A core-shell zeolitic imidazolate framework derivative material modified electrode and a preparation method and application thereof
By preparing electrodes modified with core-shell zeolite imidazole framework-derived materials, the complexity and high cost of quantitative detection of scutellarin were solved, enabling simple and efficient BVC detection, which is suitable for wireless portable sensors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HAINAN NORMAL UNIV
- Filing Date
- 2023-08-24
- Publication Date
- 2026-04-21
AI Technical Summary
Existing quantitative detection methods for scutellarin (BVC) have limitations such as long analysis time, expensive instruments, complex operation, and high consumption of organic solvents. There is a need to develop a simpler and more efficient detection method.
The electrode was modified with a core-shell zeolite imidazole framework-derived material. The core-shell zeolite imidazole framework material (ZIF-67@ZIF-8) was prepared and pyrolyzed to obtain a nitrogen-doped carbon nanotube polyhedron material (Co/C-NCNP) derived from the core-shell zeolite imidazole framework. This material was then modified onto the electrode surface and detected by differential pulse voltammetry.
It achieves sensitive detection of BVC in the concentration range of 0.15 to 100.0 μM, with a detection limit as low as 0.014 μM. The sensor is simple to prepare, highly sensitive, and portable, making it suitable for wireless portable sensors and exhibiting good detection performance.
Smart Images
Figure CN117074486B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wireless portable electrochemical sensor technology, and particularly relates to a core-shell zeolite imidazole framework-derived electrode, its preparation method and application. Background Technology
[0002] Breviscapine (BVC) is a flavonoid compound extracted from the traditional Chinese medicine *Erigeron breviscapus*. It possesses various pharmacological activities, including promoting blood circulation, clearing meridians, dilating blood vessels, inhibiting platelet aggregation, reducing myocardial ischemia-reperfusion injury, reducing oxidative damage, and alleviating non-alcoholic steatohepatitis. Therefore, BVC has been widely used in the treatment of coronary heart disease such as angina pectoris, myocardial ischemia, cerebral ischemia, and cerebral thrombosis. Currently, there are some reports on the quantitative detection of BVC, including enzymatic methods and methods such as liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS / MS), chemiluminescence, proton nuclear magnetic resonance spectroscopy (PCNMR), LC-MS / MS, and ultra-high performance liquid chromatography-MS / MS. However, these methods all have certain limitations, such as long analysis time, expensive instruments, complex operation, and high consumption of organic solvents. Therefore, it is necessary to provide a new quantitative detection method for BVC. Summary of the Invention
[0003] To address the aforementioned technical problems, this invention proposes a core-shell zeolite imidazole framework-derived electrode, its preparation method, and its application.
[0004] To achieve the above objectives, the present invention provides a method for preparing an electrode modified with a core-shell zeolite imidazole framework-derived material, comprising the following steps:
[0005] Cobalt-based zeolite imidazole framework materials were synthesized using cobalt nitrate hexahydrate and 2-methylimidazole as precursors. Zinc nitrate hexahydrate was then added, and core-shell zeolite imidazole framework materials (ZIF-67@ZIF-8) were synthesized by epitaxial growth.
[0006] The core-shell zeolite imidazole framework material was pyrolyzed to obtain nitrogen-doped carbon nanotube polyhedral material (Co / C-NCNP) derived from the core-shell zeolite imidazole framework.
[0007] The nitrogen-doped carbon nanotube polyhedral material derived from the core-shell zeolite imidazole framework was added to water to obtain a suspension. The suspension was then drop-coated onto the surface of the working electrode to obtain a core-shell zeolite imidazole framework-derived material modified electrode (Co / C-NCNP / SPCE).
[0008] Furthermore, the method for synthesizing the core-shell zeolite imidazole framework material by epitaxial growth is as follows:
[0009] Cobalt nitrate hexahydrate, 2-methylimidazole and zinc nitrate hexahydrate were dissolved in methanol and sonicated to obtain cobalt nitrate hexahydrate solution, 2-methylimidazole solution and zinc nitrate hexahydrate solution respectively.
[0010] The cobalt nitrate hexahydrate solution was added to the 2-methylimidazole solution and stirred until homogeneous. Then, the zinc nitrate hexahydrate solution was added and stirred until homogeneous. The mixture was aged, the precipitate was washed, centrifuged, and dried to obtain the core-shell zeolite imidazole framework material.
[0011] Furthermore, the mass ratio of cobalt nitrate hexahydrate, zinc nitrate hexahydrate, and 2-methylimidazole is (4-4.5):(4-4.5):(4.5-5), preferably 4.376:4.472:4.988.
[0012] Furthermore, the ultrasound time is 10 minutes; the aging time is 12 hours; the centrifugation speed is 8000 rpm; and the drying temperature is 85°C for 5 hours.
[0013] Furthermore, the method for synthesizing core-shell ZIF-67@ZIF-8 via epitaxial growth is as follows:
[0014] 4.376 g Co(NO3)2·6H2O, 4.472 g Zn(NO3)2·6H2O, and 4.988 g 2-methylimidazole were dissolved in 60 mL methanol, 60 mL methanol, and 120 mL methanol, respectively. The solutions were sonicated at room temperature for 10 min to obtain homogeneous Co(NO3)2·6H2O, Zn(NO3)2·6H2O, and 2-methylimidazole solutions. The Co(NO3)2·6H2O solution was added to the 2-methylimidazole solution, and the mixture was stirred for 10 min. Then, the Zn(NO3)2·6H2O solution was added to the above solutions, and the mixture was stirred for another 1 h. The resulting suspension was allowed to stand for 12 h, and the precipitate was centrifuged three times with methanol at 8000 rpm. The precipitate was then dried at 85 °C for 5 h to obtain core-shell ZIF-67@ZIF-8.
[0015] Furthermore, the pyrolysis is carried out in an argon atmosphere; the pyrolysis temperature is 920℃, the time is 4h, and the heating rate is 5℃ / min.
[0016] Furthermore, the water used to prepare the suspension is ultrapure water, and the concentration of the suspension is 2.0 mg / mL.
[0017] An electrode modified with a core-shell zeolite imidazole framework-derived material was prepared according to the above preparation method.
[0018] A wireless portable sensor uses an electrode modified with the core-shell zeolite imidazole framework-derived material as a sensing element.
[0019] Furthermore, by using the core-shell zeolite imidazole framework-derived material to modify the electrode as a sensing element, it can be connected to a handheld electrochemical workstation to serve as a wireless portable sensor.
[0020] The application of the wireless portable sensor in detecting scutellarin (BVC).
[0021] A method for applying the aforementioned wireless portable sensor involves placing the wireless portable sensor in a analyte containing scutellarin and detecting the electrochemical signal of scutellarin in the analyte using differential pulse voltammetry at a potential of -0.2 to 0.5 V.
[0022] Furthermore, when detecting BVC, the concentration of BVC in the analyte solution ranged from 0.15 to 100.0 μM, and the buffer solution was 0.1 M phosphate-buffered saline (PBS, pH 5.0); differential pulse voltammetry (DPV) was used with a potential of -0.2 to 0.5 V and an enrichment time of 688.1 s. The wireless portable sensor had a detection range of 0.15 to 100.0 μM for BVC and a detection limit of 0.014 μM.
[0023] Compared with the prior art, the present invention has the following advantages and technical effects: Co / C-NCNP material has a good catalytic effect on BVC, providing high electron transport efficiency and large specific surface area for the redox process, increasing the adsorption amount of BVC on the Co / C-NCNP / SPCE surface and the electrochemical redox rate.
[0024] The Co / C-NCNP-based sensor developed in this invention is simple to prepare, highly sensitive, portable, and inexpensive. It can sensitively detect BVC in the concentration range of 0.15–100.0 μM, with a detection limit as low as 0.014 μM. The sensor was applied to actual samples of *Ligustrum lucidum* pollen and demonstrated good detection performance. Attached Figure Description
[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:
[0026] Figure 1 This is a schematic diagram of the preparation process of Co / C-NCNP and the sensing strategy for BVC in Example 1.
[0027] Figure 2The images shown are: (A, B) Scanning electron microscope (SEM) images of the core-shell ZIF-67@ZIF-8 in Example 1; (C, D) Elemental mapping of Co and Zn in the core-shell ZIF-67@ZIF-8; (E, F) SEM images of Co / C-NCNP; and (G, H) Transmission electron microscope (TEM) images of Co / C-NCNP.
[0028] Figure 3 The XRD patterns of (A) Co / C-NCNP, synthesized core-shell ZIF-67@ZIF-8, simulated ZIF-67, simulated ZIF-8 and Co in Example 1; (B) Infrared spectra of Co / C-NCNP and core-shell ZIF-67@ZIF-8; (C) Nitrogen adsorption / desorption isotherm of Co / C-NCNP; (D) Pore size distribution curve of Co / C-NCNP.
[0029] Figure 4 The CV behavior of 50 μM BVC in 0.1 M PBS (pH 5.0) on (a) bare SPCE and (b) ZIF-67@ZIF-8 / SPCE; (B) CV behavior of 50 μM BVC in 0.1 M PBS (pH 5.0) on (c) ZIF-8-920 / SPCE and (d) ZIF-67-920 / SPCE; (C) CV behavior in 0.1 M PBS (pH 5.0) on (e) without BVC and (f) with 50 μM BVC, enrichment time: 688.1 s, scan rate: 100 mV / s.
[0030] Figure 5 The image shows the CV curves of (A) Co / C-NCNP / SPCE in PBS containing 50 μM BVC at different pH values (3.0, 4.0, 5.0, 6.0, 7.0) in Example 1; and (B) the effect on oxidation peak potential and oxidation peak current.
[0031] Figure 6 The image shows the CV curves of Co / C-NCNP / SPCE (A) in 0.1M PBS containing 50μM BVC at different scan rates: 20, 50, 75, 100, 120, 150, 200, 250, 300, 350, 400, and 600 mV / s. (B) I pa I pc With υ 1 / 2 The linear relationship.
[0032] Figure 7The following are examples from Example 1: (A) DPV curves of different concentrations of BVC (al: 0, 0.15, 0.2, 0.5, 1.0, 5.0, 10.0, 15.0, 20.0, 50.0, 80.0, 100.0 μM) on Co / C-NCNP / SPCE; (B) Relationship between oxidation peak current and BVC concentration.
[0033] Figure 8 In Example 1, (A) the DPV response of 50.0 μM BVC containing different interfering substances on Co / C-NCNP / SPCE; (B) the DPV response of 8 independent electrodes prepared under the same conditions to 50.0 μM BVC; (C) the CV response of 50 μM BVC after 100 cycles on Co / C-NCNP / SPCE; and (D) the CV plot after 100 cycles after storage for 30 days. Detailed Implementation
[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0035] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0036] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0037] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0038] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0039] In this embodiment of the invention, room temperature refers to 25±3℃.
[0040] The commercially available screen-printed electrode (SPCE) in this embodiment of the invention was purchased from Qingdao Botan Technology Co., Ltd.
[0041] Example 1
[0042] (1) Preparation of ZIF-67@ZIF-8: 4.376 g Co(NO3)2·6H2O, 4.472 g Zn(NO3)2·6H2O, and 4.988 g 2-methylimidazole were dissolved in 60 mL methanol, 60 mL methanol, and 120 mL methanol, respectively. The solutions were sonicated at room temperature for 10 min to obtain homogeneous Co(NO3)2·6H2O, Zn(NO3)2·6H2O, and 2-methylimidazole solutions. The Co(NO3)2·6H2O solution was poured into the 2-methylimidazole solution and stirred for 10 min. Then, the Zn(NO3)2·6H2O solution was poured into the above solutions, and stirring was continued for 1 h. The resulting suspension was allowed to stand for 12 h. The precipitate was washed with methanol and centrifuged three times at 8000 rpm. Then, it was dried at 85 °C for 5 h to obtain core-shell ZIF-67@ZIF-8.
[0043] (2) Preparation of Co / C-NCNP: The core-shell ZIF-67@ZIF-8 prepared in (1) was placed in a tube furnace and pyrolyzed at 920℃ under an argon atmosphere. The heating rate was 5℃ / min and the pyrolysis lasted for 4h to prepare Co / C-NCNP.
[0044] (3) Preparation of Co / C-NCNP / SPCE: The Co / C-NCNP prepared in (2) was dispersed in ultrapure water to obtain a Co / C-NCNP suspension with a concentration of 2.0 mg / mL. 20 μL of the Co / C-NCNP suspension was drop-coated onto the working electrode surface of the SPCE and air-dried at room temperature to obtain a modified electrode (Co / C-NCNP / SPCE) based on nitrogen-doped carbon nanotube polyhedral material derived from a core-shell zeolite imidazole framework. The preparation process of Co / C-NCNP and the schematic diagram of the sensing strategy for BVC in this embodiment are shown in the figure. Figure 1 .
[0045] Comparative Example 1
[0046] Same as Example 1, except that the core-shell ZIF-67@ZIF-8 was pyrolyzed in an argon atmosphere at 900°C for 4 hours at a heating rate of 5°C / min. Too low a pyrolysis temperature is detrimental to the Zn... 2+Evaporation reduces the catalytic effect on BVC, leading to a decrease in the rate of electrochemical redox reaction.
[0047] Comparative Example 2
[0048] Similar to Example 1, except that the core-shell ZIF-67@ZIF-8 was pyrolyzed in an argon atmosphere at a temperature of 950°C for 4 hours at a heating rate of 5°C / min. Excessive pyrolysis temperature reduced the material's specific surface area, decreasing the contact area for the BVC redox reaction and consequently lowering the electrochemical redox reaction rate.
[0049] Comparative Example 3
[0050] (1) Preparation of ZIF-67: 4.376 g Co(NO3)2·6H2O and 4.988 g 2-methylimidazole were dissolved in 60 mL methanol and 120 mL methanol, respectively, and sonicated at room temperature for 10 min to obtain homogeneous Co(NO3)2·6H2O solution and 2-methylimidazole solution. The Co(NO3)2·6H2O solution was poured into the 2-methylimidazole solution and stirred for 1 h. The resulting suspension was allowed to stand and age for 12 h. The precipitate was washed with methanol, centrifuged three times at 8000 rpm, and then dried at 85 °C for 5 h to obtain core-shell ZIF-67.
[0051] (2) Preparation of ZIF-67-920: The core-shell ZIF-67 prepared in (1) was placed in a tube furnace and pyrolyzed at 920℃ under an argon atmosphere. The heating rate was 5℃ / min and the pyrolysis lasted for 4h to obtain ZIF-67-920.
[0052] Preparation of ZIF-67-920 / SPCE: 20 μL of 2.0 mg / mL ZIF-67-920 suspension was drop-coated onto the working electrode surface of SPCE and dried at room temperature to obtain ZIF-67-920 / SPCE.
[0053] Comparative Example 4
[0054] (1) Preparation of ZIF-8: 4.472 g Zn(NO3)2·6H2O and 4.988 g 2-methylimidazole were dissolved in 60 mL methanol and 120 mL methanol, respectively, and sonicated at room temperature for 10 min to obtain homogeneous Zn(NO3)2·6H2O solution and 2-methylimidazole solution. The Zn(NO3)2·6H2O solution was poured into the 2-methylimidazole solution and stirred for 1 h. The resulting suspension was allowed to stand for 12 h. The precipitate was washed with methanol, centrifuged three times at 8000 rpm, and then dried at 85 °C for 5 h to obtain core-shell ZIF-8.
[0055] (2) Preparation of ZIF-8-920: The core-shell ZIF-8 prepared in (1) was placed in a tube furnace and pyrolyzed at 920℃ under an argon atmosphere. The heating rate was 5℃ / min and the pyrolysis was carried out for 4h to obtain ZIF-8-920.
[0056] Preparation of ZIF-8-920 / SPCE: 20 μL of 2.0 mg / mL ZIF-8-920 suspension was drop-coated onto the working electrode surface of SPCE and dried at room temperature to obtain ZIF-8-920 / SPCE.
[0057] Comparative Example 5
[0058] Preparation of ZIF-67@ZIF-8 / SPCE: 20 μL of 2.0 mg / mL ZIF-67@ZIF-8 suspension was drop-coated onto the working electrode surface of SPCE and air-dried at room temperature to obtain ZIF-67@ZIF-8 / SPCE.
[0059] Comparative Example 6
[0060] bare SPCE: Screen-printed electrode SPCE.
[0061] in:
[0062] The ZIF-67-920 suspension was prepared by dispersing ZIF-67-920 in ultrapure water to obtain a ZIF-67-920 suspension with a concentration of 2.0 mg / mL.
[0063] The ZIF-8-920 suspension was prepared by dispersing ZIF-8-920 in ultrapure water to obtain a ZIF-8-920 suspension with a concentration of 2.0 mg / mL.
[0064] The ZIF-67@ZIF-8 suspension was prepared by dispersing ZIF-67@ZIF-8 in ultrapure water to obtain a ZIF-67@ZIF-8 suspension with a concentration of 2.0 mg / mL.
[0065] The Co / C-NCNP / SPCE prepared in Example 1 was used as the sensitive element of the electrochemical sensor. When connected to a handheld electrochemical workstation, it can be used as a wireless portable electrochemical sensor for BVC detection.
[0066] Test Example 1
[0067] The structure and morphology of the material prepared in Example 1 were characterized.
[0068] Figure 2The images shown are (A, B) scanning electron microscope (SEM) images of the core-shell ZIF-67@ZIF-8 in Example 1, showing that the core-shell ZIF-67@ZIF-8 is a rhombic dodecahedral crystal; (C, D) are mapping images of elements Co and Zn in the core-shell ZIF-67@ZIF-8, confirming that a core-shell structure material with ZIF-67 as the core and ZIF-8 as the shell was obtained by epitaxial growth; (E, F) are SEM images of Co / C-NCNP, showing that the core-shell ZIF-67@ZIF-8 was pyrolyzed at high temperature in an inert atmosphere to obtain a nitrogen-doped carbon nanotube polyhedral material Co / C-NCNP derived from a core-shell zeolite imidazole framework; (G, H) are TEM images of Co / C-NCNP, showing that most of the Co nanoparticles in Co / C-NCNP are dispersed in the solid core containing the ZIF-67 precursor and are tightly wrapped by the CN shell derived from ZIF-8.
[0069] Figure 3 The XRD patterns of (A) Co / C-NCNP, synthesized core-shell ZIF-67@ZIF-8, simulated ZIF-67, simulated ZIF-8, and Co in Example 1 are shown. XRD analysis further confirmed the successful synthesis of core-shell ZIF-67@ZIF-8. High-temperature pyrolysis of core-shell ZIF-67@ZIF-8 transformed it into Co / C-NCNP. The carbon (002) peak became sharper and narrower, indicating that the higher the pyrolysis temperature, the higher the degree of graphitization of the sample. The Co / C-NCNP material exhibited three characteristic diffraction peaks at 44.15°, 51.44°, and 75.73°, which can be attributed to metallic Co (PDF#15-0806). (B) Infrared spectra of Co / C-NCNP and core-shell ZIF-67@ZIF-8 crystals are shown. Co / C-NCNP exhibits a peak at 1136.8 cm⁻¹. -1 There is a broad absorption peak at 1556.3 cm⁻¹, which is a characteristic peak of the C-C vibration. -1 The presence of a C=C vibrational characteristic peak indicates the formation of a highly graphitized carbon composite material; the nitrogen adsorption / desorption isotherm of (C)Co / C-NCNP exhibits a typical type IV isotherm and a significant hysteresis loop, indicating a rich mesoporous structure. Co / C-NCNP also possesses a large BET specific surface area (184.7 m²). 2 The pore size distribution curves of Co / C-NCNP ( / g) and (D) show that the size of the mesopores in Co / C-NCNP is mainly concentrated at 2.38 and 3.81 nm. The porosity of Co / C-NCNP is beneficial to charge and mass transport in electrochemical sensing.
[0070] Test Example 2
[0071] Electrochemical characterization was performed on (a) bare SPCE, (b) ZIF-67@ZIF-8 / SPCE, (c) ZIF-8-920 / SPCE, (d) ZIF-67-920 / SPCE, (e) Co / C-NCNP / SPCE (without BVC) and (f) Co / C-NCNP / SPCE (with BVC) prepared in Examples 1 and Comparative Examples 3-6.
[0072] Figure 4 The CV curves of electrodes modified with different materials in 50 μM BVC solution show that only Co / C-NCNP / SPCE exhibits the largest BVC redox peak, indicating that Co / C-NCNP has a good catalytic effect on BVC, providing high electron transport efficiency and a large specific surface area for the redox process, thereby increasing the adsorption amount of BVC on the Co / C-NCNP / SPCE surface and the electrochemical redox rate.
[0073] Figure 5 The image shows the CV curves of (A) Co / C-NCNP / SPCE in 0.1M PBS containing 50μM BVC at different pH values (3.0, 4.0, 5.0, 6.0, 7.0) in Example 1. (B) shows the effect on oxidation peak potential and oxidation peak current. As the solution pH increases, the oxidation peak potential shifts negatively, indicating that protons directly participate in the electrode reaction, achieving the maximum response current at pH 5.0. It can also be seen that the oxidation peak potential (E...)... pa The slope of the reaction is linear with pH, and is close to the theoretical value of 0.059V / pH, indicating that the number of electrons transferred in the redox reaction is equal to the number of protons.
[0074] Figure 6 (A) is the CV chromatogram of Co / C-NCNP / SPCE in 0.1M PBS containing 50μM BVC in Example 1 at different scan rates: 20, 50, 75, 100, 120, 150, 200, 250, 300, 350, 400, and 600 mV / s; (B) is... pa I pc With υ 1 / 2 The linear relationship shows that as the scan rate υ increases, the redox peak current gradually increases, and the redox peak current (I0) also increases. pa and I pc ) and υ 1 / 2 It exhibits a good linear relationship, and the linear equation is I. pa (μA)=20.122υ 1 / 2 (mV / s) 1 / 2 -63.544(r 2 =0.996) and I pc(μA)=-11.931υ 1 / 2 (mV / s) 1 / 2 +16.266(r 2 =0.977), indicating that the electrochemical behavior of BVC on Co / C-NCNP / SPCE is a diffusion-controlled process. The redox peak potential (E) shifts with the natural logarithm of the scan rate (lnυ), and the linear regression equations are E pa (μA)=0.0461lnυ(mV / s)-0.00321(r 2 =0.986)andE pc (μA)=-0.0238lnυ(mV / s)+0.202(r 2 =0.983). The electron transfer number (n) and transfer coefficient (α) can be calculated using the Lavignon equation, and αn is calculated to be 0.56. Since the value of α ranges from approximately 0.3 to 0.7, n is approximately 1. The redox electron transfer number of BVC on Co / C-NCNP / SPCE is 1. Furthermore, the potential energy changes with increasing υ, therefore the electrochemical behavior tends to be a quasi-reversible process.
[0075] Test Example 3
[0076] Figure 7 Examples 1 show: (A) DPV curves of different concentrations of BVC (0, 0.15, 0.2, 0.5, 1.0, 5.0, 10.0, 15.0, 20.0, 50.0, 80.0, 100.0 μM) on Co / C-NCNP / SPCE; and (B) the relationship between oxidation peak current and BVC concentration. It was found that the oxidation peak current increases with increasing BVC concentration. The peak current shows a linear relationship between BVC concentration and concentration in the ranges of 0.15-20.0 μM and 20.0-100.0 μM, with corresponding linear regression equations I0 and I0. p =8.347C + 2.398(r) 2 =0.9956) and I p =1.908C + 127.839(r) 2 =0.9999), and a low detection limit of 0.014 μM was obtained based on 3S0 / S.
[0077] Test Example 4
[0078] The reproducibility, selectivity and stability of the Co / C-NCNP / SPCE prepared in Example 1 were studied in BVC solution; the modified electrode was placed in 0.1M PBS (pH 5.0) solution containing 50 μM BVC and scanned using DPV and CV methods.
[0079] Figure 8(A) shows the DPV response of 50.0 μM BVC containing different interfering substances on the Co / C-NCNP / SPCE in Example 1, with 25000.0 μM of interfering substance Na added respectively. + K + Mg 2+ Zn 2+ NO3 - SO4 2- (a) When glycine, alanine, glucose, and interfering substances ascorbic acid, rutin, quercetin, and 6,7-dihydroxycoumarin were added at a concentration of 2500.0 μM, the oxidation peak current of BVC did not change significantly, indicating that the electrochemical sensor has good anti-interference ability. (B) The DPV response of 50.0 μM BVC to 8 independent electrodes (repeated eight times according to the method of Example 1) was measured by CV method in 50.0 μM BVC solution. The change of BVC oxygen reduction peak current was studied. The relative standard deviation was 3.49%, indicating that the prepared electrodes have good reproducibility. (C) CV response of 50 μM BVC after 100 cycles on the Co / C-NCNP / SPCE of Example 1. The relative standard deviation of Co / C-NCNP / SPCE after 100 cycles of CV testing was 1.92%, indicating that the modified electrode has good stability. (D) CV curve after 100 cycles after storage for 30 days. The electrode was stored continuously at 4 °C for 30 days, and CV scans were performed every 2 days in 50.0 μM BVC solution. The redox peak current did not change significantly, indicating that the modified electrode has good long-term stability.
[0080] Test Example 5
[0081] The Co / C-NCNP / SPCE electrochemical sensor prepared in Example 1 was applied to the determination of BVC in real sample *Ligustrum lucidum* pollen using a spiked recovery method. 0.105 g of *Ligustrum lucidum* pollen was weighed and ultrasonically extracted with 10 mL of 0.1 M pH 5.0 PBS for 2 h. The volume was then adjusted to 50 mL with 0.1 M pH 5.0 PBS, and the supernatant was obtained by centrifugation. The BVC content in the sample solution was detected using the DPV method. Furthermore, BVC standards of known concentrations were added to the sample solution, and the Co / C-NCNP / SPCE sensor was used for determination. The results were obtained through linear equation I. p =8.347C + 2.398(r) 2 =0.9956) The BVC content in the spiked sample solution was calculated, and the recovery rate was 96.33-117.00%, with a relative standard deviation of less than 5.0%, indicating that Co / C-NCNP / SPCE can be used to detect the BVC content in real sample *Erigeron breviscapus* pollen.
[0082] In summary, this invention uses a Co / C-NCNP modified electrode (Co / C-NCNP / SPCE) as the working electrode and employs the DPV method to detect BVC. First, the Co / C-NCNP / SPCE is placed in a buffer solution containing different concentrations of BVC. The buffer solution is 0.1M PBS at pH 5.0. As the BVC concentration increases, the redox peak current of BVC also increases accordingly. This is mainly due to the specific catalytic effect, high electron transport efficiency, and large specific surface area of Co / C-NCNP, leading to an increase in BVC adsorption and a significantly accelerated redox rate. A working curve is plotted based on the magnitude of the redox peak current versus the BVC concentration, allowing for the quantitative detection of BVC in the solution. The detection limit of this method is 0.014 μM, and the linear range is 0.15–100.0 μM.
[0083] Selectivity of the Co / C-NCNP / SPCE electrochemical sensor was determined using the DPV method. The method involved stabilizing the prepared Co / C-NCNP / SPCE in 0.1M PBS using the DPV method, adding 50.0 μM BVC analyte and interfering substances, and detecting changes in the oxidation peak current. The interfering substance was Na. + K + Mg 2+ Zn 2+ NO3 - SO4 2- The concentrations of glycine, alanine, and glucose were 25000.0 μM; the concentrations of interfering substances ascorbic acid, rutin, quercetin, and 6,7-dihydroxycoumarin were 2500.0 μM. After the addition of these interfering substances, the oxidation peak current of BVC did not change significantly, indicating that the electrochemical sensor has good selectivity.
[0084] Further reproducibility tests were conducted on the Co / C-NCNP / SPCE electrochemical sensor. Eight Co / C-NCNP / SPCE electrodes prepared under the same conditions were measured using colorimetry (CV) in 50.0 μM BVC solution. The changes in the BVC oxygen reduction peak current were studied, and the relative standard deviation (RSD) was 3.49%, indicating that the prepared electrode has good reproducibility. After 100 cycles of CV testing, the RSD of the Co / C-NCNP / SPCE electrode was 1.92%, indicating good stability. After continuous storage at 4 °C for 30 days, CV scans were performed every two days in 50.0 μM BVC solution. No significant changes in the redox peak current were observed, indicating good long-term stability of the modified electrode.
[0085] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.
Claims
1. An application of a wireless portable sensor in detecting scutellarin, characterized in that, The wireless portable sensor was placed in the analyte containing scutellarin, and the electrochemical signal of scutellarin in the analyte was detected at a potential of -0.2~0.5V using differential pulse voltammetry. The wireless portable sensor uses electrodes modified with core-shell zeolite imidazole framework-derived materials as sensing elements. The preparation method of the core-shell zeolite imidazole framework-derived material modified electrode includes the following steps: 4.376 g Co(NO3)2·6H2O, 4.472 g Zn(NO3)2·6H2O, and 4.988 g 2-methylimidazole were dissolved in 60 mL methanol, 60 mL methanol, and 120 mL methanol, respectively, and sonicated at room temperature for 10 min to obtain homogeneous Co(NO3)2·6H2O, Zn(NO3)2·6H2O, and 2-methylimidazole solutions. The Co(NO3)2·6H2O solution was poured into the 2-methylimidazole solution and stirred for 10 min. Then, the Zn(NO3)2·6H2O solution was poured into the above solution, and stirring was continued for 1 h. The resulting suspension was allowed to stand for 12 h, the precipitate was washed with methanol, centrifuged three times at 8000 rpm, and then dried at 85 ℃ for 5 h to obtain core-shell ZIF-67@ZIF-8. The prepared core-shell ZIF-67@ZIF-8 was placed in a tube furnace and pyrolyzed at 920 °C under an argon atmosphere at a heating rate of 5 °C / min for 4 h to prepare Co / C-NCNP. The prepared Co / C-NCNP was dispersed in ultrapure water to obtain a Co / C-NCNP suspension with a concentration of 2.0 mg / mL. 20 μL of the Co / C-NCNP suspension was drop-coated onto the working electrode surface of the SPCE and dried at room temperature to obtain a modified electrode based on nitrogen-doped carbon nanotube polyhedral material derived from a core-shell zeolite imidazole framework.