometry (GC-MS). Although GC-MS is considered the gold standard, it has significant drawbacks, including high cost, lengthy analysis time, and the need for extensive sample preparation and skilled operators. In recent years, VOCs have become an effective means of detecting and diagnosing tea pests and diseases. Researchers have studied various types of sensors in order to more effectively detect these VOCs. Metal oxide semiconductor-based gas sensors are widely used to detect volatile organic compounds due to their advantages such as stability, cost-effectiveness, small size, and fast response speed, and are applied in fields such as environmental monitoring, industrial production, and healthcare.

[0003] In recent years, ZnO, as an important N-type semiconductor material, has gradually gained widespread attention in various fields due to its excellent chemical and thermal stability. Gas sensors fabricated using ZnO materials have become a current research hotspot. Meanwhile, the modification treatment with the noble metal ruthenium has been widely applied to ZnO gas sensors to improve their gas-sensing performance. As a noble metal, ruthenium can effectively enhance the electronic structure and surface reactivity of zinc oxide, thereby improving the sensor's response speed, sensitivity, and selectivity. This modification method can improve the stability of ZnO materials under high temperatures and complex atmospheres, giving it better performance in practical applications. Currently, the application of noble metal-modified ZnO nanomaterials in the field of tea pest and disease detection has not been fully studied and reported. To address this gap, we developed a gas-sensing element for the rapid detection of ten gases in tea aroma volatiles and systematically studied the sensor's performance and characteristics. This sensor can not only effectively assess the quality of tea but also monitor the status of tea pests and diseases in real time, showing significant application potential. Summary of the Invention

[0004] The purpose of this invention is to provide a design method and detection application for a tea tree volatile pheromone gas sensor. The Ru@ZnO sensitive film and its preparation method provided by this invention, as well as the rapid detection of tea aroma substances, have excellent gas-sensing characteristics for tea volatile substances.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for designing a volatile pheromone gas sensor for tea trees includes the following steps:

[0007] Step A: Dissolve zinc nitrate hexahydrate in deionized water to form solution A; dissolve 2-methylimidazole in deionized water to obtain solution B;

[0008] Mix solutions A and B to obtain a mixture. Quickly add a 29% (w / w) ammonia solution to the mixture and stir for 2-4 hours.

[0009] Step B: After the chemical precipitation is complete, transfer the suspension to a 50mL centrifuge tube, use ethanol to centrifuge and wash the precipitate, and dry it to obtain the first dry sample.

[0010] Step C: Calcine the first dried sample to obtain a cake-shaped ZnO sensitive thin film material;

[0011] Step D: Immerse the ZnO sensitive film material in deionized water; then add potassium hexachlororuthenate, stir, and dry overnight to obtain a second dried sample. Calcine the second dried sample to obtain the Ru@ZnO sensitive film.

[0012] As a further aspect of the present invention: in step A, the molar ratio of zinc nitrate hexahydrate, 2-methylimidazole, and ammonia solution with a mass fraction of 29% is 1-2.7 mmol: 11-30 mmol: 15.5-36 mL.

[0013] As a further aspect of the present invention: in step B, the centrifugation speed is set to 6000-10000 rpm, and the centrifugation time is 5-10 min.

[0014] As a further aspect of the present invention: in step B, the drying temperature is 60-80℃ and the drying time is 6-48h.

[0015] As a further aspect of the present invention: in step C, the calcination temperature is 300-700℃ and the calcination time is 1-4h.

[0016] As a further aspect of the present invention: in step C, the heating rate of calcination is 1-20℃ / min.

[0017] As a further aspect of the present invention: in step D, the calcination conditions are: calcination at 200-400°C in an atmosphere containing H2 / Ar for 1 hour.

[0018] As a further aspect of the present invention: in step D, the calcination heating rate is 2°C / min. -1 .

[0019] As a further aspect of the present invention, the mass ratio of ZnO sensitive thin film material to potassium hexachlororuthenate is 10-50:1.

[0020] An application of a tea tree volatile pheromone gas sensor includes the following steps:

[0021] Zinc oxide material is dispersed in a small amount of ethanol, then brushed onto the electrode, air-dried, and then dried in an oven at 60-80℃ for use in gas-sensitive testing.

[0022] The beneficial effects of this invention are:

[0023] This invention utilizes ZnO as a precursor, and through processes such as noble metal anchoring followed by annealing in an H2 / Ar atmosphere, prepares composite nanomaterials. These nanomaterials are then fabricated using sensor-sensitive thin film construction processes such as brush coating to create a tea aroma sensor, achieving a rapid sensing response to leaf alcohols and exhibiting excellent gas-sensing characteristics. The Ru@ZnO sensitive thin film prepared by this invention has the following advantages:

[0024] The Ru@ZnO sensitive film provided by this invention can be directly used as a gas-sensitive material for gas-sensing research on leaf alcohol, a volatile substance in tea.

[0025] The method for preparing Ru@ZnO sensitive films provided by this invention only requires common laboratory equipment and does not require special equipment. The process is simple and easy to operate.

[0026] The present invention provides a Ru@ZnO sensitive film that can be prepared with high sensitivity, stability and reproducibility. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0028] Figure 1 The image shown is a SEM image of a Ru@ZnO sensitive thin film material sample obtained in the present invention. It is a Ru@ZnO material sample obtained by Ru anchoring at a calcination temperature of 500°C.

[0029] Figure 2 XRD images of Ru@ZnO sensitive films provided in embodiments of the present invention;

[0030] Figure 3 The image shows the C1s of the Ru@ZnO material sample obtained in the present invention, which is a zinc oxide material anchored with 6 mg Ru content.

[0031] Figure 4 The gas-sensitivity test response (Rgas / Rair)-Time(s) curve of zinc oxide material anchored with 6 mg Ru at a working temperature of 225°C is shown in this embodiment of the invention.

[0032] Figure 5 The following is a gas-sensing test (Rgas / Rair)-Time(s) curve of Ru@ZnO sensitive film prepared by calcination at 500°C in air atmosphere and anchoring with Ru, at a working temperature of 225°C, for leaf alcohol, phenethyl alcohol, decanal, linalool, phenethyl alcohol, farnesene, ocimene, geraniol, n-octanol, benzaldehyde and leaf alcohol acetate. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] Example 1

[0035] This invention provides a design method for a tea tree volatile pheromone gas sensor, comprising the following steps:

[0036] Step A: Dissolve zinc nitrate hexahydrate (1 mmol, Zn(NO3)2·6H2O) in 55 mL of deionized water to form solution A; Separately, dissolve 2-methylimidazole (11 mmol, MeIM) in 20 mL of deionized water and stir magnetically until the solution becomes clear to obtain solution B.

[0037] Solution A and solution B were mixed to obtain a mixture. 15.5 mL of a 29% ammonia solution was quickly added to the mixture, and then the mixture was magnetically stirred at 600 rpm for 2 hours at room temperature.

[0038] Step B: After chemical precipitation, transfer the suspension to a 50 mL centrifuge tube. Then, wash the precipitate three times with ethanol by centrifugation to collect a clean precipitate. The centrifuge speed is set to 6000 rpm for 5 minutes. Next, dry the precipitate at 60°C for 6 hours to remove moisture and ethanol from the sample, obtaining a dried sample.

[0039] Step C: Calcine the obtained dried sample at 300℃ for 1 hour (heating rate of 1℃ / min) to finally obtain a cake-shaped ZnO sensitive thin film material.

[0040] Step D: Immerse 0.05 g of the prepared ZnO sensitive film material in 5 mL of deionized water; magnetically stir at 6000-10000 rpm at room temperature; then add 0.001 g of potassium hexachlororuthenate (III) (K3(RuCl6). Stir the mixture at room temperature for 24 hours. After stirring, dry the sample at 60 °C overnight; finally, calcine the dried material at 200 °C in an H2 / Ar atmosphere for 1 hour at a heating rate of 2 °C / min. -1 The resulting Ru@ZnO sensitive film.

[0041] Example 2

[0042] This invention provides a design method for a tea tree volatile pheromone gas sensor, comprising the following steps:

[0043] Step A: Dissolve zinc nitrate hexahydrate (1.85 mmol, Zn(NO3)2·6H2O) in 55 mL of deionized water to form solution A; Separately, dissolve 2-methylimidazole (20.5 mmol, MeIM) in 60 mL of deionized water and stir magnetically until the solution becomes clear to obtain solution B.

[0044] Solution A and solution B were mixed to obtain a mixture. 25.75 mL of a 29% ammonia solution was quickly added to the mixture, and then the mixture was magnetically stirred at 1000 rpm for 3 hours at room temperature.

[0045] Step B: After chemical precipitation, transfer the suspension to a 50 mL centrifuge tube. Then, wash the precipitate three times with ethanol by centrifugation to collect a clean precipitate. The centrifuge speed is set to 8000 rpm for 8 minutes. Next, dry the precipitate at 70°C for 27 hours to remove moisture and ethanol from the sample, obtaining a dried sample.

[0046] Step C: Calcine the obtained dried sample at 500℃ for 3 hours (heating rate of 10℃ / min) to finally obtain a cake-shaped ZnO sensitive thin film material.

[0047] Step D: Immerse 0.125 g of the prepared ZnO sensitive film material in 5 mL of deionized water; magnetically stir at 6000-10000 rpm at room temperature; then add 0.0042 g of potassium hexachlororuthenate (III) (K3(RuCl6). The mixture is stirred at room temperature for 24 hours. After stirring, the sample is dried overnight at 70 °C; finally, the dried material is calcined at 300 °C in an H2 / Ar atmosphere for 1 hour at a heating rate of 2 °C / min. -1 The resulting Ru@ZnO sensitive film.

[0048] Example 3

[0049] This invention provides a design method for a tea tree volatile pheromone gas sensor, comprising the following steps:

[0050] Step A: Dissolve zinc nitrate hexahydrate (2.7 mmol, Zn(NO3)2·6H2O) in 55 mL of deionized water to form solution A; Separately, dissolve 2-methylimidazole (30 mmol, MeIM) in 100 mL of deionized water and stir magnetically until the solution becomes clear to obtain solution B.

[0051] Solution A and solution B were mixed to obtain a mixture. 36 mL of a 29% ammonia solution was quickly added to the mixture, and then the mixture was magnetically stirred at 500 rpm for 4 hours at room temperature.

[0052] Step B: After chemical precipitation, transfer the suspension to a 50 mL centrifuge tube. Then, wash the precipitate three times with ethanol by centrifugation to collect a clean precipitate. The centrifuge speed is set to 10,000 rpm for 10 minutes. Next, dry the precipitate at 80°C for 48 hours to remove moisture and ethanol from the sample, obtaining a dried sample.

[0053] Step C: Calcine the obtained dried sample at 700℃ for 4 hours (heating rate of 20℃ / min) to finally obtain a cake-shaped ZnO sensitive thin film material.

[0054] Step D: Immerse 0.2 g of the prepared ZnO sensitive film material in 5 mL of deionized water; magnetically stir at 10,000 rpm at room temperature; then add 0.004 g of potassium hexachlororuthenate (III) (K3(RuCl6). The mixture is stirred at room temperature for 24 hours. After stirring, the sample is dried overnight at 80 °C; finally, the dried material is calcined at 400 °C in an H2 / Ar atmosphere for 1 hour at a heating rate of 2 °C / min. -1 The resulting Ru@ZnO sensitive film.

[0055] Example 4

[0056] The present invention provides an application of a tea tree volatile pheromone gas sensor for detection, comprising the following steps:

[0057] Zinc oxide material is dispersed in a small amount of ethanol, then brushed onto the electrode, air-dried, and then dried in an oven at 60-80℃ for use in gas-sensitive testing.

[0058] Morphological observation and performance testing:

[0059] The Ru@ZnO sensitive thin film sample prepared in Example 3 of this invention was subjected to morphological observation and performance testing, and the following results were obtained:

[0060] By observing SEM analysis (such as...) Figure 1 The prepared gas-sensitive material is a disc-shaped nanostructure; XRD analysis (e.g.) shows that... Figure 2 The prepared material mainly contains Ru@ZnO; through XPS analysis (e.g. Figure 3 The prepared material shows a very obvious peak in the C1s plot;

[0061] In the gas-sensing application of the Ru@ZnO sensitive film described above, the Ru@ZnO sensitive film is dispersed in a small amount of ethanol, then brushed onto the electrode, dried, and then baked in an oven at 60-80°C. After aging on an aging bench for one week, gas-sensing detection is performed. The sensor in this invention performs gas-sensing testing on leaf alcohol at an operating temperature of 225°C.

[0062] Figure 4 This is a concentration gradient test of the prepared Ru@ZnO sensitive film at an operating temperature of 225℃; Figure 5 The selectivity of the prepared Ru@ZnO sensitive film for leaf alcohol, phenethyl alcohol, decanal, linalool, phenethyl alcohol, farnesene, ocimene, geraniol, n-octanol, benzaldehyde and leaf alcohol acetate was tested at a working temperature of 225℃.

[0063] In summary, the nanomaterials of the present invention exhibit outstanding selectivity and excellent gas-sensing properties at 225°C.

[0064] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A design method for a tea tree volatile pheromone gas sensor, characterized in that, Includes the following steps: Step A: Dissolve zinc nitrate hexahydrate in deionized water to form solution A; Dissolve 2-methylimidazole in deionized water to obtain solution B; Mix solutions A and B to obtain a mixture. Quickly add a 29% (w / w) ammonia solution to the mixture and stir for 2-4 hours. Step B: After the chemical precipitation is complete, transfer the suspension to a 50mL centrifuge tube, use ethanol to centrifuge and wash the precipitate, and dry it to obtain the first dry sample. Step C: Calcine the first dried sample to obtain a cake-shaped ZnO sensitive thin film material; Step D: Immerse the ZnO sensitive film material in deionized water; then add potassium hexachlororuthenate, stir, and dry overnight to obtain a second dried sample. Calcine the second dried sample to obtain the Ru@ZnO sensitive film.

2. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, In step A, the molar ratio of zinc nitrate hexahydrate, 2-methylimidazole, and 29% ammonia solution is 1-2.7 mmol: 11-30 mmol: 15.5-36 mL.

3. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, In step B, the centrifugation speed is set to 6000-10000 rpm, and the centrifugation time is 5-10 min.

4. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, In step B, the drying temperature is 60-80℃ and the drying time is 6-48 hours.

5. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, In step C, the calcination temperature is 300-700℃ and the calcination time is 1-4h.

6. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, In step C, the heating rate for calcination is 1-20℃ / min.

7. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, In step D, the calcination conditions are: calcination at 200-400℃ in an atmosphere containing H2 / Ar for 1 hour.

8. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, In step D, the heating rate for calcination is 2°C / min. -1 .

9. The design method of a tea tree volatile pheromone gas sensor according to claim 1, characterized in that, The mass ratio of ZnO sensitive thin film material to potassium hexachlororuthenate is 10-50:

1.

10. A detection application of a tea tree volatile pheromone gas sensor, characterized in that, The gas sensor obtained by the design method according to any one of claims 1-9 above, the detection application of the gas sensor includes the following steps: Zinc oxide material is dispersed in a small amount of ethanol, then brushed onto the electrode, air-dried, and then dried in an oven at 60-80℃. It is then used to detect volatile pheromones from tea trees.

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