Electrochemical sensor for identifying amino acid enantiomers and its preparation method and application

Abstract

The present invention provides an electrochemical sensor for identifying amino acid enantiomers, and a preparation method and application thereof, which relate to the field of electrochemical technology. The sensor comprises a glassy carbon electrode and a xylose-inulin composite coating coated on the glassy carbon electrode. The preparation method comprises: S1: preparing a xylose-inulin composite material by self-assembly; S2: drop-coating the xylose-inulin composite material obtained in S1 on the surface of a glassy carbon electrode, and obtaining a xylose-inulin modified glassy carbon electrode after drying. The glassy carbon electrode modified with the composite material has a large number of active sites. By effectively utilizing the synergistic effect of xylose and inulin, the modified electrode exhibits selective recognition of amino acid enantiomers. The electrode of the present invention has good stability, specificity and chiral recognition ability for amino acid enantiomers, and has good application prospects in quantitative analysis of amino acid enantiomers.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical testing, and in particular to an electrochemical sensor for identifying amino acid enantiomers, and a preparation method and application thereof. Background Art

[0002] Chirality is a common property found in natural systems. Most important biomolecules possess chirality. Amino acids, for example, are important chiral compounds that serve as crucial biomarkers for assessing various metabolic diseases. Amino acids of different configurations share identical chemical and physical properties but exhibit significant differences in biological interactions, pharmacological activity, and metabolic behavior in biological systems, potentially even exhibiting severe toxic side effects. Therefore, establishing reliable, rapid, and efficient analytical and identification methods is crucial in fields such as medical pharmacology and biochemistry for the screening, diagnosis, and treatment of metabolic diseases.

[0003] Compared with conventional technologies for detecting amino acid enantiomers (such as high performance liquid chromatography, mass spectrometry, etc.), chiral electrochemical sensors have attracted widespread attention due to their low cost, high sensitivity, simple operation, fast response speed and easy miniaturization.

[0004] Current research indicates that the modification of glassy carbon electrodes with chiral carbon nanotubes, conductive polymers, chiral ionic liquids, carbon quantum dots, potato starch, β-cyclodextrin, and chitosan can effectively improve the modified electrode's ability to recognize amino acid enantiomers. However, many problems still exist when constructing electrochemical sensors using these materials. For example, Chinese patent CN118311112B discloses a homocysteine ​​molecularly imprinted electrochemical sensor, its preparation method, and application. This patent constructs a carboxylated multi-walled carbon nanotube-sodium dodecyl sulfate / glassy carbon electrode (MWCNTs-SDS / GCE) sensor for detecting homocysteine ​​content in serum, with a sensitivity of 3.3×10 -11mol / L LOD value, but the sensor film thickness is difficult to control, and it is easy to disperse in water and fall off. There are phenomena of template molecule leakage and uneven distribution of recognition sites, which will lead to unstable sensor output results. Chinese patent CN117309963A discloses a chiral recognition electrochemical sensor based on metal organic framework-chiral ionic liquid and its application in identifying Trp. The patent modifies the surface of a glassy carbon working electrode (GCE) with an appropriate amount of MWCNTs-MXene-CS composite material as an electrical signal amplification material and a metal organic framework-chiral ionic liquid composite material Fe-CIL as a chiral recognition material to construct a Fe-CIL / MWCNTs-MXene-CS / GCE chiral recognition electrochemical sensor. Although the sensor shows a faster response rate and has more detection targets such as tryptophan, phenylalanine, lysine and tyrosine, its chiral recognition ability for amino acids is still low. Under optimal conditions, the DPV oxidation peak potential difference of tryptophan enantiomers is only 28mV.

[0005] Based on this, in order to address the problems of electrochemical chiral sensors, such as strong water solubility or poor dispersibility of chiral selectors, which easily form uneven chiral interfaces, leading to low selectivity and poor repeatability, the present invention uses xylose and inulin as chiral selectors to construct a xylose-inulin composite material modified electrode as an electrochemical sensor to improve the stability and recognition ability of the electrode in detecting amino acid enantiomers. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides an electrochemical sensor for recognizing amino acid enantiomers, as well as a preparation method and application thereof. By modifying a glassy carbon electrode with xylose and inulin, the stability, specificity and chiral recognition ability of the modified electrode for amino acid enantiomers are effectively improved.

[0007] In order to achieve the above object, the present invention first provides an electrochemical sensor for identifying amino acid enantiomers, wherein the electrochemical sensor comprises a glassy carbon electrode and a xylose-inulin composite coating coated on the surface of the glassy carbon electrode.

[0008] Furthermore, in the xylose-inulin composite coating, the mass ratio of xylose to inulin is 0.2-5:1, such as but not limited to any one of 0.2:1, 0.3:1, 0.33:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc.

[0009] In a preferred embodiment, the mass ratio of xylose to inulin in the composite coating is 0.3-3:1.

[0010] Natural, edible xylose and inulin offer advantages such as good biocompatibility, non-toxicity, widespread availability, and low cost. Xylose (Xyl) is a monosaccharide, a five-carbon aldose, containing four hydroxyl groups in a six-membered ring molecule with multiple active sites. Inulin (Inu) is a polysaccharide derived from chicory, asparagus root, and garlic. It consists of fructose units linked by β(2→1) glycosidic bonds and typically has a glucose unit at the end. Inulin has a wide range of applications, including as a stabilizer and excipient. Extensive research has revealed that the combined use of xylose and inulin in a ratio of 1-5:1, preferably 1-3:1, can leverage their synergistic effects to impart optimal stability and chiral recognition of amino acid isomers to electrochemical sensors.

[0011] Furthermore, the present invention also provides a method for preparing the electrochemical sensor, comprising the following steps:

[0012] S1: Mix inulin and ultrapure water and dissolve them by ultrasonication to obtain a concentration of 0.5-10 mg mL -1 inulin solution; pipette 2-20mL of inulin solution and weigh 8-80.0mg of xylose into a reactor and mix them, and then a xylose-inulin composite material can be obtained after a hydrothermal reaction;

[0013] S2: drop-coating the xylose-inulin composite material obtained in S1 onto the surface of the glassy carbon electrode, and drying it to obtain the xylose-inulin modified glassy carbon electrode, i.e., the electrochemical sensor.

[0014] Furthermore, the concentration of inulin solution in S1 is 1-5 mg·mL -1 , optional such as 1 mg·mL -1 , 2 mg·mL -1 , 3 mg·mL -1 , 4 mg·mL -1 , 5 mg·mL -1 Any one of the above.

[0015] Furthermore, the mass ratio of xylose to inulin in the xylose-inulin composite material is 0.2-5:1, preferably 0.3-3:1, and optionally any one of 0.3:1, 0.33:1, 0.5:1, 1:1, 2:1, 3:1, etc.

[0016] Furthermore, the hydrothermal reaction temperature in step S1 is 80-140°C, exemplified but not limited to any one of 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, and 140°C. During the hydrothermal process, an effective cross-linking reaction is formed between xylose and inulin molecules. In the range of 80-140°C, the two may form a sheet-like structure with a suitable distribution of pores and active sites through intermolecular interactions such as hydrogen bonds and electrostatic interactions. These distributed pores and active sites can match the size and interaction sites of amino acid enantiomers, giving the modified electrode a chiral microenvironment, thereby enriching and recognizing amino acid enantiomers. When the hydrothermal temperature is too low, xylose and inulin are not fully cross-linked, resulting in a loose structure or weak specific recognition; when the hydrothermal temperature is too high, xylose, inulin and their surface functional groups will obviously decompose and dehydrate to produce highly carbonized substances. This process will destroy the chiral recognition sites of the original structure, resulting in a sharp decline in chiral recognition ability.

[0017] Furthermore, the hydrothermal reaction time in step S1 is 60-240 min, exemplified but not limited to any one of 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, 160 min, 170 min, 180 min, 190 min, 200 min, 210 min, 220 min, 230 min, and 240 min. If the hydrothermal time is too short, the reaction of xylose and inulin is insufficient, the composite material structure is not uniform, and the effective recognition site is insufficiently formed or not yet stable. If the hydrothermal time is too long, the composite material structure may coarsen, aggregate or be destroyed, the surface functional groups may overreact or decompose, and it is not conducive to the chiral recognition effect of the composite material modified electrode.

[0018] Furthermore, in S2, the drop coating amount of the xylose-inulin composite material is 2-15 μL, exemplified but not limited to any one of 2 μL, 3 μL, 4 μL, 5 μL, 6 μL, 7 μL, 8 μL, 9 μL, 10 μL, etc.; the present invention does not strictly limit the number of drop coatings, and the coating can be completed in one time, or it can be coated in multiple times, such as coating twice, three times, four times, etc., which can be selected according to actual needs. When the coating amount is too much, the thicker the modification layer, the more serious it will be. The electron transfer between the electrode surface and the amino acid isomers will be hindered, thereby reducing the current response and resulting in a decrease in recognition efficiency. When the coating amount is too little, the thinner the modification layer, the less enrichment of the amino acid isomers on the electrode surface will be reduced, which will reduce the current response and result in a decrease in recognition efficiency. The coating amount of the xylose-inulin composite material within the range can ensure sufficient amino acid recognition ability and current response effect.

[0019] Preferably, the drop-coating amount of the xylose-inulin composite material in S2 is 4-10 μL.

[0020] Furthermore, in S2, drying is performed by one or more methods including air, infrared lamp, and nitrogen flow, and the drying time is 30-240 minutes.

[0021] Furthermore, the present invention also provides an application of the electrochemical sensor in the selective identification of amino acid enantiomers, specifically: S1, building a three-electrode system: using the xylose-inulin modified glassy carbon electrode as the working electrode, the Ag / AgCl electrode as the reference electrode, and the platinum wire electrode as the counter electrode; S2, immersing the above three-electrode system in an electrolyte solution containing amino acid enantiomers for electrochemical scanning to identify and detect the amino acid enantiomers.

[0022] Preferably, the electrolyte solution is selected from one or more of an inorganic salt buffer solution and an inorganic acid buffer solution; in one embodiment, the electrolyte solution is a phosphate buffer solution (PBS); in one embodiment, the electrolyte solution is a HAc-NaAc buffer solution; in one embodiment, the electrolyte solution is a BR solution.

[0023] Preferably, the concentration of the electrolyte solution is 0.01-1 mol / L, more preferably 0.01-0.5 mol / L, and even more preferably 0.05-0.2 mol / L.

[0024] Preferably, the electrochemical scan may adopt any one of cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV); in one embodiment, the electrochemical scan adopts square wave voltammetry.

[0025] Preferably, the potential window of the electrochemical scan is 0-1.4V.

[0026] Preferably, the amino acid comprises at least one of tyrosine, tryptophan, histidine or phenylalanine.

[0027] In a preferred embodiment, the amino acid is tyrosine.

[0028] The above solution of the present invention has the following beneficial effects:

[0029] (1) The electrochemical sensor of the present invention, namely the xylose-inulin modified glassy carbon electrode, exhibits excellent selectivity based on the synergistic effect between xylose and inulin. By utilizing the wrinkled sheet structure of the xylose-inulin composite material to expose abundant active sites, it can efficiently capture and identify amino acid enantiomers, showing high electrochemical signal and chiral recognition specificity. At the same time, the composite material is uniform and can be coated on the surface of the glassy carbon electrode to form a film. Based on the synergistic effect of the composite material, the prepared glassy carbon electrode can obtain a stable catalytic current response when electrochemically detecting amino acid L / D enantiomers, showing good application prospects for the quantitative analysis of amino acid enantiomers.

[0030] (2) The present invention utilizes inulin to effectively improve the instability of the electrode sensing interface; hydrothermal self-assembly of xylose and inulin with a specific content can not only further expand the specific surface area of ​​the composite material by utilizing the wrinkled sheet structure and enhance the enrichment of amino acid enantiomers on the electrode surface, but also effectively retain the xylose-inulin molecular recognition ability, thereby ensuring good conductivity and recognition molecular characteristics.

[0031] (3) The method for detecting / identifying amino acid enantiomers using the xylose-inulin modified glassy carbon electrode prepared by the present invention is convenient, efficient, and time-saving, and can be used for simple and rapid qualitative and quantitative analysis of amino acid enantiomers.

[0032] (4) The xylose-inulin composite material used in the present invention has the advantages of being green and environmentally friendly, having good biocompatibility, good stability, and low production cost, which is conducive to expanding its scope of use in actual electrochemical detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 : Scanning electron micrograph of xylose.

[0034] Figure 2 : Scanning electron micrograph of inulin.

[0035] Figure 3 : Scanning electron microscopy images of xylose-inulin composite materials.

[0036] Figure 4 : Comparison of infrared spectra of xylose (Xyl), inulin (Inu) and xylose-inulin composite material (Xyl-Inu).

[0037] Figure 5 : Square wave voltammetry curves of bare GCE recognizing tyrosine enantiomers.

[0038] Figure 6 : Square wave voltammetry curves of xylose modified electrode (Xyl / GCE) recognizing tyrosine enantiomers.

[0039] Figure 7: Square wave voltammetry curves of inulin modified electrode (Inu / GCE) for recognition of tyrosine enantiomers.

[0040] Figure 8 : Square wave voltammetry curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) for the recognition of tyrosine enantiomers.

[0041] Figure 9 : Square wave voltammetry curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) for the detection of L-tyrosine at different concentrations.

[0042] Figure 10 : Square wave voltammetry curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) for the detection of D-tyrosine at different concentrations.

[0043] Figure 11 : Linearity curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) for the detection of L-tyrosine and D-tyrosine at different concentrations.

[0044] Figure 12 : Square wave voltammetry curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) recognizing tryptophan enantiomers (Trp).

[0045] Figure 13 : Square wave voltammetry curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) recognizing phenylalanine enantiomers (Phe).

[0046] Figure 14 : Square wave voltammetry curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) recognizing histidine enantiomers (His).

[0047] Figure 15 : Square wave voltammetry curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) recognizing tyrosine enantiomers (Tyr).

[0048] Figure 16 : Comparison of the recognition efficiency of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) for tryptophan (Trp), phenylalanine (Phe), histidine (His) and tyrosine (Tyr) enantiomers.

[0049] Attachment Figure 5-8 In the figure, curve a corresponds to L-tyrosine (L-Tyr), and curve b corresponds to D-tyrosine (D-Tyr). From the current separation of the two curves a and b (in terms of I L / I D The difference in recognition ability can be seen from the potential difference (ΔEp). DETAILED DESCRIPTION

[0050] To make the technical problems, technical solutions, and advantages to be solved by the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0051] It should be understood that the methods described herein are exemplary in nature, and that these specific embodiments or examples should not be considered restrictive, as many variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various actions shown may be performed in the order shown, in other orders, or omitted in some cases. References to "embodiments" throughout the specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner, as will be apparent to one of ordinary skill in the art.

[0052] In the following terms, "μM" refers to "μmol / L", "mM" refers to "mmol / L", and "M" refers to "mol / L".

[0053] Example 1

[0054] This embodiment provides an electrochemical sensor for recognizing amino acid enantiomers, and the preparation method is as follows:

[0055] S1: Weigh 80 mg of inulin, add 20.0 mL of ultrapure water, and sonicate for 3 min to dissolve it to a concentration of 4 mg mL -1 inulin solution; weigh 20.0 mg of xylose into the inner lining of the reactor, then add 10.0 mL of the above inulin solution, and hydrothermally treat at 130 ° C for 120 min. After the reaction is completed, naturally cool to room temperature and pour out the reaction liquid to obtain a xylose-inulin composite material.

[0056] S2: 6 μL of the xylose-inulin composite material was transferred using a pipette and dropped onto the surface of a clean glassy carbon electrode, which was then dried in an infrared drying oven for 30 min to obtain the electrochemical sensor, i.e., the xylose-inulin modified glassy carbon electrode.

[0057] Example 2

[0058] This embodiment provides an electrochemical sensor for recognizing amino acid enantiomers, and the preparation method is as follows:

[0059] S1: Weigh 100 mg of inulin, add 20.0 mL of ultrapure water, and sonicate for 5 min to dissolve it to obtain a concentration of 5 mg mL -1 inulin solution; weigh 40.0 mg of xylose into the inner lining of the reactor, then add 8.0 mL of the above inulin solution, and hydrothermally treat at 100 ° C for 180 min. After the reaction is completed, naturally cool to room temperature and pour out the reaction liquid to obtain a xylose-inulin composite material.

[0060] S2: Use a pipette to transfer 10 μL of the xylose-inulin composite material, apply it dropwise on the surface of the glassy carbon electrode, and air dry it for 240 minutes to obtain the xylose-inulin modified glassy carbon electrode.

[0061] Example 3

[0062] This embodiment provides an electrochemical sensor for recognizing amino acid enantiomers, and the preparation method is as follows:

[0063] S1: Weigh 16 mg of inulin, add 4.0 mL of ultrapure water, and sonicate for 2 min to dissolve it to obtain a concentration of 4 mg mL -1 inulin solution; weigh 16.0 mg of xylose into the inner lining of the reactor, then add 4.0 mL of the above inulin solution, and hydrothermally treat at 120° C. for 120 min. After the reaction is completed, naturally cool to room temperature and pour out the reaction liquid to obtain a xylose-inulin composite material.

[0064] S2: Use a pipette to transfer 8 μL of the xylose-inulin composite material, apply it dropwise on the surface of the glassy carbon electrode, and dry it in a nitrogen flow for 60 minutes to obtain the xylose-inulin modified glassy carbon electrode.

[0065] Example 4

[0066] This embodiment provides an electrochemical sensor for recognizing amino acid enantiomers, and the preparation method is as follows:

[0067] S1: Weigh 32 mg of inulin, add 16.0 mL of ultrapure water, and sonicate for 3 min to dissolve it to obtain a concentration of 2 mg mL -1 inulin solution; weigh 96.0 mg of xylose into the lining of the reactor, then add 16.0 mL of the above inulin solution, and hydrothermally treat at 100 ° C for 240 min. After the reaction is completed, naturally cool to room temperature and pour out the reaction liquid to obtain a xylose-inulin composite material.

[0068] S2: Use a pipette to transfer 9 μL of the xylose-inulin composite material, apply it dropwise on the surface of the glassy carbon electrode, and dry it in an infrared drying oven for 120 minutes to obtain the xylose-inulin modified glassy carbon electrode.

[0069] Attachment Figure 1-3The scanning electron microscope images of xylose, inulin and xylose-inulin composite material (Example 1) are shown in Figure 2. Figure 1 It can be seen that xylose presents a continuous and uniform sheet-like film structure. Figure 2 It can be seen that inulin has a folded, rough and cracked flake structure. Figure 3 The xylose-inulin composite exhibits a folded, wrinkled sheet structure with a large surface area, exposing more active sites and facilitating chiral recognition of amino acid enantiomers. The structure of the xylose-inulin composite differs slightly from that of xylose and inulin alone, indicating successful assembly.

[0070] Attachment Figure 4 1 and 2 are infrared spectra comparison curves of xylose (Xyl), inulin (Inu) and the xylose-inulin composite material (Xyl-Inu) of Example 1. Figure 4 Observe the infrared spectrum of xylose at 3210 cm -1 、2889cm -1 、1119cm -1 and 1031cm -1 The characteristic absorption peaks at 3221cm are attributed to the stretching vibration of OH, CH, CO and the asymmetric stretching vibration of epoxy COC. -1 The broad peak at 2889 cm-1 belongs to the stretching vibration of OH. -1 The absorption peak at 1129 cm corresponds to the stretching vibration of CH. -1 The asymmetric stretching vibration of COC is at 1036 cm -1 The characteristic peak at can be attributed to the stretching vibration of CO. The infrared spectrum of the xylose-inulin composite material is almost consistent with the spectrum of xylose and inulin, but its characteristic peak is slightly red-shifted, which may be attributed to the intermolecular interaction between xylose and inulin, indicating that xylose and inulin have been successfully assembled.

[0071] Example 5

[0072] This embodiment provides the application of the electrochemical sensor in selectively identifying amino acid enantiomers, specifically:

[0073] S1. Build a three-electrode system: Use the xylose-inulin-modified glassy carbon electrode prepared in Example 1 as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire electrode as the counter electrode. S2. Immerse the three-electrode system in a phosphate buffer solution (0.1 M, pH 7.0) containing amino acid enantiomers to perform electrochemical scanning to identify and detect the amino acid enantiomers. The electrochemical scanning potential windows for tyrosine (Tyr) enantiomers, tryptophan (Trp) enantiomers, phenylalanine (Phe) enantiomers, and histidine (His) enantiomers are 0-1.4 V, and the SWV frequency is 15 Hz.

[0074] The material characterization diagram and test results of the electrochemical sensor are analyzed as follows:

[0075] This application uses square wave voltammetry (SWV) to analyze tyrosine (Tyr) enantiomers. Figure 5 The SWV curve of bare electrode (bare GCE) for the recognition of Tyr enantiomers is shown in the figure. As can be seen from the figure, the SWV peak potential and peak current almost overlap, which indicates that bare GCE does not have the ability to chirally recognize Tyr enantiomers due to the lack of chiral selectors. Figure 8 It can be seen that the peak current response ratio (I L / I D =2.22) and the peak potential difference was large (ΔEp=36mV). Its recognition efficiency was much higher than that of xylose-modified glassy carbon electrode (Xyl / GCE, I L / I D =1.23, ΔEp=12mV, attached Figure 6 ) and inulin-modified glassy carbon electrode (Inu / GCE, I L / I D =1.22, ΔEp=16mV, attached Figure 7 These results indicate that the xylose-inulin composite material assembled by the synergistic action of xylose and inulin has a folded, wrinkled sheet structure that exposes abundant active sites, which can efficiently capture and recognize Tyr enantiomers, showing high electrochemical signals and chiral recognition specificity.

[0076] Attachment Figure 9-10 This is a square wave voltammetry curve of the xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) in Example 1 of this application for detecting L-tyrosine and D-tyrosine at different concentrations. Figure 11The linear curves of xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) for detecting L-tyrosine and D-tyrosine at different concentrations are shown in the figure. As shown in the figure, within the concentration range of 0.01-1.0 mM, the peak current of Xyl-Inu / GCE increases with the increase of Tyr enantiomer concentration, and a good linear relationship is shown ( R 2 L-Tyr = 0.99529 and R 2 D-Tyr = 0.99799). The detection limits of D-Tyr and L-Tyr were calculated based on the three-fold signal-to-noise ratio ( LOD ) were 0.97 μM and 2.32 μM, respectively.

[0077] Attachment Figure 9-12 The following are the square wave voltammetry curves of the xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) in Example 1 of the present application for detecting the same concentration (1 mM) of Trp, Phe, His and Tyr. Figure 16 This figure compares the recognition efficiency of the xylose-inulin modified glassy carbon electrode (Xyl-Inu / GCE) for tryptophan (Trp), phenylalanine (Phe), histidine (His), and tyrosine (Tyr) enantiomers. It can be seen that Xyl-Inu / GCE exhibits excellent stereospecificity for the Tyr enantiomer. This is primarily due to differences in hydrogen bonding stereospecificity caused by structural differences among the four amino acids. Specifically, the amino / carboxyl / phenolic hydroxyl groups of the Tyr enantiomer can form hydrogen bonds with the hydroxyl groups of Xyl-Inu, while Trp, Phe, and His lack phenolic hydroxyl groups, resulting in weakened intermolecular interactions and even reducing the chiral recognition efficiency to below 1.00.

[0078] The method for detecting / identifying amino acid enantiomers using the xylose-inulin modified electrode prepared by the present invention is convenient, efficient, and low-cost, and can simply and quickly identify and quantitatively analyze amino acid enantiomers.

[0079] While preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0080] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

Claims

1. Application of an electrochemical sensor in selectively identifying amino acid enantiomers, characterized in that: Specifically, S1. Build a three-electrode system: use a xylose-inulin-modified glassy carbon electrode as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire electrode as the counter electrode; S2. Immerse the three-electrode system in an electrolyte solution containing amino acid enantiomers to perform electrochemical scanning to identify and detect the amino acid enantiomers; the electrochemical sensor includes a glassy carbon electrode and a xylose-inulin composite coating coated on its surface; In the xylose-inulin composite coating, the mass ratio of xylose to inulin is 0.2-5:1; The preparation method of the electrochemical sensor comprises the following steps: S1: Mix inulin and ultrapure water and dissolve them by ultrasonication to obtain a concentration of 0.5-10 mg mL -1 inulin solution; pipette 2-20mL of inulin solution and weigh 8-80.0mg of xylose into a reactor and mix them, and then a xylose-inulin composite material can be obtained after a hydrothermal reaction; S2: drop-coating the xylose-inulin composite material obtained in S1 onto the surface of a glassy carbon electrode, and drying the xylose-inulin modified glassy carbon electrode, i.e., the electrochemical sensor; The amino acid includes at least one of tyrosine, tryptophan, histidine or phenylalanine.

2. The use according to claim 1, characterized in that The concentration of inulin solution in S1 is 1-5 mg·mL -1 ; and / or, the drop-coating amount of the xylose-inulin composite material is 2-15 μL.

3. The use according to claim 1, characterized in that In step S1, the hydrothermal reaction temperature is 80-140° C., and the hydrothermal reaction time is 60-240 min.

4. The use according to claim 1, characterized in that The drop coating amount of the xylose-inulin composite material is 4-10 μL.

5. The use according to claim 1, characterized in that The electrolyte solution is selected from one or more of an inorganic salt buffer solution and an inorganic acid buffer solution; and / or the concentration of the electrolyte solution is 0.01-1 mol / L; and / or the electrochemical scan adopts any one of cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry; and / or the potential window of the electrochemical scan is 0-1.4V.

6. The use according to claim 1, characterized in that The electrolyte solution is a phosphate buffer solution; and / or the concentration of the electrolyte solution is 0.05-0.2 mol / L.

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