Electrode modification material for riboflavin detection and analysis and preparation method thereof

Abstract

The present invention belongs to the field of electrochemical detection technology, and in particular, relates to an electrode modification material for riboflavin detection and analysis and a preparation method thereof. The present invention uses graphene oxide (rGO) and cerium dioxide (CeO2) nanoparticles to prepare the modification material, and jointly modify the electrode. The modification material combines the characteristics of high electron mobility of graphene oxide and catalytic activity of cerium dioxide nanoparticles, and uses an electrochemical method to detect the riboflavin content in the solution. It can not only quickly and accurately detect the riboflavin content, but also overcome the shortcomings of traditional large-scale detection equipment, such as cumbersome operation steps, expensive instruments, and inconvenient to carry. In addition, the preparation method is simple and convenient, the detection is fast, and it is easy to control, and it has excellent application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemical detection, and in particular to an electrode modification material for riboflavin detection and analysis and a preparation method thereof. Background Art

[0002] Riboflavin (vitamin B2) is an essential substance for the human body, but the human body cannot synthesize it on its own and needs to obtain sufficient intake through diet. Riboflavin deficiency can cause autoimmune diseases such as itching, stinging eyes, stinging tongue, stomatitis, congestion, etc. Therefore, riboflavin levels in food and medicine need to be monitored.

[0003] Riboflavin (RF) content has been detected by a variety of techniques, including high performance liquid chromatography (HPLC), electrochemiluminescence, laser-induced fluorescence, spectroelectrochemistry, capillary electrophoresis, and flow injection analysis with spectrophotometric detection. However, the above techniques have some disadvantages, including: (1) high cost; (2) time-consuming; (3) use of large amounts of organic solvents; (4) complex operation procedures. For example, although HPLC is fast and accurate, it requires a large number of modules, columns, and different mobile phases. These procedures usually involve some kind of chemical reaction or separation procedure and require high technical skills of the operator.

[0004] Electrochemical analysis methods have the advantages of fast analysis speed, simple operation process, high sensitivity, strong flexibility, strong selectivity, low price, and easy operation in laboratory environment. The prerequisite for using electrochemical analysis methods to determine riboflavin is to find suitable electrode materials. Studies have found that unmodified bare electrodes have disadvantages such as low sensitivity, poor selectivity, slow electron transfer rate, high overpotential, and easy scaling of electrodes when performing electrochemical determination of target analytes. Summary of the invention

[0005] The purpose of the present invention is to provide an electrode modification material for riboflavin detection and analysis and a preparation method thereof. The modification material is prepared by using graphene oxide (rGO) and cerium dioxide (CeO2) nanoparticles to jointly modify the electrode. The modification material combines the characteristics of high electron mobility of graphene oxide and catalytic activity of cerium dioxide nanoparticles. By using the electrode modification material modified by the present invention to modify the electrode, the riboflavin content can be easily determined by electrochemical technology, thereby realizing rapid and accurate detection of the riboflavin content, and also overcoming the shortcomings of traditional large-scale detection equipment, such as complicated operation steps, expensive instruments, and inconvenient carrying.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide an electrode modification material for riboflavin detection, wherein the effective components of the electrode modification material include graphene oxide and CeO2 nanoparticles;

[0008] The mass ratio of the graphene oxide to the CeO2 nanoparticles is 0.5-3:3-15.

[0009] Furthermore, the electrode modification material also includes Nafion.

[0010] The second technical solution of the present invention is to provide a method for preparing the electrode modification material for riboflavin detection, the steps comprising:

[0011] The electrode modification material is obtained by uniformly dispersing graphene oxide and CeO2 nanoparticles in a solvent.

[0012] Furthermore, the concentration of graphene oxide in the electrode modification material is 0.5-3 g / L, and the concentration of CeO2 nanoparticles is 3-15 g / L.

[0013] Preferably, the mass ratio of the graphene oxide to the CeO2 nanoparticles is 1:5.

[0014] Furthermore, the solvent is water or ethanol solution

[0015] Preferably, the mass fraction of the ethanol solution is 80% to 100%.

[0016] Furthermore, the electrode modification material also includes a Nafion solution with a concentration of 5 wt.%.

[0017] Preferably, the amount of the Nafion solution added to the electrode modification material is 0-5 μL / L.

[0018] The present invention adds Nafion solution to the electrode modification material, which can improve the firmness of the electrode surface modification. The principle is that Nafion solution is a perfluorosulfonic acid polymer that can promote the formation of an interface network. The amount of Nafion added needs to be moderate to ensure a balance between the firmness of the electrode surface modification and the catalytic reaction efficiency.

[0019] The third technical solution of the present invention is to provide an application of the above-mentioned electrode modification material in riboflavin detection.

[0020] The fourth technical solution of the present invention is to provide an electrode for riboflavin detection, wherein the electrode has the above-mentioned electrode modification material as a surface coating.

[0021] A fifth technical solution of the present invention is to provide a method for preparing the electrode for riboflavin detection, the steps comprising:

[0022] The electrode modification material is drop-coated on the surface of the working electrode to form a coating, and then blown dry to obtain the electrode for riboflavin detection.

[0023] Furthermore, the working electrode is a glassy carbon electrode.

[0024] Furthermore, the drop coating amount of the electrode modification material is 0.25-0.51 μL / mm 2 .

[0025] Technical solution six of the present invention: provides an application of the above-mentioned electrode for riboflavin detection in riboflavin detection.

[0026] Furthermore, the application method is: using the above electrode as the working electrode, the platinum electrode as the counter electrode, and Ag / AgCl as the reference electrode, a three-electrode electrochemical system is constructed to detect the riboflavin content in the sample to be tested.

[0027] Preferably, the riboflavin-containing sample to be tested needs to be dissolved in PBS for riboflavin detection, and the concentration of the PBS is 0.1-0.2M and the pH is 5-7.

[0028] More preferably, the method further includes a riboflavin pre-enrichment step before riboflavin detection, and the pre-enrichment time is 0 to 90 minutes, and the time is not 0.

[0029] In the present invention, the pre-enrichment operation is performed by using the working electrode to stir or immerse the sample to be tested. The pre-enrichment can allow the test substance to be better enriched on the surface of the modified electrode, thereby improving the sensitivity of detection.

[0030] Technical solution seven of the present invention: provides a method for electrochemically detecting riboflavin in a sample, after modifying the working electrode with the above-mentioned electrode modification material, electrochemically detecting the riboflavin in the sample using a three-electrode system.

[0031] Technical solution eight of the present invention: provides a method for improving the sensitivity of electrochemical detection of riboflavin, after modifying the working electrode with the above-mentioned electrode modification material, electrochemical detection of riboflavin in the sample is performed using a three-electrode system.

[0032] The ninth technical solution of the present invention is to provide a method for reducing the detection limit of riboflavin in electrochemical detection. After modifying the working electrode with the above-mentioned electrode modification material, a three-electrode system is used to electrochemically detect riboflavin in the sample.

[0033] The present invention adopts a three-electrode system to perform electrochemical detection on riboflavin in a sample. After preparing a modified material by composite graphene oxide and cerium dioxide nanoparticles, a relatively uniform gray-black coating is prepared by a drop coating method, which can provide a method for improving detection performance, expand the detection range to 6nM~0.1mM, and the detection limit is 6nM, thereby expanding the application range of the modified electrode.

[0034] The present invention discloses the following technical effects:

[0035] The present invention uses graphene oxide and cerium dioxide nanoparticles to prepare electrode modification materials, and the working electrode coating is modified. Graphene oxide can effectively improve the electron transfer rate, and cerium dioxide has electrocatalytic activity, which effectively solves the problem of insufficient sensitivity of traditional bare electrodes, breaks the limitations of large-scale equipment for detecting riboflavin, improves the detection efficiency and accuracy of riboflavin content, significantly reduces the detection limit of riboflavin detection, makes the detection results more accurate, and expands the concentration range of detection. The material preparation method is simple and convenient, the detection is fast, and it is easy to control, and has excellent application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0037] Figure 1 This is a physical picture of the electrode prepared in Example 1;

[0038] Figure 2 The SEM image and EDS image of the electrode surface prepared in Example 1, wherein (a) is the SEM image, and (b) to (d) are EDS images;

[0039] Figure 3 This is a comparison diagram of DPV detection signals of the electrode prepared in Example 1 of the present invention and BGCE;

[0040] Figure 4 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 2 of the present invention and BGCE;

[0041] Figure 5 This is a DPV diagram of the electrode prepared in Example 2 of the present invention detecting a low concentration (6 nM) riboflavin solution;

[0042] Figure 6 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 3 of the present invention and BGCE;

[0043] Figure 7 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 4 of the present invention and BGCE;

[0044] Figure 8 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 5 of the present invention and BGCE;

[0045] Fig. 9 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 6 of the present invention and BGCE;

[0046] Fig.10 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 7 of the present invention and BGCE;

[0047] Fig.11 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 8 of the present invention and BGCE;

[0048] Fig.12 This is a comparison diagram of DPV detection signals between the electrode prepared in Example 9 of the present invention and BGCE;

[0049] Fig.13 DPV graphs of the linear range of riboflavin detection by the electrode prepared in Example 9 of the present invention, wherein (a) is a comparison of DPV detection signals of the electrode prepared in Example 9 in 0.5μM, 1μM, and 2μM RF solutions; (b) is a comparison of DPV detection signals of the electrode prepared in Example 9 in 3μM, 4μM, and 5μM RF solutions; (c) is a comparison of DPV detection signals of the electrode prepared in Example 9 in 7μM, 9μM, and 13μM RF solutions; (d) is a comparison of DPV detection signals of the electrode prepared in Example 9 in 15μM, 19μM, and 43μM RF solutions; (e) is a comparison of DPV detection signals of the electrode prepared in Example 9 in 53μM and 73μM RF solutions; (f) is a peak current fitting curve of the DPV detection signal of the electrode prepared in Example 9 in 0.5μM-73μM RF solution;

[0050] Fig.14 This is a columnar comparison chart of the peak values ​​of the electrode prepared in Example 9 of the present invention when doped with different heteroatoms and when not doped;

[0051] Fig.15 This is a comparison diagram of DPV detection signals of the electrode pair 53 μM RF solution prepared in Example 9 of the present invention and the 53 μM RF solution prepared with actual medicines;

[0052] Fig.16This is a comparison diagram of CV detection signals of the electrode prepared in Example 9 of the present invention and BGCE in potassium ferrocyanide solution;

[0053] Fig.17 This is a comparison diagram of EIS detection signals of the electrode prepared in Example 9 of the present invention and BGCE in potassium ferrocyanide solution;

[0054] Fig.18 This is a comparison diagram of DPV detection signals of the electrode prepared in Example 10 of the present invention and BGCE;

[0055] Fig.19 This is a comparison diagram of DPV detection signals of the electrode prepared in Comparative Example 1 of the present invention and BGCE;

[0056] Fig. 20 This is a comparison diagram of DPV detection signals of electrodes prepared in Example 2 of the present invention and Comparative Example 2;

[0057] Fig.21 This is a comparison chart of DPV detection signals of electrodes prepared in Example 8 of the present invention and Comparative Example 3. DETAILED DESCRIPTION

[0058] 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 should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0059] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0060] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation 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 a conflict with any incorporated document, the content of this specification shall prevail.

[0061] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0062] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0063] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products.

[0064] The diameter of the glassy carbon electrode used in the specific embodiment of the present invention is 8 mm (the diameter of the built-in glassy carbon core is 5 mm), and the specifications of the platinum electrode used are 25 mm×25 mm×0.2 mm.

[0065] The graphene oxide used in the embodiment of the present invention comes from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., with a thickness of 1~2nm and a sheet diameter of 10-20μm; CeO2 nanoparticles come from Shanghai McLean Biochemical Technology Co., Ltd., with a particle size of 20nm~50nm spherical; Nafion solution comes from DuPont DuPont, model D-520, resin solid content 5wt.%; VB2 drug comes from Shanxi Taiyuan Pharmaceutical Co., Ltd.

[0066] Example 1

[0067] The preparation steps of the electrode for riboflavin detection are:

[0068] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0069] S2, adding 0.003 g of graphene oxide and 0.015 g of CeO2 nanoparticles into 0.001 L of ethanol solution (mass fraction 100%), and ultrasonicating for 30 min to make them dispersed evenly to obtain an electrode modification material;

[0070] S3. Take 10 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0071] Figure 1 This is a physical picture of the electrode prepared in Example 1. Figure 1 It can be seen that the coating of the modified part is gray-black.

[0072] Figure 2The SEM and EDS images of the electrode surface prepared in Example 1, where (a) is the SEM image and (b) to (d) are EDS images. Figure 2 It can be seen that graphene oxide and cerium dioxide nanoparticles are co-modified on the electrode surface.

[0073] The electrode prepared in Example 1 and the glassy carbon electrode (BGCE) in step S1 of Example 1 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode to compare the DPV detection signals of a 0.1 mM RF solution (the solvent was 0.2 M PBS at pH = 7). The results are shown in FIG. Figure 3 As shown in Figure 2, it can be found that the detection signal of the electrode coated with the electrode modification material for 0.1 mM RF reaches 5.26×10 -4 A, BGCE electrode signal (2.91×10 -4 A) Compared with the conventional electrodes, the detection sensitivity of the electrodes coated with modified materials to riboflavin is significantly improved.

[0074] Example 2

[0075] The preparation steps of the electrode for riboflavin detection are:

[0076] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0077] S2, adding 0.001 g of graphene oxide and 0.01 g of CeO2 nanoparticles into 0.001 L of ethanol solution (mass fraction 100%), and ultrasonicating for 30 min to make them dispersed evenly to obtain an electrode modification material;

[0078] S3. Take 8 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0079] The electrode prepared in Example 2 and the glassy carbon electrode (BGCE) in step S1 of Example 2 were respectively used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode.

[0080] The working electrode was stirred in a 5 μM RF solution (solvent: 0.1 M PBS at pH = 5) for 20 min (pre-enrichment treatment), and then the differential pulse (DPV) detection signals were compared. The results are shown in Figure 2. Figure 4 As shown in FIG. 2 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 2 for 5 μM RF reaches 3.99×10 -4 A, BGCE electrode signal (2.77×10 -4A) Compared with the modified materials, the detection sensitivity of riboflavin can be significantly enhanced.

[0081] The working electrode was stirred and pre-enriched in 6 nM RF (solvent was 0.2 M PBS at pH = 7) for 20 min, and then the differential pulse (DPV) detection signal was detected. The electrode coated with the electrode modification material responded to 6 nM RF (solvent was 0.2 M PBS at pH = 7), such as Figure 5 As shown, it is explained that the electrode coated with the electrode modification material in Example 2 can still detect extremely low concentrations of riboflavin.

[0082] Example 3

[0083] The preparation steps of the electrode for riboflavin detection are:

[0084] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0085] S2, adding 0.001 g of graphene oxide and 0.005 g of CeO2 nanoparticles into 0.001 L of ethanol solution (mass fraction 100%), and ultrasonicating for 30 min to make them dispersed evenly to obtain an electrode modification material;

[0086] S3. Take 8 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0087] The electrode prepared in Example 3 and the glassy carbon electrode (BGCE) in step S1 of Example 3 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The working electrode was immersed in a 0.1 mM RF solution (the solvent was 0.2 M PBS with a pH of 7) and stirred for 90 min (pre-enrichment treatment). Then, the DPV detection signals were compared. The results are shown in FIG. Figure 6 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 3 for 0.1 mM RF reaches 1.19×10 -3 A, BGCE electrode signal (2.91×10 -4 A) Compared with the above results, the intensity is increased by an order of magnitude, indicating that the coating of electrode modification materials significantly enhances the detection sensitivity of the electrode to riboflavin.

[0088] Example 4

[0089] The preparation steps of the electrode for riboflavin detection are:

[0090] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0091] S2, adding 0.001 g of graphene oxide and 0.005 g of CeO2 nanoparticles into 0.001 L of ethanol solution (mass fraction 100%), and ultrasonicating for 30 min to make them dispersed evenly to obtain an electrode modification material;

[0092] S3. Take 8 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0093] The electrode prepared in Example 4 and the glassy carbon electrode (BGCE) in step S1 of Example 4 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The working electrode was immersed in a 5 μM RF solution (the solvent was 0.2 M PBS with a pH of 7) and stirred for 20 min (pre-enrichment treatment). Then, the DPV detection signals were compared. The results are shown in FIG. Figure 7 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 4 for 5 μM RF reaches 6.99×10 -4 A, BGCE electrode signal (2.91×10 -4 A) Compared with the results of Figure 2, it shows that the coating of electrode modification materials significantly enhances the detection sensitivity of the electrode to riboflavin.

[0094] Example 5

[0095] The preparation steps of the electrode for riboflavin detection are:

[0096] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0097] S2, adding 0.001g of graphene oxide, 0.005g of CeO2 nanoparticles and 5μL of Nafion solution (concentration of 5wt.%) into 0.001L of ethanol solution (mass fraction 80%), and ultrasonicating for 30min to make them dispersed evenly to obtain an electrode modification material;

[0098] S3. Take 8 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0099] The electrode prepared in Example 5 and the glassy carbon electrode (BGCE) in step S1 of Example 5 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The working electrode was immersed in a 5 μM RF solution (the solvent was 0.2 M PBS with a pH of 7) and stirred for 20 min (pre-enrichment treatment). Then, the DPV detection signals were compared. The results are shown in FIG. Figure 8 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 5 for 5 μM RF reaches 6.52×10 -4 A, BGCE electrode signal (2.91×10 -4 A) Compared with the above, coating electrode modification materials can significantly enhance the detection sensitivity of the electrode to riboflavin.

[0100] Example 6

[0101] The preparation steps of the electrode for riboflavin detection are:

[0102] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0103] S2, adding 0.001g of graphene oxide and 0.003g of CeO2 nanoparticles into 0.001L of ethanol solution (mass fraction 100%), and ultrasonicating for 30min to make them dispersed evenly, to obtain an electrode modification material;

[0104] S3. Take 8 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0105] The electrode prepared in Example 6 and the glassy carbon electrode (BGCE) in step S1 of Example 6 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The DPV detection signals of 0.1 mM RF solution (solvent was 0.2 M PBS at pH = 7) were compared. The results are shown in FIG. Fig. 9 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 6 for 0.1 mM RF reaches 7.23×10 -4 A, BGCE electrode signal (2.91×10 -4 A) Compared with the above, coating electrode modification materials can significantly enhance the detection sensitivity of the electrode to riboflavin.

[0106] Example 7

[0107] The preparation steps of the electrode for riboflavin detection are:

[0108] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0109] S2, adding 0.001g of graphene oxide and 0.005g of CeO2 nanoparticles into 0.001L of ethanol solution (mass fraction 100%), and ultrasonicating for 30min to make them dispersed evenly, to obtain an electrode modification material;

[0110] S3. Take 5 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0111] The electrode prepared in Example 7 and the glassy carbon electrode (BGCE) in step S1 of Example 7 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode to compare the DPV detection signals of a 0.1 mM RF solution (the solvent was 0.2 M PBS at pH = 7). The results are shown in FIG. Fig.10 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 7 for 0.1 mM RF reaches 6.03×10 -4 A, BGCE electrode signal (2.91×10 -4 A) Compared with the above, coating electrode modification materials can significantly enhance the detection sensitivity of the electrode to riboflavin.

[0112] Example 8

[0113] The preparation steps of the electrode for riboflavin detection are as follows: S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for standby use; S2. Add 0.001g of graphene oxide and 0.01g of CeO2 nanoparticles to 0.001L of ethanol solution (mass fraction 100%), and ultrasonicate for 30 minutes to disperse it evenly to obtain an electrode modification material; S3. Take 8μL of the electrode modification material, drop it on the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0114] The electrode prepared in Example 8 and the glassy carbon electrode (BGCE) in step S1 of Example 8 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode to compare the DPV detection signals of a 0.1 mM RF solution (the solvent was 0.1 M PBS at pH = 7). The results are shown in FIG. Fig.11 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 8 for 0.1 mM RF reaches 3.03×10 -4 A, BGCE electrode signal (2.91×10-4 A) Compared with the above, coating with modified materials can significantly enhance the detection sensitivity of the electrode to riboflavin.

[0115] Example 9

[0116] The preparation steps of the electrode for riboflavin detection are:

[0117] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0118] S2, adding 0.001 g of graphene oxide and 0.005 g of CeO2 nanoparticles into 0.001 L of ethanol solution (mass fraction 100%), and ultrasonicating for 30 min to make them dispersed evenly to obtain an electrode modification material;

[0119] S3. Take 8 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0120] The electrode prepared in Example 9 and the glassy carbon electrode (BGCE) in step S1 of Example 9 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The working electrode was immersed in a 0.1 mM RF solution (the solvent was 0.2 M PBS with a pH of 7) for 2 min (pre-enrichment treatment), and then the DPV detection signals were compared. The results are shown in FIG. Fig.12 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 9 to 0.1 mM RF reaches 7.5×10 -4 A, BGCE electrode signal (2.91×10 -4 A) Compared with the above, coating electrode modification materials can significantly enhance the detection sensitivity of the electrode to riboflavin.

[0121] The linear detection range of RF solution at different concentrations was 0.5 μM~75 μM (e.g. Fig.13 ), and studied the doping ions and the actual VB2 medicine. Example 9 can resist K + 、Na + , Vc, Gly (glycine) interference, the interference degree is less than 5% (such as Fig.14 ), the actual VB2 drug was dissolved and diluted to 53μM concentration with 0.2M PBS, and the results were as follows Fig.15 The detection peak value reached 6.23×10 - 4 A, The peak value corresponding to 53 μM in the linear fitting curve (5.99×10 -4Compared with A), the error is 4%, indicating that the modified electrode can be used for the detection of actual VB2 tablets. The electrode prepared in Example 9 of the present invention was subjected to CV and impedance tests in potassium ferrocyanide solution, and it was found that the redox peak current and electron transfer activity (such as Fig.16 , 17 ) is enhanced compared with BGCE, and the curves of Examples 1-8 and Example 10 are similar to Example 9.

[0122] Example 10

[0123] The preparation steps of the electrode for riboflavin detection are:

[0124] S1. Polish the glassy carbon electrode with alumina slurry on suede and lens paper until it is bright, then rinse it with deionized water and ethanol respectively. After cleaning, blow dry the surface with nitrogen for later use;

[0125] S2, adding 0.001 g of graphene oxide and 0.005 g of CeO2 nanoparticles into 0.001 L of aqueous solution, and performing ultrasonic treatment for 30 min to make them dispersed evenly, to obtain an electrode modification material;

[0126] S3. Take 8 μL of electrode modification material, drop it onto the surface of the glassy carbon electrode, blow dry, and obtain an electrode for riboflavin detection.

[0127] The electrode prepared in Example 10 and the glassy carbon electrode (BGCE) in step S1 of Example 10 were used as working electrodes, a platinum electrode was used as a counter electrode, and Ag / AgCl was used as a reference electrode. The working electrode was immersed in a 0.1 mM RF solution (the solvent was 0.2 M PBS with a pH of 7) for 2 min (pre-enrichment treatment), and then the DPV detection signals were compared. The results are shown in FIG. Fig.18 As shown in FIG. 1 , it can be found that the detection signal of the electrode coated with the electrode modification material in Example 10 for 0.1 mM RF reaches 7.15×10 -4 A, BGCE electrode signal (2.91×10 -4 A) Compared with the above, coating electrode modification materials can significantly enhance the detection sensitivity of the electrode to riboflavin.

[0128] Comparative Example 1

[0129] Compared with Example 7, the difference is that graphene oxide is not added, and the drop coating amount is increased to 8 μL.

[0130] The same test method as in Example 7 was used, and the results were as follows Fig.19 As shown in the figure, it can be found that the signal intensity has not been significantly enhanced, indicating that the cerium dioxide nanoparticles not composited with graphene oxide have no significant effect on the sensitivity of riboflavin detection.

[0131] Comparative Example 2

[0132] Compared with Example 2, the only difference is that the pH of the PBS solution is 8.

[0133] The electrodes prepared in Comparative Example 2 and Example 2 were compared with the DPV detection signals of 5 μM RF solution using the test method in Example 2. The results are as follows: Fig. 20 As shown in the figure, it can be found that when the pH of the PBS solution is 8, it affects the detection peak shape, which is not conducive to the detection of riboflavin by the electrode.

[0134] Comparative Example 3

[0135] Compared with Example 8, the difference is that no cerium dioxide nanoparticles are added.

[0136] The electrodes prepared in Comparative Example 3 and Example 8 were compared with the DPV detection signals of 0.1 mM RF solution using the test method in Example 8. The results are as follows: Fig.21 As shown, it can be found that the detection sensitivity of graphene oxide without complexing with cerium dioxide nanoparticles to riboflavin is not as high as that of complexing with cerium dioxide nanoparticles.

[0137] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. Application of an electrode modification material in riboflavin detection, characterized in that: The effective components of the electrode modification material include graphene oxide and CeO2 nanoparticles; the mass ratio of the graphene oxide to the CeO2 nanoparticles is 0.5-3:3-15; the CeO2 nanoparticles are spherical nanoparticles with a particle size of 20nm-50nm; The riboflavin in the sample to be tested is electrochemically detected using a three-electrode system; the pH value of the sample to be tested is 5-7; Before the electrochemical detection of riboflavin in the sample by the three-electrode system, the working electrode modified with the electrode modification material is pre-enriched in the sample to be tested for 0 to 90 minutes, and the pre-enrichment time is not zero.

2. The use according to claim 1, characterized in that The electrode modification material also includes Nafion.

3. A method for electrochemically detecting riboflavin in a sample, characterized in that the steps include: Using ethanol solution or water as solvent and electrode modification material as effective component to prepare a mixed solution; Using the mixed solution to drop-coat the surface of the working electrode, removing the solvent, and modifying the working electrode to obtain an electrode for riboflavin detection; A three-electrode system was used to electrochemically detect riboflavin in the sample to be tested; The effective components of the electrode modification material include graphene oxide and CeO2 nanoparticles; the mass ratio of the graphene oxide to the CeO2 nanoparticles is 0.5-3:3-15; and the CeO2 nanoparticles are spherical nanoparticles with a particle size of 20nm-50nm.

4. The method according to claim 3, characterized in that Before the electrochemical detection of riboflavin in the sample using the three-electrode system, the working electrode modified with the electrode modification material is pre-enriched in the sample to be tested for 0-90 minutes, and the pre-enrichment time is not 0; the pH value of the sample to be tested is 5-7.

5. The method according to claim 3, characterized in that: The working electrode is a glassy carbon electrode; the concentration of the ethanol solution is 80% to 100%, the concentration of graphene oxide in the mixed solution is 0.5-3 g / L, the concentration of CeO2 nanoparticles is 3-15 g / L, and the CeO2 nanoparticles are spherical nanoparticles with a particle size of 20 nm to 50 nm; the drop coating amount of the electrode modification material is 0.25 to 0.51 μL / mm 2 .

6. The method according to claim 3, characterized in that The mixed solution also includes a Nafion solution.

7. The method according to claim 6, characterized in that The concentration of the Nafion solution is 5 wt.%; the amount of the Nafion solution added to the mixed solution is 0-5 μL / L, and is not 0.

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