Preparation method of flexible electrochemical sensor based on rapid detection of trimethylamine in human urine

Abstract

The invention discloses a preparation method of a flexible electrochemical sensor for rapidly detecting trimethylamine in human urine, and belongs to the field of electrochemical sensors. In order to solve the problems that an existing electrochemical sensor for detecting trimethylamine in urine is high in cost, large in device size and large in needed reagent dosage, the invention provides a flexible electrochemical sensor for rapidly detecting trimethylamine in human urine, and the flexible electrochemical sensor comprises a heating electrode layer and a three-electrode layer which are sequentially stacked from bottom to top, and a tungsten trioxide / polyaniline (WO3 / PANI) composite material is modified on the working electrode of the three-electrode layer. The preparation method comprises the following steps: 1, preparing a nano material tungsten trioxide; 2, preparing an organic sensitive material polymer polyaniline; 3, preparation of a WO3 / PANI composite material; 4, preparing the flexible electrochemical sensor; 5, modifying a working electrode; the electrochemical sensor prepared by the invention can be used for trace, rapid and accurate detection of trimethylamine concentration in human urine.

Description

Technical Field

[0001] The invention belongs to the field of flexible electrochemical sensors, and in particular relates to a method for preparing a flexible electrochemical sensor based on rapid detection of trimethylamine in human urine. Background Art

[0002] As an important metabolite of human body fluid circulation, the metabolic process of urine involves the coordinated action of multiple organs including the urinary system. For example, trimethylamine in urine is an important basis for diagnosing chronic kidney disease. At present, the main methods for detecting trimethylamine in human urine include liquid chromatography-mass spectrometry (LC-MS), colorimetry, immunofluorescence, ion chromatography (IC), nuclear magnetic resonance (NMR), electrochemical molecular imprinting (MIP), etc. Each of the above methods for detecting urine trimethylamine levels has its own advantages and disadvantages. For example, liquid chromatography-mass spectrometry is an analytical chemistry technology that combines the material separation ability of liquid chromatography with the mass analysis ability of mass spectrometry. It has the advantages of high sensitivity, good specificity, and rapid operation, but high cost; colorimetry has the advantages of good selectivity and easy carrying, but low precision; immunofluorescence has high detection accuracy, but the required reagents and instruments are relatively expensive and the detection takes a long time; ion chromatography has the advantages of rapid detection, high sensitivity, and good stability, but the test results are easily affected by impurities; nuclear magnetic resonance can accurately study the structure and morphology of substances, and has the advantages of rapid detection and high accuracy, but the cost of instruments and equipment is high; electrochemical analysis has the advantages of low cost, high sensitivity, and high ease of operation.

[0003] There are two types of existing electrochemical sensors for the determination of trimethylamine in urine. One is an electrochemical detection system with an electrolytic cell, in which electrodes are placed in an electrolytic cell filled with a test solution to detect trimethylamine. However, this detection system is large in size and cannot be used in an integrated manner, and requires many reagents. It is usually used for the detection of trimethylamine in urine in a laboratory environment. The other is an electrochemical sensor prepared using screen printing technology, in which the electrochemical molecular imprinting method has the advantages of good selectivity and high sensitivity, but the material preparation is cumbersome and the cost is high. Although this sensor is small in size and easy to carry and store, it has the problems of being fragile and not very flexible and requiring high preparation conditions.

[0004] The present invention proposes a flexible electrochemical sensor for rapid detection of trimethylamine in urine and a preparation method thereof. The flexible electrochemical sensor has the characteristics of simple preparation, high sensitivity, strong anti-interference, flexibility, low cost, etc., and the constant temperature condition provided by the added heating electrode structure can also provide a stable and suitable detection environment for trimethylamine detection. A new rapid and accurate detection scheme is provided for the rapid detection of trimethylamine in urine for people at risk of chronic kidney disease. Summary of the invention

[0005] A method for preparing a flexible electrochemical sensor for rapid detection of trimethylamine in human urine, characterized in that the method for preparing a flexible electrochemical sensor for rapid detection of trimethylamine in human urine is implemented according to the following steps:

[0006] 1. Preparation of Nanomaterial Tungsten Trioxide

[0007] a. Weigh 2.05g sodium tungstate dihydrate crystals, 0.25g sodium sulfate crystals and 0.3g potassium sulfate crystals;

[0008] b. Dissolve all the weighed sodium tungstate dihydrate crystals, sodium sulfate crystals and potassium sulfate crystals in 40 mL of deionized water, and stir magnetically for 2 to 3 hours at room temperature to obtain solution A;

[0009] c. Place the solution A obtained in step b in a water bath at 45-60°C, slowly drop a 1 mol / L hydrochloric acid solution into the solution A at a uniform speed, and stir and mix at a uniform speed until the pH value of the mixed solution reaches 2-3, to obtain a solution B;

[0010] d. Transfer solution B to a stainless steel hydrothermal kettle with a volume of 100 mL, heat at 180°C for 18 to 24 hours, cool naturally to 25°C, transfer to a centrifuge, centrifuge at 4000r / min for 10 to 20 minutes, wash repeatedly with deionized water and anhydrous ethanol for 6 times, remove the supernatant, and obtain precipitate C; put precipitate C into a vacuum drying oven, vacuum dry at 60°C for 6 to 8 hours to obtain nano tungsten trioxide (WO3);

[0011] 2. Preparation of organic sensitive material polymer polyaniline

[0012] e. Take 10 mL of aniline solution, repeatedly distill and purify to obtain a high-purity aniline solution, take 5 mL of the high-purity aniline solution and add it to 500 mL of 1 mol / L dilute hydrochloric acid solution, stir magnetically for 40 to 60 minutes, and obtain a mixed solution D;

[0013] f. Weigh 11.4 g of ammonium persulfate (APS) and dissolve it in 50 mL of 1 mol / L hydrochloric acid solution to prepare an ammonium persulfate hydrochloric acid solution; slowly and uniformly add the ammonium persulfate hydrochloric acid solution to the mixed solution D at a rate of 5 drops / s using a long-necked funnel, and continue to stir and react in an ice-water bath for 2 to 3 hours to obtain a mixed solution E;

[0014] g. Filter the mixed solution E, and wash the filter cake obtained by filtration with 0.1 mol / L dilute hydrochloric acid solution, deionized water, and anhydrous ethanol three times respectively to obtain a precipitate F;

[0015] h. Dry the precipitate F under vacuum at 60° C. for 10 to 12 hours to obtain polyaniline (PANI);

[0016] 3. Preparation of WO3 / PANI composite materials

[0017] i. The tungsten trioxide prepared in step d and the polyaniline prepared in step h were dissolved in 10 mL of deionized water in a mass ratio of 1 to 2, and ultrasonically treated for 20 min to obtain a WO3 / PANI suspension. The suspension was vacuum dried at 60°C for 10 to 12 h to obtain a WO3 / PANI composite material. The suspension was placed in a mortar and mechanically ground for more than 20 to 24 h, and then 0.5 to 1 mL of pine alcohol was added and ground to a slurry G;

[0018] 4. Preparation of Flexible Electrochemical Sensors

[0019] The flexible electrochemical sensor device structure based on rapid detection of trimethylamine in human urine includes a heating electrode and three electrodes;

[0020] j. Take a piece of polyethylene naphthalate (PEN) insulating film and tear off the protective films on both sides. Take a dust-free cloth and dip it in an appropriate amount of anhydrous ethanol to wipe clean the flexible substrate (8) of the flexible electrochemical sensor of the present invention. Use a vacuum plasma cleaner to clean the surface of the flexible substrate (8). Place the cleaned flexible substrate (8) on the printing platform of a flexible microelectronic printer, install Ag conductive ink, use a dispensing needle with a diameter of 0.16 mm or 0.25 mm, use a dispensing process and set printing parameters to prepare a heating electrode pad (9) on the flexible substrate (8). After completion, place the substrate on an external heating table and dry it at 100° C. for 10 to 20 minutes to heat and cure.

[0021] k. Use a flexible microelectronic printer, replace the Cu conductive ink and load it into the printer, use a dispensing process to reset the parameters in the middle of the solidified flexible substrate (8) to prepare a heating electrode (10), and after preparation, put it into a drying oven and vacuum bake it at 150° C. for 20 to 30 minutes to anneal and shape it;

[0022] 1. Take a piece of PEN insulating film and tear off the protective films on both sides. Take a dust-free cloth and dip it in an appropriate amount of anhydrous ethanol to wipe it clean as the isolation layer (3) of the flexible electrochemical sensor of the present invention. Use a vacuum plasma cleaning machine to clean the surface of the isolation layer (3). Place the isolation layer (3) with the cleaned surface on the printing platform of a flexible microelectronic printer, replace it with Ag conductive ink, use a dispensing process and set printing parameters to print three electrode pads (4) and a reference electrode (5) on the isolation layer (3). After completion, place it on an external heating table and dry it at 100° C. for 15 to 20 minutes.

[0023] m. Use a flexible microelectronic printer, replace it with C conductive ink, and use a dispensing process to prepare a working electrode (7) and an auxiliary electrode (6) on the isolation layer (3). After completion, put them into a drying oven and vacuum bake them at 120° C. for 20 to 30 minutes to anneal and fix them;

[0024] n. The three electrode layers (1) and the heating electrode layer (2) of the sensor prepared in step k and step m are stacked from top to bottom in sequence, a proper amount of polyvinylidene fluoride (PVDF) is scraped on the bottom heating electrode layer (2), and the back of the three electrode layer (1) is pressed onto the front of the heating electrode layer (2), and the three electrode layers are placed in a drying oven, dried at 80° C. for 1 to 2 hours, and heated and cured;

[0025] 5. Modification of working electrode

[0026] o. The slurry G prepared in step i is dripped onto the working electrode (7) prepared in step m, and dried and solidified at room temperature to form a film to complete the modification of the working electrode, thereby completing the preparation of a flexible electrochemical sensor based on the rapid detection of trimethylamine in human urine.

[0027] The beneficial effects of the present invention are:

[0028] 1. The sensitive material prepared by the present invention is doped with inorganic metal oxide tungsten trioxide, which enhances the sensitivity of the electrochemical sensor;

[0029] 2. The organic polymer polyaniline is doped into the sensitive material prepared by the present invention, thereby enhancing the selectivity of the electrochemical sensor;

[0030] 3. The flexible electrochemical sensor for rapid detection of trimethylamine in urine prepared by the present invention uses flexible insulating materials as the sensor substrate and isolation layer, so that the sensor has the characteristics of flexibility, bendability and skin-friendly, and can be used in wearable devices to track and monitor human urine;

[0031] 4. The flexible electrochemical sensor for rapid detection of trimethylamine in urine prepared by the present invention adopts a high-precision dispensing process to prepare electrodes. Compared with the traditional silicon-based MEMS process, the process is simpler and the operation is more convenient. The width of the electrode prepared by the dispensing process can reach 0.20-0.25 mm, which can miniaturize the sensor and realize low-cost batch preparation;

[0032] 5. The working electrode of the flexible electrochemical sensor for rapid detection of trimethylamine in urine prepared by the present invention is modified with WO3 / PANI nanocomposite material, which can improve the selectivity of the sensor for trimethylamine in urine and realize accurate, trace and rapid detection of trimethylamine in urine. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the overall flow chart of the present invention;

[0034] Figure 2 is a scanning electron microscope image of polyaniline prepared in Example 1 of the present invention;

[0035] Figure 3 is a scanning electron microscope image of tungsten trioxide of Example 1 of the present invention;

[0036] Figure 4 is a scanning electron microscope image of the WO3 / PANI composite material of Example 1 of the present invention;

[0037] Figure 5 It is a schematic diagram of the overall structure of the flexible electrochemical sensor of the present invention;

[0038] Figure 6 is a top view of the heating electrode of the present invention;

[0039] Figure 7 is a top view of the three electrode layers of the present invention;

[0040] Figure 8 is a top view of the flexible electrochemical sensor of the present invention;

[0041] Fig. 9 This is a cyclic voltammetry curve diagram of the first example of the present invention for detecting trimethylamine in urine with different concentrations by cyclic voltammetry;

[0042] The markings in the figure are:

[0043] 1. Three-electrode layer, 2. Heating electrode layer, 3. Isolation layer, 4. Three-electrode pad, 5. Reference electrode, 6. Auxiliary electrode, 7. Working electrode, 8. Flexible substrate, 9. Heating electrode pad, 10. Heating electrode. Specific implementation methods

[0045] Specific implementation method 1: In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described below through specific embodiments and drawings.

[0046] 1. Preparation of Nanomaterial Tungsten Trioxide

[0047] a. Weigh 2.05g sodium tungstate dihydrate crystals, 0.25g sodium sulfate crystals and 0.3g potassium sulfate crystals;

[0048] b. Dissolve all the weighed sodium tungstate dihydrate crystals, sodium sulfate crystals and potassium sulfate crystals in 40 mL of deionized water, and stir magnetically for 3 hours at room temperature to obtain solution A;

[0049] c. Place solution A obtained in step b in a 60°C water bath, slowly and uniformly add 1 mol / L hydrochloric acid solution to solution A, and stir and mix at a uniform speed until the pH value of the mixed solution reaches 2.1, to obtain solution B;

[0050] d. Transfer solution B to a stainless steel hydrothermal kettle with a volume of 100 mL, heat at 180°C for 24 hours, cool to 25°C, transfer to a centrifuge, centrifuge at 4000r / min for 20 minutes, wash repeatedly with deionized water and anhydrous ethanol for 6 times, remove the supernatant, and obtain precipitate C; put precipitate C into a vacuum drying oven, vacuum dry at 60°C for 8 hours to obtain nano tungsten trioxide;

[0051] 2. Preparation of organic sensitive material polymer polyaniline

[0052] e. Take 10 mL of aniline solution, repeatedly distill and purify to obtain a high-purity aniline solution, take 5 mL of the high-purity aniline solution and add it to 500 mL of 1 mol / L dilute hydrochloric acid solution, stir magnetically for 60 min, and obtain a mixed solution D;

[0053] f. Weigh 11.4 g of ammonium persulfate (APS) and dissolve it in 50 mL of 1 mol / L hydrochloric acid solution to prepare an ammonium persulfate hydrochloric acid solution; slowly and uniformly add the ammonium persulfate hydrochloric acid solution to the mixed solution D at a rate of 5 drops / s using a long-necked funnel, and continue to stir and react in an ice-water bath for 3 hours to obtain a mixed solution E;

[0054] g. Filter the mixed solution E, and wash the filter cake obtained by filtration with 0.1 mol / L dilute hydrochloric acid solution, deionized water, and anhydrous ethanol three times respectively to obtain a precipitate F;

[0055] h. Dry the precipitate F under vacuum at 60° C. for 12 h to obtain polyaniline;

[0056] 3. Preparation of WO3 / PANI composite materials

[0057] i. Take 1 mg of the tungsten trioxide prepared in step d and the polyaniline prepared in step h in a mass ratio of 1:1 and dissolve them in 10 mL of deionized water, ultrasonically treat for 20 min to obtain a WO3 / PANI suspension, vacuum dry at 60°C for 12 h to obtain a WO3 / PANI composite material, put it in a mortar and grind it mechanically for 24 h, then add 0.5 mL of pine alcohol and grind it to a slurry G;

[0058] 4. Preparation of Flexible Electrochemical Sensors

[0059] The flexible electrochemical sensor device structure based on rapid detection of trimethylamine in human urine includes a heating electrode and three electrodes;

[0060] j. Take a piece of polyethylene naphthalate (PEN) insulating film and tear off the protective films on both sides, take a dust-free cloth dipped in an appropriate amount of anhydrous ethanol and wipe it clean to form a flexible substrate (8) of the flexible electrochemical sensor of the present invention, use a vacuum plasma cleaning machine to clean the surface of the flexible substrate (8), place the cleaned flexible substrate (8) on the printing platform of a flexible microelectronic printer, install Ag conductive ink, use a dispensing needle with a diameter of 0.16 mm, use a dispensing process and set printing parameters to prepare a heating electrode pad (9) on the flexible substrate (8), and after completion, place the substrate on an external heating table, dry it at 100° C. for 20 minutes, and heat and cure it;

[0061] k. Use a flexible microelectronic printer, replace the Cu conductive ink and load it into the printer, use a dispensing process to reset the parameters in the middle of the solidified flexible substrate (8) to prepare a heating electrode (10), and after preparation, put it into a drying oven and vacuum bake it at 150° C. for 30 minutes to anneal and shape it;

[0062] 1. Take a piece of PEN insulating film and tear off the protective films on both sides. Take a dust-free cloth and dip it in an appropriate amount of anhydrous ethanol to wipe it clean as the isolation layer (3) of the flexible electrochemical sensor of the present invention. Use a vacuum plasma cleaning machine to clean the surface of the isolation layer (3). Place the isolation layer (3) with the cleaned surface on the printing platform of a flexible microelectronic printer, replace it with Ag conductive ink, use a dispensing process and set printing parameters to print three electrode pads (4) and a reference electrode (5) on the isolation layer (3). After completion, place it on an external heating table and dry it at 100° C. for 20 minutes.

[0063] m. Use a flexible microelectronic printer, replace with C conductive ink, and use a dispensing process to prepare a working electrode (7) and an auxiliary electrode (6) on the isolation layer (3). After completion, put them into a drying oven and vacuum bake them at 120° C. for 30 minutes to anneal and fix them;

[0064] n. The three electrode layers (1) and the heating electrode layer (2) of the sensor prepared in step k and step m are stacked from top to bottom in sequence, a layer of polyvinylidene fluoride (PVDF) is scraped on the front of the bottom heating electrode layer (2), and the back of the three electrode layers (1) is pressed onto the front of the heating electrode layer (2), and the layers are placed in a drying oven, dried at 80° C. for 2 hours, and heated and cured;

[0065] 5. Modification of working electrode

[0066] o. The slurry G prepared in step i is drop-coated on the working electrode (7) prepared in step m, and dried at room temperature for 24 hours to solidify into a film to complete the modification of the working electrode, thereby completing the preparation of a flexible electrochemical sensor based on the rapid detection of trimethylamine in human urine.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. A person skilled in the art may modify or make equivalent substitutions for the technical solutions of the present invention without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A method for preparing a flexible electrochemical sensor for rapid detection of trimethylamine in human urine, characterized in that The preparation method of the flexible electrochemical sensor based on the rapid detection of trimethylamine in human urine is implemented by the following steps:

1. Preparation of Nanomaterial Tungsten Trioxide a. Weigh 2.05g sodium tungstate dihydrate crystals, 0.25g sodium sulfate crystals and 0.3g potassium sulfate crystals; b. Dissolve all the weighed sodium tungstate dihydrate crystals, sodium sulfate crystals and potassium sulfate crystals in 40 mL of deionized water, and stir magnetically for 2 to 3 hours at room temperature to obtain solution A; c. Place the solution A obtained in step b in a water bath at 45-60°C, slowly drop a 1 mol / L hydrochloric acid solution into the solution A at a uniform speed, and stir and mix at a uniform speed until the pH value of the mixed solution reaches 2-3, to obtain a solution B; d. Transfer solution B to a stainless steel hydrothermal kettle with a volume of 100 mL, heat at 180°C for 18 to 24 hours, cool naturally to 25°C, transfer to a centrifuge, centrifuge at 4000r / min for 10 to 20 minutes, wash repeatedly with deionized water and anhydrous ethanol for 6 times, remove the supernatant, and obtain precipitate C; put precipitate C into a vacuum drying oven, vacuum dry at 60°C for 6 to 8 hours to obtain nano tungsten trioxide (WO3); 2. Preparation of organic sensitive material polymer polyaniline e. Take 10 mL of aniline solution, repeatedly distill and purify to obtain a high-purity aniline solution, take 5 mL of the high-purity aniline solution and add it to 500 mL of 1 mol / L dilute hydrochloric acid solution, stir magnetically for 40 to 60 minutes, and obtain a mixed solution D; f. Weigh 11.4 g of ammonium persulfate (APS) and dissolve it in 50 mL of 1 mol / L hydrochloric acid solution to prepare an ammonium persulfate hydrochloric acid solution; slowly and uniformly add the ammonium persulfate hydrochloric acid solution to the mixed solution D at a rate of 5 drops / s using a long-necked funnel, and continue to stir and react in an ice-water bath for 2 to 3 hours to obtain a mixed solution E; g. Filter the mixed solution E by suction, and wash the filter cake obtained by suction filtration three times with 0.1 mol / L dilute hydrochloric acid solution, deionized water, and anhydrous ethanol in sequence to obtain a precipitate F; h. Dry the precipitate F under vacuum at 60° C. for 10 to 12 h to obtain polyaniline (PANI); 3. Preparation of WO3 / PANI composite materials i. The tungsten trioxide prepared in step d and the polyaniline prepared in step h were dissolved in 10 mL of deionized water in a mass ratio of 1 to 2, and ultrasonically treated for 10 to 20 min to obtain a WO3 / PANI suspension. The suspension was vacuum dried at 60°C for 10 to 12 h to obtain a WO3 / PANI composite material. The suspension was placed in a mortar and mechanically ground for more than 20 to 24 h, and then 0.5 to 1 mL of pine alcohol was added and ground to a slurry G; 4. Preparation of Flexible Electrochemical Sensors The flexible electrochemical sensor device structure based on rapid detection of trimethylamine in human urine includes a heating electrode and three electrodes; j. Take a piece of polyethylene naphthalate (PEN) insulating film and tear off the protective films on both sides. Take a dust-free cloth and dip it in an appropriate amount of anhydrous ethanol to wipe clean the flexible substrate (8) of the flexible electrochemical sensor of the present invention. Use a vacuum plasma cleaner to clean the surface of the flexible substrate (8). Place the cleaned flexible substrate (8) on the printing platform of a flexible microelectronic printer, install Ag conductive ink, use a dispensing needle with a diameter of 0.16 mm or 0.25 mm, use a dispensing process and set printing parameters to prepare a heating electrode pad (9) on the flexible substrate (8). After completion, place the substrate on an external heating table and dry it at 100° C. for 10 to 20 minutes to heat and cure. k. Use a flexible microelectronic printer, replace the Cu conductive ink and load it into the printer, use a dispensing process to reset the parameters in the middle of the solidified flexible substrate (8) to prepare a heating electrode (10), and after preparation, put it into a drying oven and vacuum bake it at 150° C. for 20 to 30 minutes to anneal and shape it; 1. Take a piece of PEN insulating film and tear off the protective films on both sides. Take a dust-free cloth and dip it in an appropriate amount of anhydrous ethanol to wipe it clean as the isolation layer (3) of the flexible electrochemical sensor of the present invention. Use a vacuum plasma cleaning machine to clean the surface of the isolation layer (3). Place the isolation layer (3) with the cleaned surface on the printing platform of a flexible microelectronic printer, replace it with Ag conductive ink, use a dispensing process and set printing parameters to print three electrode pads (4) and a reference electrode (5) on the isolation layer (3). After completion, place it on an external heating table and dry it at 100° C. for 15 to 20 minutes. m. Use a flexible microelectronic printer, replace it with C conductive ink, and use a dispensing process to prepare a working electrode (7) and an auxiliary electrode (6) on the isolation layer (3). After completion, put them into a drying oven and vacuum bake them at 120° C. for 20 to 30 minutes to anneal and fix them; n. The three electrode layers (1) and the heating electrode layer (2) of the sensor prepared in step k and step m are stacked from top to bottom in sequence, a proper amount of polyvinylidene fluoride (PVDF) is scraped on the front of the bottom heating electrode layer (2), and the back of the three electrode layers (1) is pressed on the center of the front of the heating electrode layer (2), and the three electrode layers (1) are placed in a drying oven, dried at 80° C. for 1 to 2 hours, and heated and cured; 5. Modification of working electrode o. The slurry G prepared in step i is dripped onto the working electrode (7) prepared in step m, and dried and solidified at room temperature to form a film to complete the modification of the working electrode, thereby completing the preparation of a flexible electrochemical sensor based on the rapid detection of trimethylamine in human urine.

2. The method for preparing a flexible electrochemical sensor for rapid detection of trimethylamine in human urine according to claim 1, characterized in that include: Solution A in step b is magnetically stirred at room temperature for 3 h; In step c, a 1 mol / L hydrochloric acid solution is added to solution A to adjust the pH value of solution B to 2.1; In step d, solution B was heated at 180° C. for 24 h in a stainless steel hydrothermal autoclave with a volume of 100 mL; centrifuged at a speed of 4000 r / min for 20 min, and the precipitate C was vacuum dried at 60° C. for 8 h.

3. The method for preparing a flexible electrochemical sensor for rapid detection of trimethylamine in human urine according to claim 1, characterized in that include: The mixed solution D in step e is magnetically stirred at room temperature for 60 min; The mixed solution E in step f was stirred in an ice-water bath for 3 h; In step h, the precipitate F was dried in vacuum at 60° C. for 12 h.

4. The method for preparing a flexible electrochemical sensor for rapid detection of trimethylamine in human urine according to claim 1, characterized in that include: The polyaniline and tungsten trioxide in step i are doped in a mass ratio of 1:1; Dissolve in 10 mL of deionized water and ultrasonically treat for 20 min to obtain a WO3 / PANI suspension; vacuum dry at 60 °C for 12 h to obtain a WO3 / PANI composite material, place in a mortar and grind mechanically for 24 h, then add 0.5 mL of pinene alcohol and grind to a slurry G.

5. The method for preparing a flexible electrochemical sensor for rapid detection of trimethylamine in human urine according to claim 1, characterized in that include: In step j, the flexible substrate (8) is a polyethylene naphthalate (PEN) insulating film, and its size is 16 mm*16 mm; In step 1, the isolation layer (3) is a PEN insulation film having a size of 16 mm*9 mm; The heating electrode pad (9) and the three-electrode pad (4) are Ag, the reference electrode (5) is Ag / Agcl, the heating electrode (10) is Cu, and the working electrode (7) and the auxiliary electrode (6) are C.

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