Quaternary ammonium salt modification-based MXene non-enzymatic uric acid electrochemical sensor, method and application

Abstract

The invention discloses a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt modified MXene, a method and application, and belongs to the technical field of sensors. The preparation method comprises the following steps: preparing an MXene material through an etching method; the preparation method comprises the following steps: modifying an MXene material by adopting quaternary ammonium salt to obtain a modified MXene material; a working electrode is modified with the modified MXene material, a reference electrode and a counter electrode are combined to form a three-electrode system, and the non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt modified MXene is obtained. The prepared non-enzymatic uric acid electrochemical sensor is excellent in performance, high in sensitivity and low in detection limit; the linear range is wide and covers the human blood uric acid concentration range; the stability is good, and the influence by temperature and pH is avoided; the biological compatibility is good, the antibacterial property is good, and the toxicity is low. The sensor can realize rapid and quantitative detection of human blood uric acid concentration, has excellent detection performance, and has no obvious difference with the detection result of a large biochemical analysis instrument.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene (MXene) material, a method and an application thereof. Background Art

[0002] Hyperuricemia is a common chronic metabolic disease, and its typical pathological feature is a blood uric acid concentration higher than 360μmol / L (female) or 420μmol / L (male). The latest data show that the prevalence of hyperuricemia among adult residents in my country is as high as 14.0%, of which the prevalence rates are 24.5% and 3.6% in males and females respectively. Young men aged 18-39 and elderly men over 70 are the peak populations for the disease. Hyperuricemia is very harmful and can induce rheumatic arthritis, kidney stones, uric acid nephropathy, etc. Therefore, rapid and accurate detection of blood uric acid concentration is conducive to the prevention, control, diagnosis and daily management of hyperuricemia.

[0003] Existing uric acid electrochemical sensors can be divided into two categories: enzymatic and non-enzymatic. Enzymatic electrochemical sensors usually use urate oxidase as a biorecognition element. Urate oxidase can specifically oxidize uric acid into allantoin, hydrogen peroxide and carbon dioxide. By measuring the value of the oxidation or reduction current of hydrogen peroxide, the uric acid concentration can be indirectly measured. Non-enzymatic electrochemical sensors do not rely on the catalytic action of biological enzymes, but are based on the direct electrochemical reaction between electrode materials and uric acid. Uric acid molecules can directly undergo oxidation reactions on the electrode surface and generate current signals at the same time. By measuring the value of the oxidation current, the uric acid concentration can be directly measured.

[0004] Currently, the uric acid detection sensors on the market are all based on the above two principles, but these sensors still have the following problems: (1) Susceptible to interference - other electrochemically active small molecules in the blood, such as ascorbic acid, acetaminophen, adrenaline, etc., will produce signals similar to uric acid on the sensor, thereby interfering with the detection of blood uric acid; (2) Narrow detection range and low detection limit - the current blood uric acid detection lower and upper limits of products on the market are approximately 180mmol / L and 1100mmol / L, respectively, and are unable to detect lower concentrations of blood uric acid; (3) High cost - whether it is an enzyme or non-enzyme sensor, it needs to use uricase or ascorbate to improve the specificity of the sensor. However, the cost of biological enzymes is high, which is also an important reason why the price of uric acid test strips is higher than that of glucose test strips.

[0005] For example, the patent document with application publication number CN115343340 A discloses a method of treating graphite electrodes with plasma. By treating graphite electrodes with plasma, the electrochemical selectivity of uric acid can be improved. The graphite electrode can resist the interference of ascorbic acid, dopamine and other substances in the blood with uric acid detection. However, the uric acid detection potential of this electrode is relatively high, and other interfering substances in the blood, such as acetaminophen, xanthine, hypoxanthine, adrenaline, etc., will still interfere with uric acid detection.

[0006] For example, the patent document with application publication number CN114235925 A discloses a method for preparing an anti-interference electrochemical uric acid test paper, which shields the interference of ascorbic acid by adding ascorbic acid oxidase, and uses uric acid oxidase and an electron mediator to improve the sensitivity and selectivity of uric acid detection. However, ascorbic acid oxidase is expensive, the addition of the enzyme will reduce the activity of the electrode, and the shelf life is short. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects in the prior art and provide a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt modified MXene, method and application. The present invention prepares MXene materials by etching and quaternary ammonium salt modification. The quaternary ammonium salt modified MXene materials have uniform size, good dispersibility, high stability and excellent electrical properties; a working electrode, a reference electrode and a counter electrode are prepared on a flexible film to construct a three-electrode system; the modified MXene material is modified on the working electrode to prepare a non-enzymatic uric acid electrochemical sensor. The sensor has the characteristics of low cost, simple preparation process, good selection and wide detection range, and can realize rapid and quantitative detection of human blood uric acid concentration. Taking fingertip blood uric acid detection as an example, the sensor shows good linearity in response to uric acid in the blood, and the detection results are not significantly different from those of large-scale biochemical analysis instruments.

[0008] The specific technical solutions adopted by the present invention are as follows:

[0009] The present invention provides a method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene, which is as follows:

[0010] S1: MXene material is prepared by etching method;

[0011] S2: modifying the MXene material with a quaternary ammonium salt to obtain a modified MXene material;

[0012] S3: The modified MXene material is modified on the working electrode, combined with a reference electrode and a counter electrode to form a three-electrode system, and a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene is obtained.

[0013] Preferably, the S1 is as follows:

[0014] S11: etching the MXene precursor material MAX with an etchant under heating conditions; the solvent of the etchant is an organic solvent;

[0015] S12: The product obtained in S11 is washed and dispersed with an acidic aqueous solution to obtain a MXene material.

[0016] Furthermore, in S11, the heating temperature is 30-200°C and the heating time is 2-120h; the etchant is one of divalent cupric salt, cuprous salt, elemental iodine, trivalent iron salt, mercurous salt and hydrogen fluoride, and the precursor material MAX is V 2 AlC, T 2 AlN、Ti 3 AlC 2 、V 3 AlC 2 、 3 AlC 2 、 4 AlN 3 、V 4 AlC 3 , Nb 4 AlC 3 、 4 AlC 3 The organic solvent is one of acetone, acetonitrile, n-hexane and dichloromethane, and the mixed molar ratio of the precursor material MAX to the etchant is 1: (1-4);

[0017] In S12, the acidic aqueous solution is one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, perchloric acid, and hydrofluoric acid aqueous solutions, and the concentration of the acidic aqueous solution is 0.01-10 mol / L; the washing method is stirring or shaking; and the dispersion method is hand shaking or ultrasound.

[0018] Preferably, the S2 is as follows:

[0019] S21: chemically modifying the MXene material obtained in S1 using a quaternary ammonium salt in an alkaline solution under heating conditions;

[0020] S22: washing the product obtained in S21 with water;

[0021] S23: Dry the product obtained in S22 to obtain a modified MXene material.

[0022] Further, in S21, the heating temperature is 30-120°C; the reaction time is 2-6h; the quaternary ammonium salt is tetraoctylammonium bromide, tetra-n-octylammonium bromide, tetraethylammonium chloride, tetrapropylammonium chloride, bis(triphenylphosphine)ammonium chloride, (dodecyl)methylammonium chloride, tetramethylammonium chloride, tetramethylammonium chloride, tetrabutylammonium perchlorate, cerium ammonium nitrate, tetraethylammonium bromide, phenyltrimethylammonium chloride, methyltrioctylammonium chloride, didodecyldimethylammonium bromide, tetrabutylborane One of ammonium hydride, tetraethylammonium perchlorate, tetra-n-hexylammonium bromide, tetrabutylammonium fluoride, tetra-n-butylammonium fluoride, tetrabutylammonium acetate, n-tetrahexylammonium chloride, polydiallyldimethylammonium chloride, didodecyldimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyldimethylbenzylammonium chloride, tetra(dodecyl)ammonium bromide, tetra(dodecyl)ammonium chloride and tetrabutylammonium chloride; the mixing mass ratio of the quaternary ammonium salt to the MXene material is 1:(0.1-10);

[0023] In S22, the washing method is stirring or shaking, and the washing is performed until the pH of the washing liquid is 7;

[0024] In S23, the drying method is one of drying, air-drying and freeze-drying.

[0025] Preferably, S3 is as follows:

[0026] S31: Processing a working electrode, a reference electrode and a counter electrode on the surface of a flexible substrate membrane to form a three-electrode system;

[0027] S32: The modified MXene material and the stabilization layer obtained in S2 are sequentially modified on the surface of the working electrode.

[0028] Further, in S31, the flexible substrate film is a polymer film, and the material is one of polyurethane, polyimide, polydimethylsiloxane, polyvinyl alcohol, polyethylene terephthalate and polyethylene naphthalate; the materials of the working electrode and the counter electrode are one of carbon paste, graphite, carbon nanotubes, graphene, gold and platinum, and the processing method includes one of screen printing, printing, laser pyrolysis and magnetron sputtering; the reference electrode material is silver / silver chloride, and the processing method includes screen printing or printing;

[0029] In the S32, the modification method includes one of drip coating, spin coating and spray coating; the concentration of the modified MXene material is 0.01-100 mg / L; and the stabilization layer material is a 0.1%-5% mass fraction of perfluorosulfonic acid or chitosan solution.

[0030] In a second aspect, the present invention provides a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene obtained by any preparation method described in the first aspect.

[0031] In a third aspect, the present invention provides an application of a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene described in the second aspect in the determination of blood uric acid concentration.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) A MXene material with significant catalytic activity for uric acid was obtained by etching and quaternary ammonium salt modification. (2) The quaternary ammonium MXene material was modified on the working electrode surface of a homemade three-electrode system to prepare a non-enzymatic uric acid electrochemical sensor. (3) The sensor is low-cost, simple to operate, and easy to mass produce. It has excellent performance and can reduce the uric acid detection potential, eliminate interference from other substances, and achieve accurate and rapid detection of uric acid in the blood. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 (a) is the scanning electron microscope (SEM) image of MAX; (b) is the SEM image of MXene material; (c) is the SEM image of quaternized MXene material.

[0035] Figure 2 X-ray diffraction (XRD) patterns of MAX, MXene, and quaternized MXene.

[0036] Figure 3 X-ray photoelectron spectroscopy (XPS) diagrams of MAX, MXene, and quaternized MXene.

[0037] Figure 4 For the quaternized MXene electrochemical sensor and the commercial screen-printed gold electrode to 5 mM K 3 Fe(CN) 6 (a), Ru(NH 3 )Cl 6 (b) and 0.5 mM FcMeOH (c) cyclic voltammograms.

[0038] Figure 5 The differential pulse voltammetry curves (a) and linear relationship curves (b) of the quaternized MXene electrochemical sensor for different uric acid solutions.

[0039] Figure 6 Cyclic voltammograms of the quaternized MXene electrochemical sensor for uric acid detection (a) and selectivity for dopamine (b) and ascorbic acid (c). DETAILED DESCRIPTION

[0040] The present invention is further described and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0041] The present invention prepares MXene material by oxidative etching and quaternary ammonium salt modification, prepares working electrode, reference electrode and counter electrode on flexible film, and modifies the modified MXene material on the working electrode to prepare non-enzymatic uric acid electrochemical sensor. The sensor has the characteristics of low cost, simple preparation process, good selection and wide detection range, can realize rapid and quantitative detection of human blood uric acid concentration, and is expected to be applied in the prevention, diagnosis and daily management of hyperuricemia.

[0042] The preparation method of the non-enzymatic uric acid electrochemical sensor of the present invention is as follows:

[0043] S1: MXene material was prepared by etching method.

[0044] As a preferred embodiment of the present invention, the steps are as follows:

[0045] S11: Under heating conditions, the MXene precursor material MAX is etched with an etchant, wherein the etchant needs to be dissolved into a solution before use, and the solvent is an organic solvent.

[0046] In actual use, the heating temperature is 30-200°C, the heating time is 2-120h (preferably 96h); the etchant is one of divalent cupric salt, cuprous salt, elemental iodine, trivalent iron salt, mercurous salt and hydrogen fluoride; the precursor material MAX is V 2 AlC, T 2 AlN、Ti 3 AlC 2 、V 3 AlC 2 、 3 AlC 2 、 4 AlN 3 、V 4 AlC 3 , Nb 4 AlC 3 、 4 AlC 3 The organic solvent is one of acetone, acetonitrile, n-hexane and dichloromethane; the mixed molar ratio of the precursor material MAX and the etchant is 1: (1-4).

[0047] S12: The product obtained in S11 is washed and dispersed with an acidic aqueous solution to obtain a MXene material.

[0048] In actual use, the acidic aqueous solution is one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, perchloric acid, and hydrofluoric acid aqueous solutions, and the concentration of the acidic aqueous solution is 0.01-10 mol / L; the washing method is stirring or shaking; and the dispersion method is hand shaking or ultrasound.

[0049] S2: Modifying the MXene material with a quaternary ammonium salt to obtain a modified MXene material.

[0050] As a preferred embodiment of the present invention, the steps are as follows:

[0051] S21: Under heating conditions, in an alkaline solution, chemically modifying the MXene material obtained in S1 using a quaternary ammonium salt.

[0052] In actual use, the heating temperature is 30-120°C, and the heating reaction time is 2-120h; the quaternary ammonium salt is tetraoctylammonium bromide, tetra-n-octylammonium bromide, tetraethylammonium chloride, tetrapropylammonium chloride, bis(triphenylphosphine)ammonium chloride, (dodecyl)methylammonium chloride, tetramethylammonium chloride, tetramethylammonium chloride, tetrabutylammonium perchlorate, cerium ammonium nitrate, tetraethylammonium bromide, phenyltrimethylammonium chloride, methyltrioctylammonium chloride, didodecyldimethylammonium bromide, tetrabutylborohydride One of ammonium chloride, tetraethylammonium perchlorate, tetra-n-hexylammonium bromide, tetrabutylammonium fluoride, tetra-n-butylammonium fluoride, tetrabutylammonium acetate, n-tetrahexylammonium chloride, polydiallyldimethylammonium chloride, didodecyldimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyldimethylbenzylammonium chloride, tetra(dodecyl)ammonium bromide, tetra(dodecyl)ammonium chloride and tetrabutylammonium chloride; the mixing mass ratio of the quaternary ammonium salt to the MXene material is 1:(0.1-10).

[0053] S22: Wash the product obtained in S21 with water (preferably deionized water).

[0054] In actual use, the washing method is stirring or shaking, and washing is performed until the pH of the washing liquid is 7.

[0055] S23: Dry the product obtained in S22 to obtain a modified MXene material.

[0056] In actual use, the drying method is one of oven drying, air drying and freeze drying.

[0057] S3: The modified MXene material obtained in S2 is modified on the working electrode, combined with the reference electrode and the counter electrode to form a three-electrode system, and a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene is obtained.

[0058] As a preferred embodiment of the present invention, the steps are as follows:

[0059] S31: Processing a working electrode, a reference electrode and a counter electrode on the surface of a flexible substrate membrane to form a three-electrode system.

[0060] In actual use, the flexible base film is a polymer film, and the material is one of polyurethane, polyimide, polydimethylsiloxane, polyvinyl alcohol, polyethylene terephthalate and polyethylene naphthalate, and the thickness is generally 1-3mm; the materials of the working electrode and the counter electrode are one of carbon paste, graphite, carbon nanotubes, graphene, gold and platinum, and the processing methods include screen printing, printing, laser pyrolysis and magnetron sputtering; the reference electrode material is silver / silver chloride, and the processing methods include screen printing or printing.

[0061] S32: The modified MXene material and the stabilization layer obtained in S2 are sequentially modified on the surface of the working electrode.

[0062] In actual use, the modification method includes one of drip coating, spin coating and spray coating; the concentration of the modified MXene material is 0.01-100 mg / L; the stabilization layer material is a 0.1%-5% mass concentration perfluorosulfonic acid (Nafion) or chitosan (CHI) solution, wherein the solvent of perfluorosulfonic acid is generally ethanol, methanol and acetone, and the solvent of chitosan is generally 3% to 5% mass concentration acetic acid solution.

[0063] The following examples will specifically illustrate the preparation method and application of the non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene of the present invention.

[0064] Example 1

[0065] In this embodiment, MXene material was prepared by etching method, and quaternary ammonium salt modified MXene material was further obtained. The details are as follows:

[0066] 1) 0.1 g of MAX material (Ti in this example) 3 AlC 2 ) and 0.5 g of etching agent (I 2 ) were added to 10 mL of an organic solution (anhydrous acetonitrile in this embodiment) in sequence, reacted at 100° C. for 96 h in a polytetrafluoroethylene-lined reactor, washed and centrifuged to obtain a solid, dispersed in a 1 M sulfuric acid solution, shaken manually, and then dried at 100° C.

[0067] 2) The MXene material obtained above was redispersed in a sodium hydroxide solution containing 10% by mass, 0.5 g of a quaternary ammonium salt (hexadecyltrimethylammonium chloride in this embodiment) was added, and the mixture was reacted at 60° C. for 3 h. The mixture was washed, centrifuged, and dried to obtain a solid powder of the quaternary ammonium salt-modified MXene material.

[0068] 3) After the preparation is completed, the morphology and performance of the above-mentioned MAX, MXene and quaternary ammonium salt modified MXene are first characterized. The test analysis results are as follows Figures 1 to 3 As shown. Figure 1 a is the scanning electron microscope image of MAX. From the image, we can see that the surface of the material is relatively flat and the layers are relatively close. After iodine etching, the scanning electron microscope image of MXene shows that the material layers become loose, showing the accordion structure of MXene material ( Figure 1 b) If Figure 1 As shown in c, after being modified by quaternary ammonium salt, MXene still retains the layered structure of MXene, but the interlayer is smaller than Figure 1 b becomes tight. Figure 2 As shown, from the XRD patterns of MAX, MXene and quaternary ammonium salt modified MXene, it can be seen that the 004 characteristic peak of MAX is significantly weakened after iodine etching, and the 002 peak shifts to the left. According to the Bragg equation, the interlayer spacing of the material becomes larger. After modification with quaternary ammonium salt, the 002 peak shifts to the right, and the interlayer spacing of the material becomes smaller but is still higher than that of the MAX material. Figure 3 The XPS spectra of MAX, MXene and quaternary ammonium salt modified MXene are shown in Figure 2. 3d The signal proves the successful etching of MXene materials.

[0069] Example 2

[0070] 1) 0.5 g of MAX material (Ti in this example) 3 AlC 2 ) and 1 g of a low oxidation potential oxidant (iodine in this embodiment) are mixed in 20 mL of an organic solution (toluene in this embodiment), reacted at 100° C. for 48 h in a polytetrafluoroethylene-lined reactor, centrifuged and filtered to obtain a solid, which was dispersed in a 1 M dilute hydrochloric acid solution and dried at 80° C.

[0071] 2) The obtained solid was dissolved in a 10% sodium hydroxide solution, and then 1 g of a quaternary ammonium salt modifier (tetramethylammonium chloride in this embodiment) was added and reacted at 80° C. for 3 h. After washing, centrifugation and drying, a solid powder of a quaternary ammonium salt-modified MXene material similar to that in Example 1 was obtained.

[0072] 3) 1 g of quaternary ammonium salt-modified MXene material was dispersed in 100 mL of deionized water, and then 30 μL of the solution was drop-coated on a flexible gold electrode (prepared by sputtering in this embodiment) to prepare a working electrode. The counter electrode was a gold electrode prepared by the same method, and the reference electrode was coated with Ag / AgCl slurry and dried. A solution with a mass fraction of 1% Nafion was coated on the working electrode and dried to obtain a quaternized MXene uric acid electrochemical sensor.

[0073] Prepare 5 mM K using sodium hydrogen phosphate / sodium dihydrogen phosphate (PB) buffer. 3Fe(CN) 6 、Ru(NH 3 )Cl 6 The cyclic voltammetry performance of the quaternized MXene electrochemical sensor prepared above was tested with 0.5 mM FcMeOH. The results are shown in Figure 4 As shown in the figure, the sensor is sensitive to negatively charged K 3 Fe(CN) 6 The corresponding current is much higher than that of the gold electrode. 3 )Cl 6 The responses of and FcMeOH are similar to those of the gold electrode.

[0074] Example 3

[0075] 1) Taking the detection of uric acid in PB solution as an example, the detection performance of the quaternized MXene electrochemical sensor for uric acid in Example 2 was tested: Differential pulse voltammetry tests were performed on the sensor for uric acid solutions of different concentrations (0, 100, 200, 300, 400, 500 μM). The results are shown in Figure 2. Figure 5 As shown in the figure, it can be seen that the oxidation potential of uric acid is as low as 0.08V. At the same time, the uric acid concentration and the current show a good linear relationship, and the correlation coefficient reaches 0.9954.

[0076] 2) Verify the selectivity of the sensor by adding different small molecule interfering substances: Since uric acid (UA), ascorbic acid (AA) and dopamine (DA) have similar oxidation potentials, it is difficult to distinguish them by direct electrochemical methods. Therefore, 500μM ascorbic acid solution and 100μM dopamine solution were used as examples to compare with 500μM uric acid solution to evaluate the selectivity of the material by line sweep voltammetry. Figure 6 As shown, except for uric acid, other substances have no obvious oxidation current, which proves its good electrochemical detection selectivity.

[0077] Example 4

[0078] Taking actual blood samples as an example, the accuracy of the quaternized MXene electrochemical sensor in Example 2 in detecting uric acid in actual samples was verified by comparison with the standard uricase-hydrogen peroxide method, and the obtained test value results and the results obtained by the standard method are shown in Table 1. The standard deviation of the test results compared with the standard method does not exceed 5%, which has good accuracy.

[0079] Table 1 Uric acid blood sample accuracy test

[0080]

[0081]

[0082] The non-enzymatic uric acid electrochemical sensor prepared by the present invention has excellent performance: high sensitivity, low detection limit; wide linear range, covering the human blood uric acid concentration range; good stability, not affected by temperature and pH; good biocompatibility, good antibacterial performance, and low toxicity. The sensor can realize rapid and quantitative detection of human blood uric acid concentration, with excellent detection performance, and no significant difference from the detection results of large-scale biochemical analysis instruments.

[0083] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene, characterized in that: The details are as follows: S1: MXene material is prepared by etching method; S2: modifying the MXene material with a quaternary ammonium salt to obtain a modified MXene material; S3: The modified MXene material is modified on the working electrode, combined with a reference electrode and a counter electrode to form a three-electrode system, and a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene is obtained.

2. The method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene according to claim 1, characterized in that: The S1 is specifically as follows: S11: etching the MXene precursor material MAX with an etchant under heating conditions; the solvent of the etchant is an organic solvent; S12: Wash and disperse the product obtained in S11 with an acidic aqueous solution to obtain a MXene material.

3. The method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene according to claim 2, characterized in that: In the S11, the heating temperature is 30-200°C and the heating time is 2-120h; the etchant is one of divalent cupric salt, cuprous salt, elemental iodine, trivalent iron salt, mercurous salt and hydrogen fluoride; the precursor material MAX is one of V2AlC, T2AlN, Ti3AlC2, V3AlC2, Ta3AlC2, Ta4AlN3, V4AlC3, Nb4AlC3 and Ta4AlC3; the organic solvent is one of acetone, acetonitrile, n-hexane and dichloromethane; the mixed molar ratio of the precursor material MAX and the etchant is 1:(1-4); In S12, the acidic aqueous solution is one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, perchloric acid, and hydrofluoric acid aqueous solutions, and the concentration of the acidic aqueous solution is 0.01-10 mol / L; the washing method is stirring or shaking; and the dispersion method is hand shaking or ultrasound.

4. The method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene according to claim 1, characterized in that: The S2 is specifically as follows: S21: chemically modifying the MXene material obtained in S1 using a quaternary ammonium salt in an alkaline solution under heating conditions; S22: washing the product obtained in S21 with water; S23: drying the product obtained in S22 to obtain a modified MXene material.

5. The method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene according to claim 4, characterized in that: In the S21, the heating temperature is 30-120°C; the reaction time is 2-6h; the quaternary ammonium salt is tetraoctylammonium bromide, tetra-n-octylammonium bromide, tetraethylammonium chloride, tetrapropylammonium chloride, bis(triphenylphosphine)ammonium chloride, (dodecyl)methylammonium chloride, tetramethylammonium chloride, tetramethylammonium chloride, tetrabutylammonium perchlorate, cerium ammonium nitrate, tetraethylammonium bromide, phenyltrimethylammonium chloride, methyltrioctylammonium chloride, didodecyldimethylammonium bromide, tetrabutylammonium borohydride , one of tetraethylammonium perchlorate, tetra-n-hexylammonium bromide, tetrabutylammonium fluoride, tetra-n-butylammonium fluoride, tetrabutylammonium acetate, n-tetrahexylammonium chloride, polydiallyldimethylammonium chloride, didodecyldimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyldimethylbenzylammonium chloride, tetra(dodecyl)ammonium bromide, tetra(dodecyl)ammonium chloride and tetrabutylammonium chloride; the mixing mass ratio of the quaternary ammonium salt to the MXene material is 1:(0.1-10); In S22, the washing method is stirring or shaking, and the washing is performed until the pH of the washing liquid is 7; In S23, the drying method is one of drying, air-drying and freeze-drying.

6. The method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene according to claim 1, characterized in that: The S3 is as follows: S31: Processing a working electrode, a reference electrode and a counter electrode on the surface of a flexible substrate membrane to form a three-electrode system; S32: The modified MXene material and the stabilization layer obtained in S2 are sequentially modified on the surface of the working electrode.

7. The method for preparing a non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene according to claim 6, characterized in that: In S31, the flexible substrate film is a polymer film, and the material is one of polyurethane, polyimide, polydimethylsiloxane, polyvinyl alcohol, polyethylene terephthalate and polyethylene naphthalate; the materials of the working electrode and the counter electrode are one of carbon paste, graphite, carbon nanotubes, graphene, gold and platinum, and the processing method includes one of screen printing, printing, laser pyrolysis and magnetron sputtering; the reference electrode material is silver / silver chloride, and the processing method includes screen printing or printing; In the S32, the modification method includes one of drip coating, spin coating and spray coating; the concentration of the modified MXene material is 0.01-100 mg / L; and the stabilization layer material is a 0.1%-5% mass fraction of perfluorosulfonic acid or chitosan solution.

8. A non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene obtained by the preparation method according to any one of claims 1 to 7.

9. An application of the non-enzymatic uric acid electrochemical sensor based on quaternary ammonium salt-modified MXene as claimed in claim 8 in the determination of blood uric acid concentration.

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