Dendrobium flower-ruthenium dioxide sensor for vanillin detection and preparation method thereof
A green synthesis method mediated by Dendrobium flowers was used to prepare ruthenium dioxide nanoparticle electrochemical sensors, which solved the problems of complexity and environmental pollution in existing vanillin detection and achieved high sensitivity and rapid analysis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-21
- Publication Date
- 2026-04-03
AI Technical Summary
Existing methods for vanillin detection are complex to operate, costly, pollute the environment, and lack sufficient sensitivity, making it difficult to meet the needs for rapid detection and on-site analysis.
Using Dendrobium officinale flower extract as a reducing agent and stabilizer, ruthenium dioxide nanoparticle-modified electrodes were prepared by a green synthesis method to construct an electrochemical sensor, which was then detected using differential pulse voltammetry.
It achieves a simple, low-cost, and environmentally friendly high-sensitivity vanillin detection with a linear range of 10 nM to 100 nM and a detection limit of less than 0.002 nM, making it suitable for rapid analysis of complex samples.
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Figure CN121784112A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the fields of electrochemical sensing technology and nanomaterial preparation, specifically to a Dendrobium flower-ruthenium dioxide sensor for vanillin detection and its preparation method. Background Technology
[0002] Vanillin is an important organic aromatic compound widely found in plants such as vanilla beans. Due to its unique aroma and flavor, it is widely used in food, beverages, cosmetics, and pharmaceuticals, such as in ice cream, milk tea, coffee, and pastries. Studies have shown that vanillin possesses certain physiological activities in human health, such as antioxidant, anti-cancer, and anti-tumor effects. However, excessive intake of vanillin may lead to health problems such as liver dysfunction and nausea. Therefore, accurate detection and monitoring of vanillin content is of great significance.
[0003] Currently, vanillin detection mainly relies on analytical techniques such as high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC / MS), ultraviolet-visible spectrophotometry (UV-Vis spectrophotometry), and capillary electrophoresis. Although these methods have high sensitivity and accuracy, they generally suffer from problems such as complex operation, long detection cycle, expensive instruments, cumbersome sample pretreatment, high reagent consumption, and high technical requirements for operators, which limit their application in rapid detection and on-site analysis.
[0004] In recent years, electrochemical sensing technology has become an important research direction for vanillin detection due to its advantages such as simple operation, rapid response, low cost, and high sensitivity. Transition metal oxides are often used as sensitive functional materials in electrochemical sensors to improve their electrochemical performance. Transition metal oxides (TMOs) possess high specific surface area, excellent chemical stability, and redox activity, showing broad application prospects in energy storage, catalysis, and sensing. However, traditional TMO preparation methods typically rely on high temperature and high pressure conditions and toxic chemical reagents, which are not only complex but also pollute the environment, failing to meet the requirements of green and sustainable development.
[0005] Against this backdrop, green synthesis strategies have become an important research direction for the preparation of nanomaterials. Synthesizing metal oxides through natural plant extracts can avoid the use of toxic reducing agents, enabling the preparation of environmentally friendly, low-cost, and renewable materials. Among these, Dendrobium officinale flowers, rich in polysaccharides, flavonoids, proteins, and other bioactive components, possess excellent reducing properties and stability, providing a new pathway for the green synthesis of metal oxide nanomaterials. Summary of the Invention
[0006] To address the aforementioned technical problems in the prior art, this invention provides a method for preparing a Dendrobium flower-ruthenium dioxide sensor for vanillin detection, the method comprising: S1. Prepare Dendrobium officinale flower extract; S2. Using the Dendrobium officinale flower extract as a reducing agent and stabilizer, react with ruthenium salt solution, and after calcination, obtain ruthenium dioxide nanoparticles synthesized in a green manner mediated by Dendrobium officinale flowers; S3. Modify the ruthenium dioxide nanoparticles onto the surface of the working electrode to obtain the electrochemical sensor.
[0007] In step S1, the Dendrobium officinale flower extract is prepared by the following method: using an ethanol aqueous solution as the extraction solvent, Dendrobium officinale flowers are subjected to ultrasonic-assisted extraction at an extraction temperature of 30-50℃ for 50-70 minutes, followed by filtration and concentration.
[0008] Step S2 includes: S2.1. Mixing the Dendrobium officinale flower extract with a RuCl3·H2O solution with a concentration of 0.001 mol / L, and stirring at 70-90℃ for 1-3 hours to form a mixed product; S2.2. Centrifuging, washing, and drying the mixed product to obtain a precursor powder; S2.3. Calcining the precursor powder at 500-700℃ in an oxygen atmosphere for 2-4 hours to obtain the ruthenium dioxide nanoparticles.
[0009] In a second aspect, the present invention provides an electrochemical sensor prepared by any one of the methods described in the first aspect. The sensor includes a working electrode and a sensitive membrane modified on the surface of the working electrode, the sensitive membrane comprising ruthenium dioxide nanoparticles synthesized in a green manner mediated by Dendrobium officinale flowers.
[0010] Thirdly, the present invention provides an electrochemical detection method for vanillin, wherein the method uses the electrochemical sensor described in the second aspect and employs differential pulse voltammetry to quantitatively detect vanillin in a sample.
[0011] Preferably, the detection parameters of the differential pulse voltammetry include: a potential range of -0.2 V to +1.0 V, a potential increase of 40-60 mV, and a pulse period of 15-25 ms; the detection substrate is a 0.1 M phosphate buffer solution with pH=7.0.
[0012] Preferably, the linear detection range of vanillin is 10 nM to 100 nM, and the detection limit is not higher than 0.002 nM.
[0013] Fourthly, the present invention provides the application of ruthenium dioxide nanoparticles prepared by the above method in the preparation of an electrochemical sensor for detecting vanillin.
[0014] Fifthly, the present invention provides a kit comprising: the electrochemical sensor described in the second aspect; and / or ruthenium dioxide nanoparticles prepared by any one of the methods described in the first aspect.
[0015] The present invention has the following advantages over the prior art: This invention is the first to propose using Dendrobium officinale flower extract as a bio-reducing agent and stabilizer to achieve the green synthesis of ruthenium dioxide nanoparticles. This method completely eliminates the need for toxic reagents and complex processes required in traditional chemical synthesis, such as chlorine and hydrofluoric acid, thus fundamentally solving the environmental pollution and potential biotoxicity problems associated with traditional methods. It exhibits excellent biocompatibility and fully aligns with the development concept of green chemistry.
[0016] Ruthenium dioxide nanoparticles synthesized via Dendrobium flower mediated synthesis, due to their unique morphology and abundant surface functional groups, can provide a large number of active sites for the electrocatalytic oxidation of vanillin molecules after electrode modification, and significantly accelerate electron transport. This enables the constructed electrochemical sensor to exhibit extremely high sensitivity to vanillin, achieving a wide linear range of 10 nM to 100 nM and an extremely low detection limit of no more than 0.002 nM, outperforming most reported sensing methods.
[0017] On the other hand, this invention produces an unexpected synergistic effect. The bioactive components in Dendrobium flower extract not only regulate the growth of nanoparticles during synthesis, but their residual functional groups also produce a synergistic catalytic effect with ruthenium dioxide nanoparticles. This "1+1>2" synergistic effect is the intrinsic key to achieving high-performance detection, which is unmatched by simple physical mixing or traditional chemical synthesis materials.
[0018] The sensor and detection method provided by this invention have advantages such as simple operation, rapid analysis, low cost, and good reproducibility. In the detection of complex real-world samples such as coffee beverages, the recovery rate remained stable between 81.5% and 105.0%, with satisfactory results. This fully demonstrates its strong anti-interference ability in complex matrices and reliable detection results, providing a highly promising and practical tool for rapid on-site monitoring of food quality and safety. This invention applies the specific natural resource of Dendrobium officinale flowers to the green synthesis of functional nanomaterials and the construction of high-sensitivity sensing interfaces, innovating a new application of natural plant resources in nano-electrochemical sensing. It provides a novel material platform and technical approach for the future development of a series of new, high-performance green electrochemical sensors. Attached Figure Description
[0019] Figure 1 It is a standard curve showing the relationship between DPV peak current and vanillin concentration.
[0020] Figure 2 These are the oxidation peak current and DPV measurement curves of different concentrations of vanillin (10nM-200nM). Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention.
[0022] This invention provides a method for preparing a Dendrobium officinale flower-ruthenium dioxide sensor for vanillin detection, characterized by the following steps: S1. Preparing Dendrobium officinale flower extract; S2. Using the Dendrobium officinale flower extract as a reducing agent and stabilizer, reacting it with a ruthenium salt solution, and after calcination, obtaining ruthenium dioxide nanoparticles synthesized in a green manner mediated by Dendrobium officinale flowers; S3. Modifying the ruthenium dioxide nanoparticles onto the surface of a working electrode to obtain the electrochemical sensor.
[0023] In step S1, the Dendrobium officinale flower extract is prepared by the following method: using an ethanol aqueous solution as the extraction solvent, Dendrobium officinale flowers are extracted with ultrasound assistance at an extraction temperature of 30-50℃ for 50-70 minutes, followed by filtration and concentration. Step S2 includes: S2.1. Mixing the Dendrobium officinale flower extract with a 0.1 mol / L RuCl3·H2O solution and stirring at 70-90℃ for 1-3 hours to form a mixed product; S2.2. Centrifuging, washing, and drying the mixed product to obtain a precursor powder; S2.3. Calcining the precursor powder at 500-700℃ in an oxygen atmosphere for 2-4 hours to obtain the ruthenium dioxide nanoparticles.
[0024] This invention provides an electrochemical sensor prepared by a method for detecting vanillin using a Dendrobium flower-ruthenium dioxide sensor. The sensor includes a working electrode and a sensitive membrane modified on the surface of the working electrode. The sensitive membrane contains ruthenium dioxide nanoparticles synthesized in a green manner mediated by Dendrobium flowers. The electrochemical sensor uses differential pulse voltammetry to quantitatively detect vanillin in a sample. The detection parameters of the differential pulse voltammetry include: a potential range of -0.2 V to +1.0 V, a potential amplification of 40-60 mV, and a pulse period of 15-25 ms; the detection solution is a 0.1 M phosphate buffer solution with a pH of 7.0. The detection linear range for vanillin is 10 nM to 100 nM, and the detection limit is not higher than 0.002 nM.
[0025] The application of ruthenium dioxide nanoparticles prepared by the described method in the preparation of an electrochemical sensor for detecting vanillin. The electrochemical sensor utilizes ruthenium dioxide nanoparticles prepared by the described method. The kit is used for the detection of vanillin content in food products, including coffee beverages and / or bread.
[0026] This invention utilizes RuO2 mediated by Dendrobium officinale flowers to construct an electrochemical sensor. First, Dendrobium officinale flowers are crudely extracted using ethanol as a solvent via ultrasonic-assisted extraction. This crude extract is then used as a reducing stabilizer for RuCl3·H2O to synthesize RuO2. Next, using a glassy carbon electrode (GCE) as the working electrode, 10 μL of 1 mg / mL RuO2 is applied to the working electrode via a drop-coating method (RuO2 / GCE). Differential pulse voltammetry (DPV) is used to detect vanillin within a potential range of -0.2 V to +1.2 V. The bioactive components in the Dendrobium officinale flower extract act as reducing and stabilizing agents to regulate the growth of RuO2 nanoparticles, providing abundant active sites for vanillin molecules and accelerating electron transport at the electrode interface, thus enabling quantitative detection of vanillin.
[0027] Example 1
[0028] This invention relates to a green synthesis of transition metal RuO2 nanoparticles mediated by Dendrobium officinale flowers and an electrochemical method for vanillin detection. First, Dendrobium officinale flowers are crudely extracted using ethanol via ultrasound-assisted extraction. This crude extract is then used as a reducing stabilizer for RuCl3·H2O to synthesize RuO2. Second, using a gas collector electrode (GCE) as the working electrode, 1 mg / mL RuO2 is modified onto the electrode via a drop-coating method (RuO2 / GCE). Vanillin is then detected using differential pulse voltammetry (DPV) at a potential of -0.2 V.
[0029] Crude Extraction of Dendrobium officinale Flowers: Select fresh Dendrobium officinale flowers and wash them with distilled water. Place 5 g of the processed Dendrobium officinale flowers in a beaker, add 30 mL of extraction solvent (75% ethanol), mix, and then place in an ultrasonic device for extraction. The vibration of ultrasound can accelerate the dissolution of components and shorten the extraction time. Parameters such as ultrasonic power, extraction time, and temperature will affect the extraction effect. Generally, the ultrasonic power should be used according to the laboratory ultrasonic settings, the extraction time should be 60 minutes, and the temperature should be controlled at around 40℃. After extraction, separate the extract from the residue through three filtrations to obtain a clear extract. Use a rotary evaporation method at room temperature for 30 minutes to remove the ethanol solvent, obtaining a concentrated solution. Wrap it in aluminum foil and store it in the upper part of a 4℃ refrigerator for use within 7 days.
[0030] Preparation of RuO2. 10 mL of crude Dendrobium flower extract was added to 50 mL of 0.1 mol / L RuCl3·H2O in a 250 mL Erlenmeyer flask and stirred at 80 °C for two hours at 100 rpm. After thorough stirring, particles were formed and collected by centrifugation at 8000 rpm for 25 min. The centrifuged particles were washed with deionized water and centrifuged again at 8000 rpm for 15 min. The centrifuged sample was dried in an oven at 60 °C for 2 h and then ground into powder using a mortar and pestle. This powder sample was calcined in a tube furnace at 600 °C under a nitrogen atmosphere for 3 h to obtain ruthenium oxide nanoparticles, which were then ground into smaller particles and placed in vials for characterization and electrochemical studies.
[0031] Preparation of the electrochemical sensor. First, glassy carbon electrodes (working electrodes) were polished using Al2O3 powders of different particle sizes (0.05 μm and 0.3 μm), and then rinsed for 1 min each in ultrapure water, anhydrous ethanol, and ultrapure water. After drying with a blower, they were ready for use. Second, RuO2 material (99.26 nm particle size) was drop-coated: RuO2 material (10 μL and 1 mg / mL concentration) was drop-coated onto the prepared electrode surface. This electrode was designated as the RuO2 / GCE electrode. After air-drying at room temperature, it was ready for use and detection.
[0032] Vanillin content determination. An electrochemical workstation was used with a three-electrode system: a saturated calomel electrode as the reference electrode, a platinum wire electrode as the counter electrode, and a glassy carbon electrode as the working electrode. Differential pulse voltammetry (DPV) was employed in 0.1 M PBS electrolyte containing different concentrations of vanillin (pH=7.0), and the scan curves were recorded. (DPV parameter settings: potential amplification: 50 mV, potential range: from -0.2 V to 1.0 V, pulse period: 20 ms). The standard curve showing the relationship between DPV peak current and vanillin concentration is shown below. Figure 1 As shown, the current magnitude and vanillin exhibit a good linear relationship within the linear range of 10 nM to 100 nM, with a correlation coefficient R0. 2 The value is 0.93437, and the linear equation is I. pa (µA) = 36.49176logC Vanillin -15.88758, detection limit is 0.001540 nM. Compared with other sensors, the sensor proposed in this invention has a wider linear range and a lower detection limit. It is the first to use Dendrobium officinale flowers as a reducing stabilizer for RuO2 nanoparticles. The biomolecule content in Dendrobium officinale flowers determines the morphology and structure of RuO2 nanoparticles, thus providing abundant active sites for the electrocatalytic oxidation of vanillin, achieving quantitative detection of vanillin.
[0033] Determination of vanillin content in actual samples. First, 60 mL of coffee sample was sonicated for 30 minutes to obtain a homogeneous suspension. The suspension was then centrifuged at 1500 r / min for 15 min to obtain the supernatant, i.e., the coffee sample solution. Three equal volumes (e.g., 10 mL) of the coffee sample solution were taken, and 40 nM, 60 nM, and 80 nM vanillin standard working solutions were added respectively. After mixing, three groups of spiked samples were obtained. Using RuO2 / GCE as the working electrode, the current response signal was measured by the DPV method. The recovery rate of vanillin in the samples was calculated to be between 81.5% and 105.0% according to the standard curve (see Table 1). This indicates that the RuO2 nanoparticle sensor synthesized through Dendrobium flower-mediated synthesis has the potential for rapid and accurate detection of vanillin in complex actual samples, providing a new approach for the development of green sensing materials and food quality control.
[0034] Table 1:
[0035] Coffee samples Concentration of added vanillin (nM) Actual measured concentration of vanillin (nM) Recovery rate (%) RSD (%) 1 0 0 0 0 2 40 32.62 81.5 1.06925 3 60 57.95 96.6 1.05357 4 80 70.96 105.0 1.13248
[0036] The present invention provides a kit comprising: the electrochemical sensor described in the second aspect; and / or ruthenium dioxide nanoparticles prepared by any one of the methods described in the first aspect.
[0037] The signal amplification technique in the above system utilizes RuO2 to provide active sites for vanillin, enabling electrocatalytic oxidation to achieve signal amplification. In this invention, RuO2 nanoparticles are loaded onto the electrode substrate surface, forming a three-phase interface of "electrode-RuO2 nanoparticles-electrolyte". Vanillin molecules are dispersed in the electrolyte, and the active sites (containing...) are exposed on the surface of the RuO2 nanoparticles. (Electrode pair and -OH group). Vanillin molecules form hydrogen bonds with the -OH groups on the RuO2 surface through phenolic hydroxyl groups, or rapidly adsorb onto the active sites of RuO2 nanoparticles through π-π stacking, thus completing "molecular anchoring". Under the action of an external electric field, the RuO2 surface Ru... 4+ Acquire electrons and convert them into The adsorbed vanillin molecule undergoes oxidation, losing one electron to transform into a quinone structure (vanillin quinone). Finally, a stable current-potential signal is captured by the DPV method to achieve quantitative concentration detection.
[0038] Example 2
[0039] In step S1, the extraction temperature is 50℃ and the extraction time is 50 minutes, followed by filtration and concentration. Step S2 includes: S2.1. Mixing the Dendrobium officinale flower extract with a 0.001 mol / L RuCl3·H2O solution and stirring at 70℃ for 3 hours to form a mixed product; S2.2. Centrifuging, washing, and drying the mixed product to obtain precursor powder; S2.3. Calcining the precursor powder at 700℃ for 2 hours under an inert atmosphere to obtain ruthenium dioxide nanoparticles. Other steps are the same as in Example 1.
[0040] Example 3
[0041] In step S1, the Dendrobium officinale flower extract is prepared by the following method: using an ethanol aqueous solution as the extraction solvent, Dendrobium officinale flowers are extracted with ultrasound assistance at an extraction temperature of 30°C for 70 minutes, followed by filtration and concentration. Step S2 includes: S2.1. Mixing the Dendrobium officinale flower extract with a 0.001 mol / L RuCl3·H2O solution and stirring at 90°C for 1 hour to form a mixed product; S2.2. Centrifuging, washing, and drying the mixed product to obtain a precursor powder; S2.3. Calcining the precursor powder at 500°C for 2 hours under an oxygen atmosphere to obtain the ruthenium dioxide nanoparticles.
[0042] This invention provides a method for the green synthesis of ruthenium dioxide nanoparticles based on Dendrobium officinale flower extract and their application in constructing a highly sensitive vanillin electrochemical sensor. This technology, for the first time, utilizes Dendrobium officinale flower extract as a bioreducing agent and stabilizer, preparing ruthenium dioxide nanoparticles via an environmentally friendly synthetic route, completely avoiding the use of toxic reagents in traditional methods, thus conforming to the principles of green chemistry. The resulting sensor exhibits excellent performance in vanillin detection, with a linear detection range of 10-100 nM and a detection limit as low as 0.002 nM, achieving satisfactory recoveries of 81.5%-105.0% in complex real-world samples such as coffee. The synergistic effect between the bioactive components in Dendrobium officinale flowers and the ruthenium dioxide nanoparticles provides abundant electrocatalytic active sites for vanillin molecules, significantly enhancing electron transport efficiency. This method offers advantages such as simple operation, low cost, and rapid detection, providing a reliable solution for the rapid on-site detection of vanillin in food, and has broad application prospects in the field of food safety monitoring.
[0043] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings and specific examples. However, the present invention is not limited to the above embodiments. Several modifications and improvements can be made without departing from the concept of the present invention. All changes, modifications, substitutions, combinations, and simplifications made based on the spirit and principle of the technical solution of the present invention should be considered equivalent substitutions. As long as they meet the purpose of the present invention and do not deviate from the technical principles and inventive concept of the preparation method, electrochemical measurement method and application of vanillin electrochemical sensor based on Dendrobium flower-mediated synthesis of transition metal ruthenium oxide nanoparticles, they all fall within the protection scope of the present invention.
Claims
1. A method for preparing a Dendrobium flower-ruthenium dioxide sensor for vanillin detection, characterized in that, Includes the following steps: S1. Preparation of Dendrobium officinale flower extract; S2. Using the Dendrobium officinale flower extract as a reducing agent and stabilizer, reacting it with a ruthenium salt solution, and after calcination, obtaining ruthenium dioxide nanoparticles synthesized in a green manner mediated by Dendrobium officinale flowers; S3. The ruthenium dioxide nanoparticles are modified onto the surface of the working electrode to obtain the electrochemical sensor.
2. The method for preparing a Dendrobium flower-ruthenium dioxide sensor for vanillin detection according to claim 1, characterized in that, In step S1, the Dendrobium officinale flower extract is prepared by the following method: using an ethanol aqueous solution as the extraction solvent, Dendrobium officinale flowers are subjected to ultrasonic-assisted extraction at an extraction temperature of 30-50℃ for 50-70 minutes, followed by filtration and concentration.
3. The method for preparing a Dendrobium flower-ruthenium dioxide sensor for vanillin detection according to claim 1 or 2, characterized in that, Step S2 includes: S2.
1. Mix the Dendrobium officinale flower extract with a RuCl3·H2O solution with a concentration of 0.001 mol / L, and stir at 70-90℃ for 1-3 hours to form a mixed product; S2.
2. The mixture is centrifuged, washed, and dried to obtain precursor powder; S2.
3. The precursor powder is calcined at 500-700°C in an oxygen atmosphere for 2-4 hours to obtain the ruthenium dioxide nanoparticles.
4. An electrochemical sensor prepared by the method for preparing a Dendrobium flower-ruthenium dioxide sensor for vanillin detection according to any one of claims 1-3, characterized in that, The sensor includes a working electrode and a sensitive membrane modified on the surface of the working electrode, the sensitive membrane containing ruthenium dioxide nanoparticles synthesized in a green manner mediated by Dendrobium flowers.
5. An electrochemical detection method for vanillin, characterized in that, Using the electrochemical sensor as described in claim 4, the vanillin in the sample was quantitatively detected by differential pulse voltammetry.
6. The electrochemical detection method for vanillin according to claim 5, characterized in that, The detection parameters of the differential pulse voltammetry include: a potential range of -0.2 V to +1.0 V, a potential increase of 40-60 mV, and a pulse period of 15-25 ms; the detection solution is 0.1 M phosphate buffer solution with a pH of 7.
0.
7. The electrochemical detection method for vanillin according to claim 5 or 6, characterized in that, The detection linear range of vanillin is 10 nM to 100 nM, and the detection limit is not higher than 0.002 nM.
8. The use of ruthenium dioxide nanoparticles prepared by the method of any one of claims 1-3 in the preparation of an electrochemical sensor for detecting vanillin.
9. A reagent kit, characterized in that, The kit comprises: the electrochemical sensor as described in claim 4 and / or ruthenium dioxide nanoparticles prepared by the method of any one of claims 1-3.
10. The reagent kit according to claim 9, characterized in that, The kit is used to detect vanillin content in food, including coffee beverages.