NGR / GCDs nanocomposite modified electrode and preparation method and application thereof

Abstract

The invention provides an NGR / GCDs nanocomposite modified electrode and a preparation method and application thereof, and belongs to the technical field of electrochemical sensors. The preparation method of the NGR / GCDs nanocomposite modified electrode comprises the following steps: centrifuging graphdiyne dispersion liquid, and collecting supernate to obtain graphdiyne carbon dots; coating the surface of a substrate electrode with the nitrogen-doped graphene dispersion liquid, and drying to obtain an NGR modified electrode; and coating the graphdiyne carbon dots on the surface of the NGR modified electrode, and drying to obtain the modified electrode. According to the invention, NGR and GCDs are modified on a substrate electrode, and a portable electrochemical workstation is combined to construct an intelligent electrochemical sensor for detecting scopoletin. The modified electrode provided by the invention has good sensitivity, stability, reproducibility and selectivity, and provides a new method and a new material for the fields of medical health, drug detection and cancer treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical sensors, and in particular to an NGR / GCDs nanocomposite material modified electrode and a preparation method and application thereof. Background Art

[0002] The increasing demand for biochemical information from sample samples has led to a growing demand for decentralized and mobile analytical laboratories, a major driver of research in wireless chemical sensors. Wireless chemical sensor research is rapidly developing due to its ability to analyze target substances outside of specialized laboratories, ensuring timely and convenient access to on-site data. Furthermore, wireless chemical sensors are gaining increasing attention from researchers and the public due to their low cost, ease of operation, and simplicity. In electrochemical sensors, the working electrode is a crucial component for achieving sensitive and rapid sensing, making the selection of appropriate electrode modification materials crucial. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a NGR / GCDs nanocomposite modified electrode and its preparation method and application.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] One of the technical solutions of the present invention is a method for preparing an NGR / GCDs nanocomposite modified electrode, comprising the following steps:

[0006] The Graphdene (GDY) dispersion was centrifuged and the supernatant was collected to obtain Graphdene carbon dots (GCDs);

[0007] The nitrogen-doped graphene (NGR) dispersion was coated on the surface of the base electrode and dried to obtain the NGR modified electrode;

[0008] The graphyne carbon dots are coated on the surface of the NGR modified electrode and dried to obtain the NGR / GCDs nanocomposite material modified electrode.

[0009] The second technical solution of the present invention is a NGR / GCDs nanocomposite modified electrode prepared by the above preparation method.

[0010] The third technical solution of the present invention is an electrochemical sensor, wherein the working electrode is the NGR / GCDs nanocomposite modified electrode.

[0011] A fourth technical solution of the present invention is a use of the above-mentioned NGR / GCDs nanocomposite modified electrode or the above-mentioned electrochemical sensor in detecting scopoletin.

[0012] The present invention discloses the following technical effects:

[0013] The present invention uses graphene carbon dots (GCDs) as a carbon source and nitrogen-doped graphene (NGR) as a nitrogen source. NGR and GCDs are modified on a substrate electrode and combined with a portable electrochemical workstation to construct an intelligent electrochemical sensor for detecting scopoletin. The constructed electrochemical sensor exhibits a low detection limit of 4.76nM (3S0 / S). Scanning electron microscopy and transmission electron microscopy observations show that the NGR / GCDs material is uniformly dispersed and has a thin, gauze-like appearance. This provides more attachment sites, electron transport channels, and an effective electrochemical surface area, thereby improving the catalytic effect of the NGR / GCDs on scopoletin on the sensing surface.

[0014] The modified electrode provided by the present invention has excellent sensitivity, stability, reproducibility, and selectivity. It also improves the catalytic activity of the catalyst in the detection of scopoletin. It provides new methods and materials for the fields of medical health, drug testing, and cancer treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 is a scanning electron microscope (SEM) photograph of NGR without ultrasound;

[0017] Figure 2 This is a scanning electron microscope (SEM) photograph of NGR subjected to ultrasound for 3 h in step (2) of Example 1;

[0018] Figure 3 This is a scanning electron microscope (SEM) photograph of NGR ultrasonicated for 6 hours in step (2) of Example 2;

[0019] Figure 4 This is the SEM of NGR at different magnifications under ultrasound for 12 h in step (2) of Example 3;

[0020] Figure 5 TEM images of NGR at different magnifications;

[0021] Figure 6 This is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of NGR;

[0022] Figure 7 TEM images of GCDs at different magnifications;

[0023] Figure 8 High-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) images of GCDs;

[0024] Figure 9 TEM images and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) images of GCDs-NGR in the modified electrode of Example 1 at different magnifications;

[0025] Figure 10 GCDs / NGR / SPE with different bending degrees and their corresponding 10-cycle multi-scan CV graphs;

[0026] Figure 11 CV curves of 10 μM scopoletin on different modified electrodes;

[0027] Figure 12 CV curves of different modified electrodes in 0.05 M pH 7.0 PBS;

[0028] Figure 13 CV curves of GCDs / NGR / SPE in 0.05 M PBS at different pH values;

[0029] Figure 14 is the linear relationship between Epa and pH;

[0030] Figure 15 is the relationship between Ipa and υ;

[0031] Figure 16 is the relationship between Epa and ln υ;

[0032] Figure 17 are the three adsorption configurations of scopoletin and GCDs;

[0033] Figure 18 The O group of scopoletin binds to GCDs;

[0034] Figure 19 The scopoletin molecules bind to GCDs in parallel;

[0035] Figure 20 DPV curves of scopoletin standard solutions with different concentrations on GCDs / NGR / SPE;

[0036] Figure 21 is the linear relationship diagram between Ipa and low concentration scopoletin standard solution;

[0037] Figure 22 is the linear relationship diagram between Ipa and high concentration scopoletin standard solution;

[0038] Figure 23 DPV curves of different substances at 100 μM on GCDs / NGR / SPE. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0041] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0042] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0043] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0044] The first aspect of the present invention provides a method for preparing an NGR / GCDs nanocomposite modified electrode, comprising the following steps:

[0045] The graphyne dispersion is centrifuged, and the supernatant is collected to obtain graphyne carbon dots;

[0046] The nitrogen-doped graphene dispersion is coated on the surface of the base electrode and dried to obtain an NGR modified electrode;

[0047] The graphyne carbon dots are coated on the surface of the NGR modified electrode and dried to obtain the NGR / GCDs nanocomposite material modified electrode.

[0048] In the present invention, if the coating order of the gydnylon carbon dots and the nitrogen-doped graphene dispersion is adjusted, the current response of the obtained modified electrode will be reduced.

[0049] In a preferred embodiment of the present invention, the concentration of graphyne in the graphyne dispersion is 0.5 to 2.0 mg / mL, specifically 0.5 mg / mL, 1.0 mg / mL or 2.0 mg / mL.

[0050] In a preferred embodiment of the present invention, the preparation method of the graphyne dispersion is: dispersing GDY in ultrapure water, and ultrasonically treating it to obtain a GDY dispersion; the ultrasonic treatment time is 12-24 hours (specifically, 12 hours, 16 hours, 20 hours or 24 hours).

[0051] In a preferred embodiment of the present invention, the concentration of nitrogen-doped graphene in the nitrogen-doped graphene dispersion is 0.25 to 1.0 mg / mL, specifically 0.25 mg / mL, 0.5 mg / mL or 1.0 mg / mL.

[0052] In a preferred embodiment of the present invention, the preparation method of the nitrogen-doped graphene dispersion is: dispersing nitrogen-doped graphene in ultrapure water, and ultrasonically treating it for 3-12 hours (specifically, 3 hours, 6 hours or 12 hours) to obtain the nitrogen-doped graphene dispersion.

[0053] The present invention does not impose any particular restrictions on the amount of graphyne dispersion and nitrogen-doped graphene dispersion applied, as long as the amount applied is sufficient to completely coat the surface of the substrate electrode. The present invention does not impose any particular restrictions on the coating method, and conventional techniques used by those skilled in the art, such as drop coating, may be used.

[0054] The present invention does not impose any particular limitation on the selection of the substrate electrode, and any substrate electrode well known to those skilled in the art may be selected, such as SPE.

[0055] In a preferred embodiment of the present invention, the volume ratio of the graphyne dispersion to the nitrogen-doped graphene dispersion is (1-4):2. Specifically, it is 1:1, 2:1 or 1:2.

[0056] The second aspect of the present invention provides an NGR / GCDs nanocomposite modified electrode prepared by the above preparation method.

[0057] The third aspect of the present invention provides an electrochemical sensor as described above, wherein the working electrode is the NGR / GCDs nanocomposite material modified electrode.

[0058] A fourth aspect of the present invention provides a use of the NGR / GCDs nanocomposite modified electrode or the electrochemical sensor in detecting scopoletin.

[0059] The present invention does not impose any particular limitation on the sources of graphyne and nitrogen-doped graphene. Products available on the market or prepared using methods well known to those skilled in the art are all suitable for the present invention.

[0060] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or are publicly available.

[0061] In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

[0062] Example 1

[0063] The preparation steps of GCDs / NGR-3 / SPE are as follows:

[0064] Step (1) 10.0 mg of GDY was weighed and dispersed in 10.0 mL of ultrapure water, and the mixture was continuously ultrasonicated for 24 h to obtain a GDY dispersion; the GDY dispersion was placed in a centrifuge tube, centrifuged at 8000 rpm for 5 min, and the supernatant was collected to obtain graphene carbon dots (GCDs), which were stored at room temperature for later use;

[0065] Step (2) 5.0 mg of NGR was weighed and dispersed in 10.0 mL of ultrapure water, and continuous ultrasonication was performed for 3 h to obtain a uniformly dispersed NGR solution;

[0066] Step (3) Pipette 20.0 μL of NGR solution onto the SPE surface and dry at room temperature to obtain the modified electrode NGR / SPE. Continue to pipette 20.0 μL of GCDs solution onto the NGR / SPE surface and dry at room temperature to obtain the modified electrode GCDs / NGR-3 / SPE.

[0067] Example 2

[0068] The only difference from Example 1 is that the ultrasonic treatment for 3 h in step (2) is replaced by ultrasonic treatment for 6 h, and the other steps and parameters are the same as those in Example 1. GCDs / NGR-6 / SPE is obtained.

[0069] Example 3

[0070] The only difference from Example 1 is that the ultrasonic treatment for 3 h in step (2) is replaced by ultrasonic treatment for 12 h, and the other steps and parameters are the same as those in Example 1. GCDs / NGR-12 / SPE is obtained.

[0071] Electrochemical test conditions

[0072] The modified electrodes were characterized by electrochemical impedance spectroscopy (EIS) in a mixed solution of 10.0 mM K3[Fe(CN)6] and 0.1 M KCl. The electrochemical performance of the modified electrodes was tested by cyclic voltammetry (CV) in a mixed solution of 1.0 mM K3[Fe(CN)6] and 0.5 M KCl at a scan rate of 100 mV s -1 The target molecules were electrochemically analyzed in 0.05 M PBS using chronocoulometry (CC) and differential pulse voltammetry (DPV). The solution was deoxygenated by passing high-purity N2 for 30 min before testing.

[0073] Actual sample pretreatment

[0074] 19.0 g of ripe noni fruit pulp and 15.0 mL of enzyme were placed in separate centrifuge tubes, diluted to 50.0 mL with methanol, and sonicated for 30 minutes. The noni solution was centrifuged at 8000 rpm for 5 minutes, and the supernatant was filtered through a 0.45 μm nylon syringe filter. The enzyme solution was filtered directly. Both sample solutions were then diluted with PBS buffer at a ratio of 1:1000 to obtain the noni sample and enzyme sample solutions, respectively.

[0075] DFT calculation method

[0076] Density functional theory (DFT) calculations were performed using Gussian09 software, and B3LYP / 6-311G(d) was used to optimize the geometry of scopoletin adsorption on the surface of gydnyle carbon dots.

[0077] Test results:

[0078] Figure 1 is a scanning electron microscope (SEM) photograph of NGR without ultrasound; Figure 1 It can be seen that when there is no ultrasonic treatment, NGR presents a curled and agglomerated mushroom cloud shape.

[0079] Figure 2 is a scanning electron microscope (SEM) photograph of NGR subjected to ultrasound for 3 h in step (2) of Example 1; Figure 2 It can be seen that after 3 h of ultrasound, the originally agglomerated NGR became loose and began to show the layered structure of graphene.

[0080] Figure 3 is a scanning electron microscope (SEM) photograph of NGR subjected to ultrasound for 6 h in step (2) of Example 2; Figure 3 It can be seen that after 6 h of ultrasound, NGR begins to show typical morphological characteristics of graphene.

[0081] Figure 4 The SEM images of NGR at different magnifications under ultrasound for 12 h in step (2) of Example 3 are shown; Figure 4 It can be seen that when the ultrasonic time is 12 h, the gauze-like NGR can be seen to be uniformly dispersed, and the NGR with a large specific surface area can provide more attachment sites for the fixation of the analyzed substances.

[0082] Figure 5 TEM images of NGR at different magnifications after 3 h of ultrasound in Example 1; Figure 5 It can be seen that NGR is evenly dispersed and appears as a thin layer of gauze mist.

[0083] Figure 6 is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) image of NGR after 3 hours of ultrasound in Example 1; Figure 6 It can be seen that the lattice fringe spacing of NGR is 0.341 nm.

[0084] Figure 7 TEM images of GCDs at different magnifications after ultrasonic treatment in Example 1; Figure 7 It can be seen that the size of GCDs is below 10.0 nm.

[0085] Figure 8 is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) image of GCDs after ultrasonic treatment in Example 1; Figure 8 It can be seen that the lattice spacing is 0.361 nm.

[0086] Figure 9 TEM images and high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) images of GCDs-NGR in the modified electrode of Example 1 at different magnifications; Figure 9 It can be seen that GCDs particles are evenly dispersed on the surface of the thin layer of NGR.

[0087] Figure 10 The GCDs / NGR / SPE with different bending degrees and their corresponding 10-cycle multi-scan CV graphs of Example 1; Figure 10 After 10 scans, the relative standard deviations (RSDs) of the current values ​​for each electrode were 1.27%, 0.78%, 0.81%, and 1.11%, respectively. Furthermore, the current values ​​for the four electrodes remained nearly consistent. These results demonstrate that while increased pressure on both sides of the electrode increases the degree of bending of the modified electrode, this does not affect the stability of the GCDs / NGR / SPE.

[0088] Figure 11 CV curves of 10 μM scopoletin on different modified electrodes (a: SPE, b: NGR modified SPE under ultrasound at 0 h, 3 h, 6 h, 12 h, f: GCDs / NGR / SPE of Example 1); Figure 11 It can be seen that the oxidation peak current on SPE (curve a) is the smallest. As the ultrasonic time of the NGR dispersion increases, the oxidation peak current of NGR / SPE gradually increases (curve b-curve e). This shows that the increase in ultrasonic time is conducive to the dispersion of NGR, and the uniformly dispersed nanosheets obtained have a larger specific surface area, which can provide a larger loading interface for scopolamine. At the same time, the presence of NGR can also increase the electron transfer rate of the electrode. This is because the zero-bandgap GR itself has high conductivity, and the doping of nitrogen atoms helps to increase the specific surface area. The oxidation peak current value on GCDs / NGR / SPE (curve f) is the highest, indicating that the GCDs-NGR nanocomposite material has brought into play the advantages of both materials and has a good synergistic effect.

[0089] Figure 12 CV curves of different modified electrodes in 0.05M pH 7.0 PBS; Figure 12 It can be seen that no redox peaks appear in the CV curves of SPE in PBS (curve a) and GCDs / NGR / SPE in Example 1 (curve c); however, obvious oxidation peaks appear in the CV curves of 10.0 μM scopoletin solution in SPE (curve b) and GCDs / NGR / SPE in Example 1 (curve d), indicating that scopoletin can undergo direct electrochemical behavior on the electrode surface.

[0090] Figure 13 CV curves of GCDs / NGR / SPE in 0.05M PBS at different pH values ​​of Example 1; Figure 13 As shown above, the oxidation peak current (Ipa) gradually increases as the pH increases to 7.0, but Ipa decreases as the pH continues to increase. Therefore, 7.0 is selected as the optimal pH value. The oxidation peak potential (Epa) gradually shifts negatively with increasing pH, indicating the participation of protons in the reaction.

[0091] Figure 14 is the linear relationship between Epa and pH on the modified electrode surface of Example 1; Figure 14 It can be seen that the peak potential of scopoletin and pH show a good linear relationship. The linear regression equation is Epa (V) = 0.055pH + 0.91 (γ = 0.993), and the slope is 55mVpH -1 Close to the theoretical value of 59mVpH -1 . This shows that an equal number of electrons and protons participate in the oxidation reaction.

[0092] Figure 15 is the relationship between the modified electrode surface Ipa and υ in Example 1; Figure 15It can be calculated that Ipa increases with the increase of scanning speed υ, and has a good linear relationship. The linear regression equation is Ipa (μA) = 38.36υ (Vs -1 )+1.142(γ=0.991), which indicates that scopoletin undergoes an adsorption-controlled reaction on GCDs / NGR / SPE. It is speculated that GCDs-NGR not only has a large specific surface area, but also the large π-conjugated structure of GCDs can form non-covalent bonds with the lone pair electrons of the hydroxyl group of the target molecule, thereby adsorbing more scopoletin molecules.

[0093] Figure 16 is the relationship between the modified electrode surface Epa and ln υ of Example 1; Figure 16 It can be seen that there is a good linear relationship between the oxidation peak potential and ln υ, and the regression equation is Epa (V) = 0.1086ln υ (V s -1 )+0.6649(γ=0.989).

[0094] Figure 17 There are three adsorption configurations of scopoletin and GCDs: OH group of scopoletin binds to GCDs; Figure 17 It can be seen that the binding of OH group of scopoletin to GCDs has the most stable geometric structure.

[0095] Figure 18 The O group of scopoletin binds to GCDs; Figure 18 It can be seen that the binding of the O group of scopoletin with GCDs cannot converge, indicating that the configuration is unreasonable, and therefore a stable configuration cannot be obtained.

[0096] Figure 19 Scopolamine molecules bind to GCDs in parallel; Figure 19 It can be seen that during the geometry optimization process, the configuration of the scopoletin molecule binding to GCDs in parallel gradually flipped and finally transformed into the configuration in which the scopoletin OH group bound to GCDs.

[0097] Figure 20 is the DPV curve of scopoletin standard solution with different concentrations on GCDs / NGR / SPE of Example 1; Figure 20 It can be seen that the Ipa value increases with the increase of concentration and has a good linear relationship.

[0098] Figure 21 is a linear relationship diagram of the modified electrode surface Ipa of Example 1 and the low concentration scopoletin standard solution; Figure 21 It can be seen that when the concentration (C) of the standard solution is in the range of 0.01 μM-10.0 μM, the linear regression equation of Ipa and C is Ipa (μA) = 0.79C (μM) + 6.94 (γ = 0.997).

[0099] Figure 22 is a linear relationship diagram of the modified electrode surface Ipa of Example 1 and the high concentration scopoletin standard solution; Figure 22 It can be seen that when the concentration of the standard solution is in the range of 10.0-1000 μM, the linear regression equation of Ipa and C is Ipa(μA)=0.29C(μM)+11.97(γ=0.996), indicating that the wireless chemical sensor has a wide detection range and a low detection limit (4.76 nM, 3S0 / S).

[0100] Figure 23 DPV curves of 100 μM scopoletin (a), 6,7-dihydroxycoumarin (b), 7-hydroxycoumarin (c), bisphenol A (d), rutin (e), quercetin (f) and dopamine (g) on ​​the GCDs / NGR / SPE of Example 1; Figure 23 It can be seen that the oxidation peak potential of scopoletin is 0.49 V (curve a), which is different from 0.3 V (b) of 6,7-dihydroxycoumarin, 0.69 V (c) of 7-hydroxycoumarin, 0.59 V (d) of bisphenol A, 0.27 V (e) of rutin, 0.13 V and 0.35 V (f) of quercetin, and 0.15 V and 0.70 V (g) of dopamine. It can be seen that the difference between the oxidation peak potentials of these interfering substances and GCDs / NGR / SPE is sufficient to prove that the detection method has good anti-interference ability.

[0101] Table 1 compares the results of GCDs / NGR / SPE and HPLC for the detection of scopoletin in actual samples from Example 1. Analysis of the table shows that the recoveries of the two samples obtained using the standard addition method were 94.0% and 104.0%, respectively, with RSDs within 5%. This result is consistent with the results of the HPLC method.

[0102] Table 1

[0103]

[0104] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an NGR / GCDs nanocomposite modified electrode, characterized in that: The following steps are involved: The graphyne dispersion is centrifuged, and the supernatant is collected to obtain graphyne carbon dots; The nitrogen-doped graphene dispersion is coated on the surface of the base electrode and dried to obtain an NGR modified electrode; The graphyne carbon dots are coated on the surface of the NGR modified electrode and dried to obtain the NGR / GCDs nanocomposite material modified electrode.

2. The preparation method according to claim 1, characterized in that The concentration of graphyne in the graphyne dispersion is 0.5-2.0 mg / mL.

3. The preparation method according to claim 1, characterized in that The concentration of nitrogen-doped graphene in the nitrogen-doped graphene dispersion is 0.25-1.0 mg / mL.

4. The preparation method according to claim 1, characterized in that The preparation method of the nitrogen-doped graphene dispersion comprises the following steps: dispersing the nitrogen-doped graphene in ultrapure water, and ultrasonically treating the water for 3-12 hours to obtain the nitrogen-doped graphene dispersion.

5. The preparation method according to claim 1, characterized in that The volume ratio of the graphyne dispersion liquid to the nitrogen-doped graphene dispersion liquid is (1-4):

2.

6. An NGR / GCDs nanocomposite modified electrode prepared by the preparation method according to any one of claims 1 to 5.

7. An electrochemical sensor, characterized in that The working electrode is the NGR / GCDs nanocomposite modified electrode according to claim 6.

8. Use of the NGR / GCDs nanocomposite modified electrode according to claim 6 or the electrochemical sensor according to claim 7 in detecting scopoletin.

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